Adding Claude related files

Spatial Polyakov Loop implementation

Grid/Makefile.am

@@ -54,22 +54,24 @@ Version.h: version-cache
 include Make.inc
 include Eigen.inc
 
-extra_sources+=$(WILS_FERMION_FILES)
-extra_sources+=$(STAG_FERMION_FILES)
+if BUILD_FERMION_INSTANTIATIONS
+  extra_sources+=$(WILS_FERMION_FILES)
+  extra_sources+=$(STAG_FERMION_FILES)
 if BUILD_ZMOBIUS
-  extra_sources+=$(ZWILS_FERMION_FILES)
+    extra_sources+=$(ZWILS_FERMION_FILES)
 endif
 if BUILD_GPARITY
-  extra_sources+=$(GP_FERMION_FILES)
+    extra_sources+=$(GP_FERMION_FILES)
 endif
 if BUILD_FERMION_REPS
-  extra_sources+=$(ADJ_FERMION_FILES)
-  extra_sources+=$(TWOIND_FERMION_FILES)
+    extra_sources+=$(ADJ_FERMION_FILES)
+    extra_sources+=$(TWOIND_FERMION_FILES)
 endif
 if BUILD_SP
     extra_sources+=$(SP_FERMION_FILES)
 if BUILD_FERMION_REPS
-    extra_sources+=$(SP_TWOIND_FERMION_FILES)
+      extra_sources+=$(SP_TWOIND_FERMION_FILES)
+endif
 endif
 endif
 

Grid/algorithms/blas/BatchedBlas.h

@@ -28,6 +28,7 @@ Author: Peter Boyle <pboyle@bnl.gov>
 #pragma once
 
 #ifdef GRID_HIP
+#include <hip/hip_version.h>
 #include <hipblas/hipblas.h>
 #endif
 #ifdef GRID_CUDA
@@ -255,16 +256,29 @@ public:
     if ( OpB == GridBLAS_OP_N ) hOpB = HIPBLAS_OP_N;
     if ( OpB == GridBLAS_OP_T ) hOpB = HIPBLAS_OP_T;
     if ( OpB == GridBLAS_OP_C ) hOpB = HIPBLAS_OP_C;
+#if defined(HIP_VERSION_MAJOR) && (HIP_VERSION_MAJOR >=7)
     auto err = hipblasZgemmBatched(gridblasHandle,
 				   hOpA,
 				   hOpB,
 				   m,n,k,
-				   (hipblasDoubleComplex *) &alpha_p[0],
-				   (hipblasDoubleComplex **)&Amk[0], lda,
-				   (hipblasDoubleComplex **)&Bkn[0], ldb,
-				   (hipblasDoubleComplex *) &beta_p[0],
-				   (hipblasDoubleComplex **)&Cmn[0], ldc,
+				   (hipDoubleComplex *) &alpha_p[0],
+				   (hipDoubleComplex **)&Amk[0], lda,
+				   (hipDoubleComplex **)&Bkn[0], ldb,
+				   (hipDoubleComplex *) &beta_p[0],
+				   (hipDoubleComplex **)&Cmn[0], ldc,
 				   batchCount);
+#else
+    auto err = hipblasZgemmBatched(gridblasHandle,
+                                   hOpA,
+                                   hOpB,
+                                   m,n,k,
+                                   (hipblasDoubleComplex *) &alpha_p[0],
+                                   (hipblasDoubleComplex **)&Amk[0], lda,
+                                   (hipblasDoubleComplex **)&Bkn[0], ldb,
+                                   (hipblasDoubleComplex *) &beta_p[0],
+                                   (hipblasDoubleComplex **)&Cmn[0], ldc,
+                                   batchCount);
+#endif
     //	 std::cout << " hipblas return code " <<(int)err<<std::endl;
     GRID_ASSERT(err==HIPBLAS_STATUS_SUCCESS);
 #endif
@@ -503,17 +517,30 @@ public:
     if ( OpB == GridBLAS_OP_N ) hOpB = HIPBLAS_OP_N;
     if ( OpB == GridBLAS_OP_T ) hOpB = HIPBLAS_OP_T;
     if ( OpB == GridBLAS_OP_C ) hOpB = HIPBLAS_OP_C;
+#if defined(HIP_VERSION_MAJOR) && (HIP_VERSION_MAJOR >=7)
     auto err = hipblasCgemmBatched(gridblasHandle,
 				   hOpA,
 				   hOpB,
 				   m,n,k,
-				   (hipblasComplex *) &alpha_p[0],
-				   (hipblasComplex **)&Amk[0], lda,
-				   (hipblasComplex **)&Bkn[0], ldb,
-				   (hipblasComplex *) &beta_p[0],
-				   (hipblasComplex **)&Cmn[0], ldc,
+				   (hipComplex *) &alpha_p[0],
+				   (hipComplex **)&Amk[0], lda,
+				   (hipComplex **)&Bkn[0], ldb,
+				   (hipComplex *) &beta_p[0],
+				   (hipComplex **)&Cmn[0], ldc,
 				   batchCount);
+#else
+    auto err = hipblasCgemmBatched(gridblasHandle,
+                                   hOpA,
+                                   hOpB,
+                                   m,n,k,
+                                   (hipblasComplex *) &alpha_p[0],
+                                   (hipblasComplex **)&Amk[0], lda,
+                                   (hipblasComplex **)&Bkn[0], ldb,
+                                   (hipblasComplex *) &beta_p[0],
+                                   (hipblasComplex **)&Cmn[0], ldc,
+                                   batchCount);
 
+#endif
     GRID_ASSERT(err==HIPBLAS_STATUS_SUCCESS);
 #endif
 #ifdef GRID_CUDA
@@ -1094,11 +1121,19 @@ public:
     GRID_ASSERT(info.size()==batchCount);
 
 #ifdef GRID_HIP
+#if defined(HIP_VERSION_MAJOR) && (HIP_VERSION_MAJOR >=7)
     auto err = hipblasZgetrfBatched(gridblasHandle,(int)n,
-				    (hipblasDoubleComplex **)&Ann[0], (int)n,
+				    (hipDoubleComplex **)&Ann[0], (int)n,
 				    (int*) &ipiv[0],
 				    (int*) &info[0],
 				    (int)batchCount);
+#else
+    auto err = hipblasZgetrfBatched(gridblasHandle,(int)n,
+                                    (hipblasDoubleComplex **)&Ann[0], (int)n,
+                                    (int*) &ipiv[0],
+                                    (int*) &info[0],
+                                    (int)batchCount);
+#endif
     GRID_ASSERT(err==HIPBLAS_STATUS_SUCCESS);
 #endif
 #ifdef GRID_CUDA
@@ -1124,11 +1159,20 @@ public:
     GRID_ASSERT(info.size()==batchCount);
 
 #ifdef GRID_HIP
+#if defined(HIP_VERSION_MAJOR) && (HIP_VERSION_MAJOR >=7)
     auto err = hipblasCgetrfBatched(gridblasHandle,(int)n,
-				    (hipblasComplex **)&Ann[0], (int)n,
+				    (hipComplex **)&Ann[0], (int)n,
 				    (int*) &ipiv[0],
 				    (int*) &info[0],
 				    (int)batchCount);
+#else
+    auto err = hipblasCgetrfBatched(gridblasHandle,(int)n,
+                                    (hipblasComplex **)&Ann[0], (int)n,
+                                    (int*) &ipiv[0],
+                                    (int*) &info[0],
+                                    (int)batchCount);
+#endif
+
     GRID_ASSERT(err==HIPBLAS_STATUS_SUCCESS);
 #endif
 #ifdef GRID_CUDA
@@ -1201,12 +1245,22 @@ public:
     GRID_ASSERT(Cnn.size()==batchCount);
 
 #ifdef GRID_HIP
+#if defined(HIP_VERSION_MAJOR) && (HIP_VERSION_MAJOR >=7)
     auto err = hipblasZgetriBatched(gridblasHandle,(int)n,
-				    (hipblasDoubleComplex **)&Ann[0], (int)n,
+				    (hipDoubleComplex **)&Ann[0], (int)n,
 				    (int*) &ipiv[0],
-				    (hipblasDoubleComplex **)&Cnn[0], (int)n,
+				    (hipDoubleComplex **)&Cnn[0], (int)n,
 				    (int*) &info[0],
 				    (int)batchCount);
+#else
+    auto err = hipblasZgetriBatched(gridblasHandle,(int)n,
+                                    (hipblasDoubleComplex **)&Ann[0], (int)n,
+                                    (int*) &ipiv[0],
+                                    (hipblasDoubleComplex **)&Cnn[0], (int)n,
+                                    (int*) &info[0],
+                                    (int)batchCount);
+
+#endif
     GRID_ASSERT(err==HIPBLAS_STATUS_SUCCESS);
 #endif
 #ifdef GRID_CUDA
@@ -1235,12 +1289,21 @@ public:
     GRID_ASSERT(Cnn.size()==batchCount);
 
 #ifdef GRID_HIP
+#if defined(HIP_VERSION_MAJOR) && (HIP_VERSION_MAJOR >=7)
     auto err = hipblasCgetriBatched(gridblasHandle,(int)n,
-				    (hipblasComplex **)&Ann[0], (int)n,
+				    (hipComplex **)&Ann[0], (int)n,
 				    (int*) &ipiv[0],
-				    (hipblasComplex **)&Cnn[0], (int)n,
+				    (hipComplex **)&Cnn[0], (int)n,
 				    (int*) &info[0],
 				    (int)batchCount);
+#else
+    auto err = hipblasCgetriBatched(gridblasHandle,(int)n,
+                                    (hipblasComplex **)&Ann[0], (int)n,
+                                    (int*) &ipiv[0],
+                                    (hipblasComplex **)&Cnn[0], (int)n,
+                                    (int*) &info[0],
+                                    (int)batchCount);
+#endif
     GRID_ASSERT(err==HIPBLAS_STATUS_SUCCESS);
 #endif
 #ifdef GRID_CUDA

Grid/algorithms/iterative/AdefMrhs.h

@@ -92,8 +92,8 @@ class TwoLevelCGmrhs
   // Vector case
   virtual void operator() (std::vector<Field> &src, std::vector<Field> &x)
   {
-    //    SolveSingleSystem(src,x);
-    SolvePrecBlockCG(src,x);
+    SolveSingleSystem(src,x);
+	// SolvePrecBlockCG(src,x);
   }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////

Grid/algorithms/multigrid/Aggregates.h

@@ -97,7 +97,7 @@ public:
 
     RealD scale;
 
-    ConjugateGradient<FineField> CG(1.0e-3,400,false);
+    ConjugateGradient<FineField> CG(1.0e-4,2000,false);
     FineField noise(FineGrid);
     FineField Mn(FineGrid);
 
@@ -131,7 +131,10 @@ public:
     RealD scale;
 
     TrivialPrecon<FineField> simple_fine;
-    PrecGeneralisedConjugateResidualNonHermitian<FineField> GCR(0.001,30,DiracOp,simple_fine,12,12);
+    //    PrecGeneralisedConjugateResidualNonHermitian<FineField> GCR(0.001,10,DiracOp,simple_fine,30,30);
+    //    PrecGeneralisedConjugateResidualNonHermitian<FineField> GCR(0.001,10,DiracOp,simple_fine,12,12);
+    //    PrecGeneralisedConjugateResidualNonHermitian<FineField> GCR(0.001,30,DiracOp,simple_fine,12,12);
+    PrecGeneralisedConjugateResidualNonHermitian<FineField> GCR(0.001,30,DiracOp,simple_fine,10,10);
     FineField noise(FineGrid);
     FineField src(FineGrid);
     FineField guess(FineGrid);
@@ -146,16 +149,16 @@ public:
       
       DiracOp.Op(noise,Mn); std::cout<<GridLogMessage << "noise   ["<<b<<"] <n|Op|n> "<<innerProduct(noise,Mn)<<std::endl;
 
-      for(int i=0;i<2;i++){
+      for(int i=0;i<3;i++){
 	//  void operator() (const Field &src, Field &psi){
 #if 1
-	std::cout << GridLogMessage << " inverting on noise "<<std::endl;
+	if (i==0)std::cout << GridLogMessage << " inverting on noise "<<std::endl;
 	src = noise;
 	guess=Zero();
 	GCR(src,guess);
 	subspace[b] = guess;
 #else
-	std::cout << GridLogMessage << " inverting on zero "<<std::endl;
+	if (i==0)std::cout << GridLogMessage << " inverting on zero "<<std::endl;
 	src=Zero();
 	guess = noise;
 	GCR(src,guess);
@@ -167,7 +170,7 @@ public:
 
       }
 
-      DiracOp.Op(noise,Mn); std::cout<<GridLogMessage << "filtered["<<b<<"] <f|Op|f> "<<innerProduct(noise,Mn)<<std::endl;
+      DiracOp.Op(noise,Mn); std::cout<<GridLogMessage << "filtered["<<b<<"] <f|Op|f> "<<innerProduct(noise,Mn)<<" <f|OpDagOp|f>"<<norm2(Mn)<<std::endl;
       subspace[b]   = noise;
 
     }

Grid/qcd/QCD.h

@@ -596,16 +596,32 @@ template<int Index,class vobj> inline vobj transposeColour(const vobj &lhs){
 //////////////////////////////////////////
 // Trace lattice and non-lattice
 //////////////////////////////////////////
+#define GRID_UNOP(name)   name
+#define GRID_DEF_UNOP(op, name)						\
+  template <typename T1, typename std::enable_if<is_lattice<T1>::value||is_lattice_expr<T1>::value,T1>::type * = nullptr> \
+  inline auto op(const T1 &arg) ->decltype(LatticeUnaryExpression<GRID_UNOP(name),T1>(GRID_UNOP(name)(), arg)) \
+  {									\
+    return     LatticeUnaryExpression<GRID_UNOP(name),T1>(GRID_UNOP(name)(), arg); \
+  }
+
 template<int Index,class vobj>
 inline auto traceSpin(const Lattice<vobj> &lhs) -> Lattice<decltype(traceIndex<SpinIndex>(vobj()))>
 {
   return traceIndex<SpinIndex>(lhs);
 }
+
+GridUnopClass(UnaryTraceSpin, traceIndex<SpinIndex>(a));
+GRID_DEF_UNOP(traceSpin, UnaryTraceSpin);
+
 template<int Index,class vobj>
 inline auto traceColour(const Lattice<vobj> &lhs) -> Lattice<decltype(traceIndex<ColourIndex>(vobj()))>
 {
   return traceIndex<ColourIndex>(lhs);
 }
+
+GridUnopClass(UnaryTraceColour, traceIndex<ColourIndex>(a));
+GRID_DEF_UNOP(traceColour, UnaryTraceColour);
+
 template<int Index,class vobj>
 inline auto traceSpin(const vobj &lhs) -> Lattice<decltype(traceIndex<SpinIndex>(lhs))>
 {
@@ -617,6 +633,8 @@ inline auto traceColour(const vobj &lhs) -> Lattice<decltype(traceIndex<ColourIn
   return traceIndex<ColourIndex>(lhs);
 }
 
+#undef GRID_UNOP
+#undef GRID_DEF_UNOP
 //////////////////////////////////////////
 // Current types
 //////////////////////////////////////////

Grid/qcd/modules/ObservableModules.h

@@ -103,6 +103,18 @@ class PolyakovMod: public ObservableModule<PolyakovLogger<Impl>, NoParameters>{
   PolyakovMod(): ObsBase(NoParameters()){}
 };
 
+template < class Impl >
+class SpatialPolyakovMod: public ObservableModule<SpatialPolyakovLogger<Impl>, NoParameters>{
+  typedef ObservableModule<SpatialPolyakovLogger<Impl>, NoParameters> ObsBase;
+  using ObsBase::ObsBase; // for constructors
+
+  // acquire resource
+  virtual void initialize(){
+    this->ObservablePtr.reset(new SpatialPolyakovLogger<Impl>());
+  }
+  public:
+  SpatialPolyakovMod(): ObsBase(NoParameters()){}
+};
 
 template < class Impl >
 class TopologicalChargeMod: public ObservableModule<TopologicalCharge<Impl>, TopologyObsParameters>{

Grid/qcd/observables/polyakov_loop.h

@@ -2,11 +2,12 @@
 
 Grid physics library, www.github.com/paboyle/Grid
 
-Source file: ./lib/qcd/modules/polyakov_line.h
+Source file: ./Grid/qcd/observables/polyakov_loop.h
 
-Copyright (C) 2017
+Copyright (C) 2025
 
 Author: David Preti <david.preti@csic.es>
+Author: Alexis Verney-Provatas <2414441@swansea.ac.uk>
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -60,4 +61,43 @@ class PolyakovLogger : public HmcObservable<typename Impl::Field> {
   }
 };
 
+template <class Impl>
+class SpatialPolyakovLogger : public HmcObservable<typename Impl::Field> {
+ public:
+    // here forces the Impl to be of gauge fields
+    // if not the compiler will complain
+    INHERIT_GIMPL_TYPES(Impl);
+
+     // necessary for HmcObservable compatibility
+    typedef typename Impl::Field Field;
+
+    void TrajectoryComplete(int traj,
+                            Field &U,
+                            GridSerialRNG &sRNG,
+                            GridParallelRNG &pRNG) {
+
+    // Save current numerical output precision
+    int def_prec = std::cout.precision();
+
+    // Assume that the dimensions are D=3+1
+    int Ndim = 3;
+    ComplexD polyakov;
+   
+    // Iterate over the spatial directions and print the average spatial polyakov loop
+    // over them 
+    for (int idx=0; idx<Ndim; idx++) {
+        polyakov = WilsonLoops<Impl>::avgPolyakovLoop(U, idx);
+    
+        std::cout << GridLogMessage
+            << std::setprecision(std::numeric_limits<Real>::digits10 + 1)
+            << "Polyakov Loop in the " << idx << " spatial direction : [ " << traj << " ] "<< polyakov << std::endl;
+
+    }
+
+    // Return to original output precision
+    std::cout.precision(def_prec);
+
+  }
+};
+
 NAMESPACE_END(Grid);

Grid/qcd/utils/Sp2n.impl.h

@@ -254,9 +254,9 @@ static void testGenerators(GroupName::Sp) {
   }
 }
 
-template <int N>
-static Lattice<iScalar<iScalar<iMatrix<vComplexD, N> > > >
-ProjectOnGeneralGroup(const Lattice<iScalar<iScalar<iMatrix<vComplexD, N> > > > &Umu, GroupName::Sp) {
+template <class vtype, int N>
+static Lattice<iScalar<iScalar<iMatrix<vtype, N> > > >
+ProjectOnGeneralGroup(const Lattice<iScalar<iScalar<iMatrix<vtype, N> > > > &Umu, GroupName::Sp) {
   return ProjectOnSpGroup(Umu);
 }
 

Grid/qcd/utils/WilsonLoops.h

@@ -177,25 +177,43 @@ public:
   }
 
   //////////////////////////////////////////////////
-  // average over all x,y,z the temporal loop
+  // average Polyakov loop in mu direction over all directions != mu
   //////////////////////////////////////////////////
-  static ComplexD avgPolyakovLoop(const GaugeField &Umu) {  //assume Nd=4
-    GaugeMat Ut(Umu.Grid()), P(Umu.Grid());
+  static ComplexD avgPolyakovLoop(const GaugeField &Umu, const int mu) {  //assume Nd=4
+    
+    // Protect against bad value of mu [0, 3]
+    if ((mu < 0 ) || (mu > 3)) {
+      std::cout << GridLogError << "Index is not an integer inclusively between 0 and 3." << std::endl;
+      exit(1);
+    }
+
+    // U_loop is U_{mu}
+    GaugeMat U_loop(Umu.Grid()), P(Umu.Grid());
     ComplexD out;
     int T = Umu.Grid()->GlobalDimensions()[3];
     int X = Umu.Grid()->GlobalDimensions()[0];
     int Y = Umu.Grid()->GlobalDimensions()[1];
     int Z = Umu.Grid()->GlobalDimensions()[2];
 
-    Ut = peekLorentz(Umu,3); //Select temporal direction
-    P = Ut;
-    for (int t=1;t<T;t++){ 
-      P = Gimpl::CovShiftForward(Ut,3,P);
+    // Number of sites in mu direction
+    int N_mu = Umu.Grid()->GlobalDimensions()[mu];
+
+    U_loop = peekLorentz(Umu, mu); //Select direction
+    P = U_loop;
+    for (int t=1;t<N_mu;t++){ 
+      P = Gimpl::CovShiftForward(U_loop,mu,P);
     }
    RealD norm = 1.0/(Nc*X*Y*Z*T);
    out = sum(trace(P))*norm;
    return out;   
-}
+  }  
+
+  /////////////////////////////////////////////////
+  // overload for temporal Polyakov loop
+  /////////////////////////////////////////////////
+  static ComplexD avgPolyakovLoop(const GaugeField &Umu) { 
+    return avgPolyakovLoop(Umu, 3);
+  }
 
   //////////////////////////////////////////////////
   // average over traced single links

HMC/FTHMC2p1f.cc

@@ -24,7 +24,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 #if Nc == 3
 #include <Grid/qcd/smearing/GaugeConfigurationMasked.h>
@@ -230,3 +234,4 @@ int main(int argc, char **argv)
 #endif
 } // main
 
+#endif

HMC/FTHMC2p1f_3GeV.cc

@@ -25,7 +25,11 @@ directory
 *************************************************************************************/
 /*  END LEGAL */
 
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 #if Nc == 3
 #include <Grid/qcd/smearing/GaugeConfigurationMasked.h>
@@ -231,5 +235,4 @@ int main(int argc, char **argv)
 #endif
 } // main
 
-
-
+#endif

HMC/HMC2p1f_3GeV.cc

@@ -24,7 +24,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 #if Nc == 3
 #include <Grid/qcd/smearing/GaugeConfigurationMasked.h>
@@ -230,5 +234,4 @@ int main(int argc, char **argv)
 #endif
 } // main
 
-
-
+#endif

HMC/Mobius2p1f.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 int main(int argc, char **argv) {
   using namespace Grid;
@@ -195,5 +199,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1fEOFA.cc

@@ -28,7 +28,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 #ifdef GRID_DEFAULT_PRECISION_DOUBLE
 #define MIXED_PRECISION
@@ -449,5 +453,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1fEOFA_F1.cc

@@ -28,7 +28,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 #ifdef GRID_DEFAULT_PRECISION_DOUBLE
 #define MIXED_PRECISION
@@ -442,5 +446,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1fIDSDRGparityEOFA_40ID.cc

@@ -28,7 +28,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 using namespace Grid;
 
@@ -918,3 +922,5 @@ int main(int argc, char **argv) {
   return 0;
 #endif
 } // main
+
+#endif

HMC/Mobius2p1fIDSDRGparityEOFA_48ID.cc

@@ -28,7 +28,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 using namespace Grid;
 
@@ -873,3 +877,5 @@ int main(int argc, char **argv) {
   return 0;
 #endif
 } // main
+
+#endif

HMC/Mobius2p1fRHMC.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 int main(int argc, char **argv) {
   using namespace Grid;
@@ -193,5 +197,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_DD_EOFA_96I_3level.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 NAMESPACE_BEGIN(Grid);
 
@@ -512,5 +516,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_DD_EOFA_96I_double.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 int main(int argc, char **argv) {
   using namespace Grid;
@@ -345,5 +349,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_DD_EOFA_96I_mixed.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 NAMESPACE_BEGIN(Grid);
 
@@ -516,5 +520,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_DD_EOFA_96I_mshift.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 NAMESPACE_BEGIN(Grid);
 
@@ -567,5 +571,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_DD_RHMC.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 int main(int argc, char **argv) {
   using namespace Grid;
@@ -263,5 +267,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_DD_RHMC_96I.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 int main(int argc, char **argv) {
   using namespace Grid;
@@ -417,5 +421,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_DD_RHMC_96I_mixed.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 NAMESPACE_BEGIN(Grid);
 
@@ -452,5 +456,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_EOFA_96I_hmc.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 NAMESPACE_BEGIN(Grid);
 
@@ -462,5 +466,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/Mobius2p1f_EOFA_96I_hmc_double.cc

@@ -27,7 +27,11 @@ See the full license in the file "LICENSE" in the top level distribution
 directory
 *************************************************************************************/
 /*  END LEGAL */
-#include <Grid/Grid.h>
+
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+#include<Grid/Grid.h>
 
 
 
@@ -264,5 +268,4 @@ int main(int argc, char **argv) {
   Grid_finalize();
 } // main
 
-
-
+#endif

HMC/disable_examples_without_instantiations.h

@@ -0,0 +1,16 @@
+#include <Grid/Grid.h>
+#pragma once
+
+
+#ifndef ENABLE_FERMION_INSTANTIATIONS
+#include <iostream>
+
+int main(void) {
+  std::cout << "This build of Grid was configured to exclude fermion instantiations, "
+	    << "which this example relies on. "
+	    << "Please reconfigure and rebuild Grid with --enable-fermion-instantiations"
+	    << "to run this example."
+	    << std::endl;
+  return 1;
+}
+#endif

benchmarks/Benchmark_ITT.cc

@@ -26,6 +26,9 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace Grid;
@@ -731,3 +734,5 @@ int main (int argc, char ** argv)
 
   Grid_finalize();
 }
+
+#endif

benchmarks/Benchmark_dwf.cc

@@ -20,6 +20,9 @@
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 #ifdef GRID_CUDA
 #define CUDA_PROFILE
@@ -439,3 +442,4 @@ void Benchmark(int Ls, Coordinate Dirichlet,bool sloppy)
   GRID_ASSERT(norm2(src_e)<1.0e-4);
   GRID_ASSERT(norm2(src_o)<1.0e-4);
 }
+#endif

benchmarks/Benchmark_dwf_fp32.cc

@@ -20,6 +20,10 @@
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 #ifdef GRID_CUDA
 #define CUDA_PROFILE
@@ -439,3 +443,5 @@ void Benchmark(int Ls, Coordinate Dirichlet,bool sloppy)
   GRID_ASSERT(norm2(src_e)<1.0e-4);
   GRID_ASSERT(norm2(src_o)<1.0e-4);
 }
+
+#endif

benchmarks/Benchmark_dwf_fp32_paranoid.cc

@@ -20,6 +20,9 @@
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 #ifdef GRID_CUDA
 #define CUDA_PROFILE
@@ -385,3 +388,5 @@ int main (int argc, char ** argv)
   Grid_finalize();
   exit(0);
 }
+
+#endif

benchmarks/Benchmark_dwf_sweep.cc

@@ -26,6 +26,9 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -238,5 +241,4 @@ void benchDw(std::vector<int> & latt4, int Ls, int threads,int report )
   }
 }
 
-
-
+#endif

benchmarks/Benchmark_gparity.cc

@@ -1,3 +1,7 @@
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+
 #include <Grid/Grid.h>
 #include <sstream>
 using namespace std;
@@ -155,3 +159,4 @@ int main (int argc, char ** argv)
   Grid_finalize();
 }
 
+#endif

benchmarks/Benchmark_halo.cc

@@ -20,6 +20,9 @@
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 #ifdef GRID_CUDA
 #define CUDA_PROFILE
@@ -129,3 +132,5 @@ int main (int argc, char ** argv)
   Grid_finalize();
   exit(0);
 }
+
+#endif

benchmarks/Benchmark_mooee.cc

@@ -26,6 +26,9 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -149,3 +152,5 @@ int main (int argc, char ** argv)
 
   Grid_finalize();
 }
+
+#endif

benchmarks/Benchmark_schur.cc

@@ -26,6 +26,9 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -172,5 +175,4 @@ void benchDw(std::vector<int> & latt4, int Ls)
   //  Dw.Report();
 }
 
-
-
+#endif

benchmarks/Benchmark_staggered.cc

@@ -26,6 +26,9 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -110,3 +113,5 @@ int main (int argc, char ** argv)
 
   Grid_finalize();
 }
+
+#endif

benchmarks/Benchmark_staggeredF.cc

@@ -26,6 +26,9 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -112,3 +115,5 @@ int main (int argc, char ** argv)
 
   Grid_finalize();
 }
+
+#endif

benchmarks/Benchmark_usqcd.cc

@@ -26,6 +26,10 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
+
 #include <Grid/Grid.h>
 #include <Grid/algorithms/blas/BatchedBlas.h>
 
@@ -978,3 +982,5 @@ int main (int argc, char ** argv)
   Grid_finalize();
   fclose(FP);
 }
+
+#endif

benchmarks/Benchmark_wilson.cc

@@ -26,6 +26,9 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -258,3 +261,5 @@ int main (int argc, char ** argv)
 
   Grid_finalize();
 }
+
+#endif

benchmarks/Benchmark_wilson_sweep.cc

@@ -19,6 +19,9 @@ Author: Richard Rollins <rprollins@users.noreply.github.com>
     See the full license in the file "LICENSE" in the top level distribution directory
 *************************************************************************************/
 /*  END LEGAL */
+#include "disable_benchmarks_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -161,3 +164,5 @@ void bench_wilson_eo (
   double flops = (single_site_flops * volume * ncall)/2.0;
   std::cout << flops/(t1-t0) << "\t\t";
 }
+
+#endif

benchmarks/disable_benchmarks_without_instantiations.h

@@ -0,0 +1,16 @@
+#include <Grid/Grid.h>
+
+#pragma once
+
+#ifndef ENABLE_FERMION_INSTANTIATIONS
+#include <iostream>
+
+int main(void) {
+  std::cout << "This build of Grid was configured to exclude fermion instantiations, "
+	    << "which this benchmark relies on. "
+	    << "Please reconfigure and rebuild Grid with --enable-fermion-instantiations"
+	    << "to run this benchmark."
+	    << std::endl;
+  return 1;
+}
+#endif

configure.ac

@@ -172,6 +172,12 @@ case ${ac_TRACING} in
 esac
 
 ############### fermions
+AC_ARG_ENABLE([fermion-instantiations],
+     [AS_HELP_STRING([--enable-fermion-instantiations=yes|no],[enable fermion instantiations])],
+     [ac_FERMION_REPS=${enable_fermion_instantiations}], [ac_FERMION_INSTANTIATIONS=yes])
+
+AM_CONDITIONAL(BUILD_FERMION_INSTANTIATIONS, [ test "${ac_FERMION_INSTANTIATIONS}X" == "yesX" ])
+
 AC_ARG_ENABLE([fermion-reps],
      [AS_HELP_STRING([--enable-fermion-reps=yes|no],[enable extra fermion representation support])],
      [ac_FERMION_REPS=${enable_fermion_reps}], [ac_FERMION_REPS=yes])
@@ -194,6 +200,9 @@ AM_CONDITIONAL(BUILD_ZMOBIUS, [ test "${ac_ZMOBIUS}X" == "yesX" ])
 case ${ac_FERMION_REPS} in
    yes) AC_DEFINE([ENABLE_FERMION_REPS],[1],[non QCD fermion reps]);;
 esac
+case ${ac_FERMION_INSTANTIATIONS} in
+   yes) AC_DEFINE([ENABLE_FERMION_INSTANTIATIONS],[1],[enable fermions]);;
+esac
 case ${ac_GPARITY} in
    yes) AC_DEFINE([ENABLE_GPARITY],[1],[fermion actions with GPARITY BCs]);;
 esac

examples/Example_Mobius_spectrum.cc

@@ -3,6 +3,9 @@
  * without regression / tests being applied
  */
 
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -310,5 +313,4 @@ int main (int argc, char ** argv)
   Grid_finalize();
 }
 
-
-
+#endif

examples/Example_christoph.cc

@@ -3,6 +3,9 @@
  * without regression / tests being applied
  */
 
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -432,5 +435,4 @@ int main (int argc, char ** argv)
   Grid_finalize();
 }
 
-
-
+#endif

examples/Example_wall_wall_3pt.cc

@@ -3,6 +3,9 @@
  * without regression / tests being applied
  */
 
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -535,5 +538,4 @@ int main (int argc, char ** argv)
   Grid_finalize();
 }
 
-
-
+#endif

examples/Example_wall_wall_spectrum.cc

@@ -3,6 +3,9 @@
  * without regression / tests being applied
  */
 
+#include "disable_examples_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -429,5 +432,4 @@ int main (int argc, char ** argv)
   Grid_finalize();
 }
 
-
-
+#endif

examples/disable_examples_without_instantiations.h

@@ -0,0 +1,15 @@
+#include <Grid/Grid.h>
+#pragma once
+
+#ifndef ENABLE_FERMION_INSTANTIATIONS
+#include <iostream>
+
+int main(void) {
+  std::cout << "This build of Grid was configured to exclude fermion instantiations, "
+	    << "which this example relies on. "
+	    << "Please reconfigure and rebuild Grid with --enable-fermion-instantiations"
+	    << "to run this example."
+	    << std::endl;
+  return 1;
+}
+#endif

tests/Test_cayley_even_odd_vec.cc

@@ -25,6 +25,9 @@ Author: Peter Boyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_tests_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -273,8 +276,6 @@ void  TestWhat(What & Ddwf,
 
   err = phi-chi;
   std::cout<<GridLogMessage << "norm diff   "<< norm2(err)<< std::endl;
-
-  
 }
 
-
+#endif

tests/Test_compressed_lanczos_hot_start.cc

@@ -30,6 +30,9 @@ Author: Peter Boyle <paboyle@ph.ed.ac.uk>
  *  Reimplement the badly named "multigrid" lanczos as compressed Lanczos using the features 
  *  in Grid that were intended to be used to support blocked Aggregates, from
  */
+#include "disable_tests_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 #include <Grid/algorithms/iterative/ImplicitlyRestartedLanczos.h>
 #include <Grid/algorithms/iterative/LocalCoherenceLanczos.h>
@@ -256,3 +259,4 @@ int main (int argc, char ** argv) {
   Grid_finalize();
 }
 
+#endif

tests/Test_dwf_dslash_repro.cc

@@ -25,6 +25,9 @@ Author: Peter Boyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_tests_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -237,3 +240,5 @@ int main (int argc, char ** argv)
   
   Grid_finalize();
 }
+
+#endif

tests/Test_dwf_mixedcg_prec.cc

@@ -25,6 +25,9 @@ Author: Peter Boyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_tests_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -222,3 +225,5 @@ int main (int argc, char ** argv)
   
   Grid_finalize();
 }
+
+#endif

tests/Test_dwf_mixedcg_prec_halfcomms.cc

@@ -25,6 +25,9 @@ Author: Peter Boyle <paboyle@ph.ed.ac.uk>
     See the full license in the file "LICENSE" in the top level distribution directory
     *************************************************************************************/
     /*  END LEGAL */
+#include "disable_tests_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
+
 #include <Grid/Grid.h>
 
 using namespace std;
@@ -118,3 +121,4 @@ int main (int argc, char ** argv)
   Grid_finalize();
 }
 #endif
+#endif

tests/Test_meson_field.cc

@@ -24,6 +24,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 See the full license in the file "LICENSE" in the top level distribution directory
 *************************************************************************************/
+#include "disable_tests_without_instantiations.h"
+#ifdef ENABLE_FERMION_INSTANTIATIONS
 
 #include <Grid/Grid.h>
 #include <Grid/qcd/utils/A2Autils.h>
@@ -157,3 +159,5 @@ int main(int argc, char *argv[])
   
   return EXIT_SUCCESS;
 }
+
+#endif

tests/debug/Test_general_coarse_hdcg.cc

@@ -128,6 +128,10 @@ int main (int argc, char ** argv)
   typedef HermOpAdaptor<LatticeFermionD> HermFineMatrix;
   HermFineMatrix FineHermOp(HermOpEO);
 
+  LatticeFermionD src(FrbGrid); 
+  src = ComplexD(1.0);
+  PowerMethod<LatticeFermionD>       PM;   PM(HermOpEO,src);
+
   ////////////////////////////////////////////////////////////
   ///////////// Coarse basis and Little Dirac Operator ///////
   ////////////////////////////////////////////////////////////
@@ -150,7 +154,7 @@ int main (int argc, char ** argv)
   std::cout << "**************************************"<<std::endl;
   std::cout << "Create Subspace"<<std::endl;
   std::cout << "**************************************"<<std::endl;
-  Aggregates.CreateSubspaceChebyshevNew(RNG5,HermOpEO,95.); 
+  Aggregates.CreateSubspaceChebyshev(RNG5,HermOpEO,nbasis,35.,0.01,500);// <== last run
 
   std::cout << "**************************************"<<std::endl;
   std::cout << "Refine Subspace"<<std::endl;
@@ -185,7 +189,7 @@ int main (int argc, char ** argv)
   std::cout << "**************************************"<<std::endl;
 
   typedef HermitianLinearOperator<MultiGeneralCoarsenedMatrix_t,CoarseVector> MrhsHermMatrix;
-  Chebyshev<CoarseVector>      IRLCheby(0.05,40.0,101);  // 1 iter
+  Chebyshev<CoarseVector>      IRLCheby(0.01,16.0,201);  // 1 iter
   MrhsHermMatrix MrhsCoarseOp     (mrhs);
 
   CoarseVector pm_src(CoarseMrhs);
@@ -193,10 +197,10 @@ int main (int argc, char ** argv)
   PowerMethod<CoarseVector>       cPM;
   cPM(MrhsCoarseOp,pm_src);
 
-  int Nk=nrhs;
-  int Nm=Nk*3;
-  //  int Nk=36;
-  //  int Nm=144;
+  //  int Nk=16;
+  //  int Nm=Nk*3;
+  int Nk=32;
+  int Nm=128;
   int Nstop=Nk;
   int Nconv_test_interval=1;
   
@@ -210,7 +214,7 @@ int main (int argc, char ** argv)
 							  nrhs,
 							  Nk,
 							  Nm,
-							  1e-4,10);
+							  1e-4,100);
 
   int Nconv;
   std::vector<RealD>            eval(Nm);
@@ -231,8 +235,6 @@ int main (int argc, char ** argv)
   std::cout << "**************************************"<<std::endl;
   std::cout << " Recompute coarse evecs  "<<std::endl;
   std::cout << "**************************************"<<std::endl;
-  evec.resize(Nm,Coarse5d);
-  eval.resize(Nm);
   for(int r=0;r<nrhs;r++){
     random(CRNG,c_src[r]);
   }
@@ -243,7 +245,7 @@ int main (int argc, char ** argv)
   // Deflation guesser object
   ///////////////////////
   std::cout << "**************************************"<<std::endl;
-  std::cout << " Reimport coarse evecs  "<<std::endl;
+  std::cout << " Reimport coarse evecs "<<evec.size()<<" "<<eval.size()<<std::endl;
   std::cout << "**************************************"<<std::endl;
   MultiRHSDeflation<CoarseVector> MrhsGuesser;
   MrhsGuesser.ImportEigenBasis(evec,eval);
@@ -252,9 +254,11 @@ int main (int argc, char ** argv)
   // Extra HDCG parameters
   //////////////////////////
   int maxit=3000;
-  ConjugateGradient<CoarseVector>  CG(2.0e-1,maxit,false);
-  RealD lo=2.0;
-  int ord = 9;
+  //  ConjugateGradient<CoarseVector>  CG(2.0e-1,maxit,false);
+  //  ConjugateGradient<CoarseVector>  CG(1.0e-2,maxit,false);
+  ConjugateGradient<CoarseVector>  CG(5.0e-2,maxit,false);
+  RealD lo=0.2;
+  int ord = 7;
 
   DoNothingGuesser<CoarseVector> DoNothing;
   HPDSolver<CoarseVector> HPDSolveMrhs(MrhsCoarseOp,CG,DoNothing);
@@ -300,6 +304,19 @@ int main (int argc, char ** argv)
     ConjugateGradient<LatticeFermionD>  CGfine(1.0e-8,30000,false);
     CGfine(HermOpEO, src, result);
   }
+  {
+    std::cout << "**************************************"<<std::endl;
+    std::cout << "Calling MdagM CG"<<std::endl;
+    std::cout << "**************************************"<<std::endl;
+      
+    LatticeFermion result(FGrid); result=Zero();
+    LatticeFermion    src(FGrid); random(RNG5,src);
+    result=Zero();
+
+    MdagMLinearOperator<MobiusFermionD, LatticeFermionD> HermOp(Ddwf);
+    ConjugateGradient<LatticeFermionD>  CGfine(1.0e-8,30000,false);
+    CGfine(HermOp, src, result);
+  }
 #endif  
   Grid_finalize();
   return 0;

tests/debug/Test_general_coarse_pvdagm.cc

@@ -368,7 +368,10 @@ int main (int argc, char ** argv)
   TrivialPrecon<CoarseVector> simple;
   NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOpPV);
   //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-4, 100, LinOpCoarse,simple,10,10); 
-  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(3.0e-2, 100, LinOpCoarse,simple,10,10); 
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(3.0e-2, 100, LinOpCoarse,simple,12,12);  // 35 outer
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(5.0e-2, 100, LinOpCoarse,simple,12,12);  // 36 outer, 12s
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-1, 100, LinOpCoarse,simple,12,12);  // 36 ; 11s   
+  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(3.0e-1, 100, LinOpCoarse,simple,12,12);     
   L2PGCR.Level(3);
   c_res=Zero();
   L2PGCR(c_src,c_res);
@@ -400,7 +403,7 @@ int main (int argc, char ** argv)
 			    LinOpCoarse,
 			    L2PGCR);
   
-  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,1000,PVdagM,TwoLevelPrecon,16,16);
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,100,PVdagM,TwoLevelPrecon,10,10);
   L1PGCR.Level(1);
 
   f_res=Zero();

tests/debug/Test_general_coarse_pvdagm_svd.cc

@@ -0,0 +1,493 @@
+/*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_padded_cell.cc
+
+    Copyright (C) 2023
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+#include <Grid/lattice/PaddedCell.h>
+#include <Grid/stencil/GeneralLocalStencil.h>
+
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidual.h>
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
+#include <Grid/algorithms/iterative/BiCGSTAB.h>
+
+using namespace std;
+using namespace Grid;
+
+template<class Matrix,class Field>
+class PVdagMLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+public:
+  PVdagMLinearOperator(Matrix &Mat,Matrix &PV): _Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    //    std::cout << GridLogMessage<< "Op: PVdag M "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout << GridLogMessage<<"AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _PV.M(in,tmp);
+    _Mat.Mdag(tmp,out);
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){
+    assert(0);
+  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout <<GridLogMessage<< "HermOp: Mdag PV PVdag M"<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+    //    std::cout << "HermOp done "<<norm2(out)<<std::endl;
+  }
+};
+template<class Matrix,class Field>
+class MdagPVLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+public:
+  MdagPVLinearOperator(Matrix &Mat,Matrix &PV): _Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    Field tmp(in.Grid());
+    //    std::cout <<GridLogMessage<< "Op: PVdag M "<<std::endl;
+    _PV.M(in,tmp);
+    _Mat.Mdag(tmp,out);
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout <<GridLogMessage<< "AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){
+    assert(0);
+  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout << GridLogMessage<<"HermOp: PVdag M Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+    //    std::cout << "HermOp done "<<norm2(out)<<std::endl;
+  }
+};
+template<class Matrix,class Field>
+class ShiftedPVdagMLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+  RealD shift;
+public:
+  ShiftedPVdagMLinearOperator(RealD _shift,Matrix &Mat,Matrix &PV): shift(_shift),_Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    //    std::cout << "Op: PVdag M "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+    out = out + shift * in;
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout << "AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _PV.M(tmp,out);
+    _Mat.Mdag(in,tmp);
+    out = out + shift * in;
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){    assert(0);  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout << "HermOp: Mdag PV PVdag M"<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+  }
+};
+template<class Fobj,class CComplex,int nbasis>
+class MGPreconditionerSVD : public LinearFunction< Lattice<Fobj> > {
+public:
+  using LinearFunction<Lattice<Fobj> >::operator();
+
+  typedef Aggregation<Fobj,CComplex,nbasis> Aggregates;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::FineField    FineField;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseVector CoarseVector;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseMatrix CoarseMatrix;
+  typedef LinearOperatorBase<FineField>                            FineOperator;
+  typedef LinearFunction    <FineField>                            FineSmoother;
+  typedef LinearOperatorBase<CoarseVector>                         CoarseOperator;
+  typedef LinearFunction    <CoarseVector>                         CoarseSolver;
+  Aggregates     & _FineToCoarse;
+  Aggregates     & _CoarseToFine;
+  FineOperator   & _FineOperator;
+  FineSmoother   & _PreSmoother;
+  FineSmoother   & _PostSmoother;
+  CoarseOperator & _CoarseOperator;
+  CoarseSolver   & _CoarseSolve;
+
+  int    level;  void Level(int lv) {level = lv; };
+
+  MGPreconditionerSVD(Aggregates &FtoC,
+		      Aggregates &CtoF,
+		      FineOperator &Fine,
+		      FineSmoother &PreSmoother,
+		      FineSmoother &PostSmoother,
+		      CoarseOperator &CoarseOperator_,
+		      CoarseSolver &CoarseSolve_)
+    : _FineToCoarse(FtoC),
+      _CoarseToFine(CtoF),
+      _FineOperator(Fine),
+      _PreSmoother(PreSmoother),
+      _PostSmoother(PostSmoother),
+      _CoarseOperator(CoarseOperator_),
+      _CoarseSolve(CoarseSolve_),
+      level(1)  {  }
+
+  virtual void operator()(const FineField &in, FineField & out) 
+  {
+    GridBase *CoarseGrid = _FineToCoarse.CoarseGrid;
+    //    auto CoarseGrid = _CoarseOperator.Grid();
+    CoarseVector Csrc(CoarseGrid);
+    CoarseVector Csol(CoarseGrid);
+    FineField vec1(in.Grid());
+    FineField vec2(in.Grid());
+
+    std::cout<<GridLogMessage << "Calling PreSmoother " <<std::endl;
+
+    //    std::cout<<GridLogMessage << "Calling PreSmoother input residual "<<norm2(in) <<std::endl;
+    double t;
+    // Fine Smoother
+    //    out = in;
+    out = Zero();
+    t=-usecond();
+    _PreSmoother(in,out);
+    t+=usecond();
+
+    std::cout<<GridLogMessage << "PreSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Update the residual
+    _FineOperator.Op(out,vec1);  sub(vec1, in ,vec1);   
+    //    std::cout<<GridLogMessage <<"Residual-1 now " <<norm2(vec1)<<std::endl;
+
+    // Fine to Coarse 
+    t=-usecond();
+    _FineToCoarse.ProjectToSubspace  (Csrc,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Project to coarse took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse correction
+    t=-usecond();
+    Csol = Zero();
+    _CoarseSolve(Csrc,Csol);
+    //Csol=Zero();
+    t+=usecond();
+    std::cout<<GridLogMessage << "Coarse solve took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse to Fine
+    t=-usecond();  
+    //    _CoarseOperator.PromoteFromSubspace(_Aggregates,Csol,vec1);
+    _CoarseToFine.PromoteFromSubspace(Csol,vec1); 
+    add(out,out,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Promote to this level took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Residual
+    _FineOperator.Op(out,vec1);  sub(vec1 ,in , vec1);  
+    //    std::cout<<GridLogMessage <<"Residual-2 now " <<norm2(vec1)<<std::endl;
+
+    // Fine Smoother
+    t=-usecond();
+    //    vec2=vec1;
+    vec2=Zero();
+    _PostSmoother(vec1,vec2);
+    t+=usecond();
+    std::cout<<GridLogMessage << "PostSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    add( out,out,vec2);
+    std::cout<<GridLogMessage << "Done " <<std::endl;
+  }
+};
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=16;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+
+  GridCartesian         * FGrid   = SpaceTimeGrid::makeFiveDimGrid(Ls,UGrid);
+  GridRedBlackCartesian * FrbGrid = SpaceTimeGrid::makeFiveDimRedBlackGrid(Ls,UGrid);
+
+  // Construct a coarsened grid
+  Coordinate clatt = GridDefaultLatt();
+  for(int d=0;d<clatt.size();d++){
+    clatt[d] = clatt[d]/2;
+    //    clatt[d] = clatt[d]/4;
+  }
+  GridCartesian *Coarse4d =  SpaceTimeGrid::makeFourDimGrid(clatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());;
+  GridCartesian *Coarse5d =  SpaceTimeGrid::makeFiveDimGrid(1,Coarse4d);
+
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> seeds5({5,6,7,8});
+  std::vector<int> cseeds({5,6,7,8});
+  GridParallelRNG          RNG5(FGrid);   RNG5.SeedFixedIntegers(seeds5);
+  GridParallelRNG          RNG4(UGrid);   RNG4.SeedFixedIntegers(seeds4);
+  GridParallelRNG          CRNG(Coarse5d);CRNG.SeedFixedIntegers(cseeds);
+
+  LatticeFermion    src(FGrid); random(RNG5,src);
+  LatticeFermion result(FGrid); result=Zero();
+  LatticeFermion    ref(FGrid); ref=Zero();
+  LatticeFermion    tmp(FGrid);
+  LatticeFermion    err(FGrid);
+  LatticeGaugeField Umu(UGrid);
+
+  FieldMetaData header;
+  std::string file("ckpoint_lat.4000");
+  NerscIO::readConfiguration(Umu,header,file);
+  
+  RealD mass=0.01;
+  RealD M5=1.8;
+
+  DomainWallFermionD Ddwf(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,mass,M5);
+  DomainWallFermionD Dpv(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,1.0,M5);
+
+  const int nbasis = 30;
+  const int cb = 0 ;
+
+
+  NextToNearestStencilGeometry5D geom(Coarse5d);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+
+  typedef PVdagMLinearOperator<DomainWallFermionD,LatticeFermionD> PVdagM_t;
+  typedef MdagPVLinearOperator<DomainWallFermionD,LatticeFermionD> MdagPV_t;
+  typedef ShiftedPVdagMLinearOperator<DomainWallFermionD,LatticeFermionD> ShiftedPVdagM_t;
+  PVdagM_t PVdagM(Ddwf,Dpv);
+  MdagPV_t MdagPV(Ddwf,Dpv);
+  //  ShiftedPVdagM_t ShiftedPVdagM(2.0,Ddwf,Dpv); // 355
+  //  ShiftedPVdagM_t ShiftedPVdagM(1.0,Ddwf,Dpv); // 246
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.5,Ddwf,Dpv); // 183
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 145
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 134
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 127 -- NULL space via inverse iteration
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 57 -- NULL space via inverse iteration; 3 iterations
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 57 , tighter inversion
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // nbasis 20 -- 49 iters
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // nbasis 20 -- 70 iters; asymmetric 
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 58; Loosen coarse, tighten fine
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 56 ... 
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 51 ...  with 24 vecs
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 31 ...  with 24 vecs and 2^4 blocking
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 43 ...  with 16 vecs and 2^4 blocking, sloppier
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 35  ...  with 20 vecs and 2^4 blocking
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 35  ...  with 20 vecs and 2^4 blocking, looser coarse
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 64  ...  with 20 vecs, Christoph setup, and 2^4 blocking, looser coarse
+  ShiftedPVdagM_t ShiftedPVdagM(0.01,Ddwf,Dpv); // 
+
+
+  // Run power method on HOA??
+  PowerMethod<LatticeFermion>       PM;
+  //  PM(PVdagM,src);
+  //  PM(MdagPV,src);
+ 
+  // Warning: This routine calls PVdagM.Op, not PVdagM.HermOp
+  typedef Aggregation<vSpinColourVector,vTComplex,nbasis> Subspace;
+  Subspace V(Coarse5d,FGrid,cb);
+  Subspace U(Coarse5d,FGrid,cb);
+
+  // Breeds right singular vectors with call to HermOp (V)
+  V.CreateSubspaceChebyshev(RNG5,PVdagM,
+			    nbasis,
+			    4000.0,0.003,
+			    500);
+
+  // Breeds left singular vectors with call to HermOp (U)
+  //  U.CreateSubspaceChebyshev(RNG5,PVdagM,
+  U.CreateSubspaceChebyshev(RNG5,MdagPV,
+			    nbasis,
+			    4000.0,0.003,
+			    500);
+  
+  typedef Aggregation<vSpinColourVector,vTComplex,2*nbasis> CombinedSubspace;
+  CombinedSubspace CombinedUV(Coarse5d,FGrid,cb);
+  for(int b=0;b<nbasis;b++){
+    CombinedUV.subspace[b]        = V.subspace[b];
+    CombinedUV.subspace[b+nbasis] = U.subspace[b];
+  }
+
+  int bl, br;
+  std::cout <<" <V| PVdagM| V> " <<std::endl;
+  for(bl=0;bl<nbasis;bl++){
+  for(br=0;br<nbasis;br++){
+    PVdagM.Op(V.subspace[br],src);
+    std::cout <<bl<<" "<<br<<"\t"<<innerProduct(V.subspace[bl],src)<<std::endl;
+  }}
+  std::cout <<" <V| PVdagM| U> " <<std::endl;
+  for(bl=0;bl<nbasis;bl++){
+  for(br=0;br<nbasis;br++){
+    PVdagM.Op(U.subspace[br],src);
+    std::cout <<bl<<" "<<br<<"\t"<<innerProduct(V.subspace[bl],src)<<std::endl;
+  }}
+  std::cout <<" <U| PVdagM| V> " <<std::endl;
+  for(bl=0;bl<nbasis;bl++){
+  for(br=0;br<nbasis;br++){
+    PVdagM.Op(V.subspace[br],src);
+    std::cout <<bl<<" "<<br<<"\t"<<innerProduct(U.subspace[bl],src)<<std::endl;
+  }}
+  std::cout <<" <U| PVdagM| U> " <<std::endl;
+  for(bl=0;bl<nbasis;bl++){
+  for(br=0;br<nbasis;br++){
+    PVdagM.Op(U.subspace[br],src);
+    std::cout <<bl<<" "<<br<<"\t"<<innerProduct(U.subspace[bl],src)<<std::endl;
+  }}
+
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,nbasis> LittleDiracOperatorV;
+  typedef LittleDiracOperatorV::CoarseVector CoarseVectorV;
+  
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,2*nbasis> LittleDiracOperator;
+  typedef LittleDiracOperator::CoarseVector CoarseVector;
+
+  V.Orthogonalise();
+  for(int b =0 ; b<nbasis;b++){
+    CoarseVectorV c_src (Coarse5d);
+    V.ProjectToSubspace  (c_src,U.subspace[b]);
+    V.PromoteFromSubspace(c_src,src);
+    std::cout << " Completeness of U in V ["<< b<<"] "<< std::sqrt(norm2(src)/norm2(U.subspace[b]))<<std::endl;
+  }
+  
+  CoarseVector c_src (Coarse5d);
+  CoarseVector c_res (Coarse5d);
+  CoarseVector c_proj(Coarse5d);
+  LittleDiracOperator LittleDiracOpPV(geom,FGrid,Coarse5d);
+  LittleDiracOpPV.CoarsenOperator(PVdagM,CombinedUV,CombinedUV);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"Testing coarsened operator "<<std::endl;
+  
+  Complex one(1.0);
+  c_src = one;  // 1 in every element for vector 1.
+
+  blockPromote(c_src,err,CombinedUV.subspace);
+
+  LatticeFermion prom(FGrid);
+  prom=Zero();
+  for(int b=0;b<nbasis*2;b++){
+    prom=prom+CombinedUV.subspace[b];
+  }
+
+  std::cout<<GridLogMessage<<"c_src "<<norm2(c_src)<<std::endl;
+  std::cout<<GridLogMessage<<"prom  "<<norm2(prom)<<std::endl;
+
+  PVdagM.Op(prom,tmp);
+  blockProject(c_proj,tmp,CombinedUV.subspace);
+  std::cout<<GridLogMessage<<" Called Big Dirac Op "<<norm2(tmp)<<std::endl;
+
+  LittleDiracOpPV.M(c_src,c_res);
+  std::cout<<GridLogMessage<<" Called Little Dirac Op c_src "<< norm2(c_src) << "  c_res "<< norm2(c_res) <<std::endl;
+
+  std::cout<<GridLogMessage<<"Little dop : "<<norm2(c_res)<<std::endl;
+
+  std::cout<<GridLogMessage<<"Big dop in subspace : "<<norm2(c_proj)<<std::endl;
+
+  c_proj = c_proj - c_res;
+  std::cout<<GridLogMessage<<" ldop error: "<<norm2(c_proj)<<std::endl;
+
+
+  /**********
+   * Some solvers
+   **********
+   */
+
+  ///////////////////////////////////////
+  // Coarse grid solver test
+  ///////////////////////////////////////
+
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Coarse Grid Solve -- Level 3 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<CoarseVector> simple;
+  NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOpPV);
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-4, 100, LinOpCoarse,simple,10,10); 
+  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-2, 10, LinOpCoarse,simple,20,20); 
+  L2PGCR.Level(3);
+  c_res=Zero();
+  L2PGCR(c_src,c_res);
+
+  ////////////////////////////////////////
+  // Fine grid smoother
+  ////////////////////////////////////////
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Fine Grid Smoother -- Level 2 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<LatticeFermionD> simple_fine;
+  //  NonHermitianLinearOperator<PVdagM_t,LatticeFermionD> LinOpSmooth(PVdagM);
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> SmootherGCR(0.01,1,ShiftedPVdagM,simple_fine,16,16);
+  SmootherGCR.Level(2);
+  
+  LatticeFermionD f_src(FGrid);
+  LatticeFermionD f_res(FGrid);
+
+  f_src = one;  // 1 in every element for vector 1.
+  f_res=Zero();
+  SmootherGCR(f_src,f_res);
+
+  typedef MGPreconditionerSVD<vSpinColourVector,  vTComplex,nbasis*2> TwoLevelMG;
+
+  TwoLevelMG TwoLevelPrecon(CombinedUV,CombinedUV,
+			    PVdagM,
+			    simple_fine,
+			    SmootherGCR,
+			    LinOpCoarse,
+			    L2PGCR);
+  
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,1000,PVdagM,TwoLevelPrecon,20,20);
+  L1PGCR.Level(1);
+
+  f_res=Zero();
+  L1PGCR(f_src,f_res);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage << "Done "<< std::endl;
+
+  Grid_finalize();
+  return 0;
+}

tests/debug/Test_general_coarse_pvdagm_svd_cg.cc

@@ -0,0 +1,492 @@
+/*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_padded_cell.cc
+
+    Copyright (C) 2023
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+#include <Grid/lattice/PaddedCell.h>
+#include <Grid/stencil/GeneralLocalStencil.h>
+
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidual.h>
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
+#include <Grid/algorithms/iterative/BiCGSTAB.h>
+
+using namespace std;
+using namespace Grid;
+
+template<class Matrix,class Field>
+class PVdagMLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+public:
+  PVdagMLinearOperator(Matrix &Mat,Matrix &PV): _Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    //    std::cout << GridLogMessage<< "Op: PVdag M "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout << GridLogMessage<<"AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _PV.M(in,tmp);
+    _Mat.Mdag(tmp,out);
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){
+    HermOp(in,out);
+    ComplexD dot = innerProduct(in,out);
+    n1=real(dot);
+    n2=norm2(out);
+  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout <<GridLogMessage<< "HermOp: Mdag PV PVdag M"<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+    //    std::cout << "HermOp done "<<norm2(out)<<std::endl;
+  }
+};
+template<class Matrix,class Field>
+class MdagPVLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+public:
+  MdagPVLinearOperator(Matrix &Mat,Matrix &PV): _Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    Field tmp(in.Grid());
+    //    std::cout <<GridLogMessage<< "Op: PVdag M "<<std::endl;
+    _PV.M(in,tmp);
+    _Mat.Mdag(tmp,out);
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout <<GridLogMessage<< "AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){
+    ComplexD dot = innerProduct(in,out);
+    n1=real(dot);
+    n2=norm2(out);
+  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout << GridLogMessage<<"HermOp: PVdag M Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+    //    std::cout << "HermOp done "<<norm2(out)<<std::endl;
+  }
+};
+template<class Matrix,class Field>
+class ShiftedPVdagMLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+  RealD shift;
+public:
+  ShiftedPVdagMLinearOperator(RealD _shift,Matrix &Mat,Matrix &PV): shift(_shift),_Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    //    std::cout << "Op: PVdag M "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+    out = out + shift * in;
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout << "AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _PV.M(tmp,out);
+    _Mat.Mdag(in,tmp);
+    out = out + shift * in;
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){    assert(0);  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout << "HermOp: Mdag PV PVdag M"<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+  }
+};
+template<class Fobj,class CComplex,int nbasis>
+class MGPreconditionerSVD : public LinearFunction< Lattice<Fobj> > {
+public:
+  using LinearFunction<Lattice<Fobj> >::operator();
+
+  typedef Aggregation<Fobj,CComplex,nbasis> Aggregates;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::FineField    FineField;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseVector CoarseVector;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseMatrix CoarseMatrix;
+  typedef LinearOperatorBase<FineField>                            FineOperator;
+  typedef LinearFunction    <FineField>                            FineSmoother;
+  typedef LinearOperatorBase<CoarseVector>                         CoarseOperator;
+  typedef LinearFunction    <CoarseVector>                         CoarseSolver;
+  Aggregates     & _FineToCoarse;
+  Aggregates     & _CoarseToFine;
+  FineOperator   & _FineOperator;
+  FineSmoother   & _PreSmoother;
+  FineSmoother   & _PostSmoother;
+  CoarseOperator & _CoarseOperator;
+  CoarseSolver   & _CoarseSolve;
+
+  int    level;  void Level(int lv) {level = lv; };
+
+  MGPreconditionerSVD(Aggregates &FtoC,
+		      Aggregates &CtoF,
+		      FineOperator &Fine,
+		      FineSmoother &PreSmoother,
+		      FineSmoother &PostSmoother,
+		      CoarseOperator &CoarseOperator_,
+		      CoarseSolver &CoarseSolve_)
+    : _FineToCoarse(FtoC),
+      _CoarseToFine(CtoF),
+      _FineOperator(Fine),
+      _PreSmoother(PreSmoother),
+      _PostSmoother(PostSmoother),
+      _CoarseOperator(CoarseOperator_),
+      _CoarseSolve(CoarseSolve_),
+      level(1)  {  }
+
+  virtual void operator()(const FineField &in, FineField & out) 
+  {
+    GridBase *CoarseGrid = _FineToCoarse.CoarseGrid;
+    //    auto CoarseGrid = _CoarseOperator.Grid();
+    CoarseVector Csrc(CoarseGrid);
+    CoarseVector Csol(CoarseGrid);
+    FineField vec1(in.Grid());
+    FineField vec2(in.Grid());
+
+    std::cout<<GridLogMessage << "Calling PreSmoother " <<std::endl;
+
+    //    std::cout<<GridLogMessage << "Calling PreSmoother input residual "<<norm2(in) <<std::endl;
+    double t;
+    // Fine Smoother
+    //    out = in;
+    out = Zero();
+    t=-usecond();
+    _PreSmoother(in,out);
+    t+=usecond();
+
+    std::cout<<GridLogMessage << "PreSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Update the residual
+    _FineOperator.Op(out,vec1);  sub(vec1, in ,vec1);   
+    //    std::cout<<GridLogMessage <<"Residual-1 now " <<norm2(vec1)<<std::endl;
+
+    // Fine to Coarse 
+    t=-usecond();
+    _FineToCoarse.ProjectToSubspace  (Csrc,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Project to coarse took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse correction
+    t=-usecond();
+    Csol = Zero();
+    _CoarseSolve(Csrc,Csol);
+    //Csol=Zero();
+    t+=usecond();
+    std::cout<<GridLogMessage << "Coarse solve took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse to Fine
+    t=-usecond();  
+    //    _CoarseOperator.PromoteFromSubspace(_Aggregates,Csol,vec1);
+    _CoarseToFine.PromoteFromSubspace(Csol,vec1); 
+    add(out,out,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Promote to this level took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Residual
+    _FineOperator.Op(out,vec1);  sub(vec1 ,in , vec1);  
+    //    std::cout<<GridLogMessage <<"Residual-2 now " <<norm2(vec1)<<std::endl;
+
+    // Fine Smoother
+    t=-usecond();
+    //    vec2=vec1;
+    vec2=Zero();
+    _PostSmoother(vec1,vec2);
+    t+=usecond();
+    std::cout<<GridLogMessage << "PostSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    add( out,out,vec2);
+    std::cout<<GridLogMessage << "Done " <<std::endl;
+  }
+};
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=16;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+
+  GridCartesian         * FGrid   = SpaceTimeGrid::makeFiveDimGrid(Ls,UGrid);
+  GridRedBlackCartesian * FrbGrid = SpaceTimeGrid::makeFiveDimRedBlackGrid(Ls,UGrid);
+
+  // Construct a coarsened grid
+  Coordinate clatt = GridDefaultLatt();
+  for(int d=0;d<clatt.size();d++){
+    clatt[d] = clatt[d]/2;
+    //    clatt[d] = clatt[d]/4;
+  }
+  GridCartesian *Coarse4d =  SpaceTimeGrid::makeFourDimGrid(clatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());;
+  GridCartesian *Coarse5d =  SpaceTimeGrid::makeFiveDimGrid(1,Coarse4d);
+
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> seeds5({5,6,7,8});
+  std::vector<int> cseeds({5,6,7,8});
+  GridParallelRNG          RNG5(FGrid);   RNG5.SeedFixedIntegers(seeds5);
+  GridParallelRNG          RNG4(UGrid);   RNG4.SeedFixedIntegers(seeds4);
+  GridParallelRNG          CRNG(Coarse5d);CRNG.SeedFixedIntegers(cseeds);
+
+  LatticeFermion    src(FGrid); random(RNG5,src);
+  LatticeFermion result(FGrid); result=Zero();
+  LatticeFermion    ref(FGrid); ref=Zero();
+  LatticeFermion    tmp(FGrid);
+  LatticeFermion    err(FGrid);
+  LatticeGaugeField Umu(UGrid);
+
+  FieldMetaData header;
+  std::string file("ckpoint_lat.4000");
+  NerscIO::readConfiguration(Umu,header,file);
+  
+  RealD mass=0.01;
+  RealD M5=1.8;
+
+  DomainWallFermionD Ddwf(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,mass,M5);
+  DomainWallFermionD Dpv(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,1.0,M5);
+
+  const int nbasis = 20;
+  const int cb = 0 ;
+
+
+  NextToNearestStencilGeometry5D geom(Coarse5d);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+
+  typedef PVdagMLinearOperator<DomainWallFermionD,LatticeFermionD> PVdagM_t;
+  typedef MdagPVLinearOperator<DomainWallFermionD,LatticeFermionD> MdagPV_t;
+  typedef ShiftedPVdagMLinearOperator<DomainWallFermionD,LatticeFermionD> ShiftedPVdagM_t;
+  PVdagM_t PVdagM(Ddwf,Dpv);
+  MdagPV_t MdagPV(Ddwf,Dpv);
+  //  ShiftedPVdagM_t ShiftedPVdagM(2.0,Ddwf,Dpv); // 355
+  //  ShiftedPVdagM_t ShiftedPVdagM(1.0,Ddwf,Dpv); // 246
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.5,Ddwf,Dpv); // 183
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 145
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 134
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 127 -- NULL space via inverse iteration
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 57 -- NULL space via inverse iteration; 3 iterations
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 57 , tighter inversion
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // nbasis 20 -- 49 iters
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // nbasis 20 -- 70 iters; asymmetric 
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 58; Loosen coarse, tighten fine
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 56 ... 
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 51 ...  with 24 vecs
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 31 ...  with 24 vecs and 2^4 blocking
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 43 ...  with 16 vecs and 2^4 blocking, sloppier
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 35  ...  with 20 vecs and 2^4 blocking
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 35  ...  with 20 vecs and 2^4 blocking, looser coarse
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 64  ...  with 20 vecs, Christoph setup, and 2^4 blocking, looser coarse
+  ShiftedPVdagM_t ShiftedPVdagM(0.01,Ddwf,Dpv); // 
+
+
+  // Run power method on HOA??
+  PowerMethod<LatticeFermion>       PM;
+  //  PM(PVdagM,src);
+  //  PM(MdagPV,src);
+ 
+  // Warning: This routine calls PVdagM.Op, not PVdagM.HermOp
+  typedef Aggregation<vSpinColourVector,vTComplex,nbasis> Subspace;
+  Subspace V(Coarse5d,FGrid,cb);
+  Subspace U(Coarse5d,FGrid,cb);
+
+  // Breeds right singular vectors with call to HermOp (V)
+  V.CreateSubspace(RNG5,PVdagM,nbasis);
+
+  // Breeds left singular vectors with call to HermOp (U)
+  //  U.CreateSubspaceChebyshev(RNG5,MdagPV,
+  U.CreateSubspace(RNG5,PVdagM,nbasis);
+  
+  typedef Aggregation<vSpinColourVector,vTComplex,2*nbasis> CombinedSubspace;
+  CombinedSubspace CombinedUV(Coarse5d,FGrid,cb);
+  for(int b=0;b<nbasis;b++){
+    CombinedUV.subspace[b]        = V.subspace[b];
+    CombinedUV.subspace[b+nbasis] = U.subspace[b];
+  }
+
+  int bl, br;
+  std::cout <<" <V| PVdagM| V> " <<std::endl;
+  for(bl=0;bl<nbasis;bl++){
+  for(br=0;br<nbasis;br++){
+    PVdagM.Op(V.subspace[br],src);
+    std::cout <<bl<<" "<<br<<"\t"<<innerProduct(V.subspace[bl],src)<<std::endl;
+  }}
+  std::cout <<" <V| PVdagM| U> " <<std::endl;
+  for(bl=0;bl<nbasis;bl++){
+  for(br=0;br<nbasis;br++){
+    PVdagM.Op(U.subspace[br],src);
+    std::cout <<bl<<" "<<br<<"\t"<<innerProduct(V.subspace[bl],src)<<std::endl;
+  }}
+  std::cout <<" <U| PVdagM| V> " <<std::endl;
+  for(bl=0;bl<nbasis;bl++){
+  for(br=0;br<nbasis;br++){
+    PVdagM.Op(V.subspace[br],src);
+    std::cout <<bl<<" "<<br<<"\t"<<innerProduct(U.subspace[bl],src)<<std::endl;
+  }}
+  std::cout <<" <U| PVdagM| U> " <<std::endl;
+  for(bl=0;bl<nbasis;bl++){
+  for(br=0;br<nbasis;br++){
+    PVdagM.Op(U.subspace[br],src);
+    std::cout <<bl<<" "<<br<<"\t"<<innerProduct(U.subspace[bl],src)<<std::endl;
+  }}
+
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,nbasis> LittleDiracOperatorV;
+  typedef LittleDiracOperatorV::CoarseVector CoarseVectorV;
+  
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,2*nbasis> LittleDiracOperator;
+  typedef LittleDiracOperator::CoarseVector CoarseVector;
+
+  V.Orthogonalise();
+  for(int b =0 ; b<nbasis;b++){
+    CoarseVectorV c_src (Coarse5d);
+    V.ProjectToSubspace  (c_src,U.subspace[b]);
+    V.PromoteFromSubspace(c_src,src);
+    std::cout << " Completeness of U in V ["<< b<<"] "<< std::sqrt(norm2(src)/norm2(U.subspace[b]))<<std::endl;
+  }
+  
+  CoarseVector c_src (Coarse5d);
+  CoarseVector c_res (Coarse5d);
+  CoarseVector c_proj(Coarse5d);
+  LittleDiracOperator LittleDiracOpPV(geom,FGrid,Coarse5d);
+  LittleDiracOpPV.CoarsenOperator(PVdagM,CombinedUV,CombinedUV);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"Testing coarsened operator "<<std::endl;
+  
+  Complex one(1.0);
+  c_src = one;  // 1 in every element for vector 1.
+
+  blockPromote(c_src,err,CombinedUV.subspace);
+
+  LatticeFermion prom(FGrid);
+  prom=Zero();
+  for(int b=0;b<nbasis*2;b++){
+    prom=prom+CombinedUV.subspace[b];
+  }
+
+  std::cout<<GridLogMessage<<"c_src "<<norm2(c_src)<<std::endl;
+  std::cout<<GridLogMessage<<"prom  "<<norm2(prom)<<std::endl;
+
+  PVdagM.Op(prom,tmp);
+  blockProject(c_proj,tmp,CombinedUV.subspace);
+  std::cout<<GridLogMessage<<" Called Big Dirac Op "<<norm2(tmp)<<std::endl;
+
+  LittleDiracOpPV.M(c_src,c_res);
+  std::cout<<GridLogMessage<<" Called Little Dirac Op c_src "<< norm2(c_src) << "  c_res "<< norm2(c_res) <<std::endl;
+
+  std::cout<<GridLogMessage<<"Little dop : "<<norm2(c_res)<<std::endl;
+
+  std::cout<<GridLogMessage<<"Big dop in subspace : "<<norm2(c_proj)<<std::endl;
+
+  c_proj = c_proj - c_res;
+  std::cout<<GridLogMessage<<" ldop error: "<<norm2(c_proj)<<std::endl;
+
+
+  /**********
+   * Some solvers
+   **********
+   */
+
+  ///////////////////////////////////////
+  // Coarse grid solver test
+  ///////////////////////////////////////
+
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Coarse Grid Solve -- Level 3 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<CoarseVector> simple;
+  NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOpPV);
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-4, 100, LinOpCoarse,simple,10,10); 
+  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-2, 10, LinOpCoarse,simple,20,20); 
+  L2PGCR.Level(3);
+  c_res=Zero();
+  L2PGCR(c_src,c_res);
+
+  ////////////////////////////////////////
+  // Fine grid smoother
+  ////////////////////////////////////////
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Fine Grid Smoother -- Level 2 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<LatticeFermionD> simple_fine;
+  //  NonHermitianLinearOperator<PVdagM_t,LatticeFermionD> LinOpSmooth(PVdagM);
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> SmootherGCR(0.01,1,ShiftedPVdagM,simple_fine,16,16);
+  SmootherGCR.Level(2);
+  
+  LatticeFermionD f_src(FGrid);
+  LatticeFermionD f_res(FGrid);
+
+  f_src = one;  // 1 in every element for vector 1.
+  f_res=Zero();
+  SmootherGCR(f_src,f_res);
+
+  typedef MGPreconditionerSVD<vSpinColourVector,  vTComplex,nbasis*2> TwoLevelMG;
+
+  TwoLevelMG TwoLevelPrecon(CombinedUV,CombinedUV,
+			    PVdagM,
+			    simple_fine,
+			    SmootherGCR,
+			    LinOpCoarse,
+			    L2PGCR);
+  
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,1000,PVdagM,TwoLevelPrecon,20,20);
+  L1PGCR.Level(1);
+
+  f_res=Zero();
+  L1PGCR(f_src,f_res);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage << "Done "<< std::endl;
+
+  Grid_finalize();
+  return 0;
+}

tests/debug/Test_general_coarse_pvdagm_svd_uv.cc

@@ -0,0 +1,479 @@
+/*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_padded_cell.cc
+
+    Copyright (C) 2023
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+#include <Grid/lattice/PaddedCell.h>
+#include <Grid/stencil/GeneralLocalStencil.h>
+
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidual.h>
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
+#include <Grid/algorithms/iterative/BiCGSTAB.h>
+
+using namespace std;
+using namespace Grid;
+
+template<class Matrix,class Field>
+class PVdagMLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+public:
+  PVdagMLinearOperator(Matrix &Mat,Matrix &PV): _Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    //    std::cout << GridLogMessage<< "Op: PVdag M "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout << GridLogMessage<<"AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _PV.M(in,tmp);
+    _Mat.Mdag(tmp,out);
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){
+    assert(0);
+  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout <<GridLogMessage<< "HermOp: Mdag PV PVdag M"<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+    //    std::cout << "HermOp done "<<norm2(out)<<std::endl;
+  }
+};
+template<class Matrix,class Field>
+class MdagPVLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+public:
+  MdagPVLinearOperator(Matrix &Mat,Matrix &PV): _Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    Field tmp(in.Grid());
+    //    std::cout <<GridLogMessage<< "Op: PVdag M "<<std::endl;
+    _PV.M(in,tmp);
+    _Mat.Mdag(tmp,out);
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout <<GridLogMessage<< "AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){
+    assert(0);
+  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout << GridLogMessage<<"HermOp: PVdag M Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+    //    std::cout << "HermOp done "<<norm2(out)<<std::endl;
+  }
+};
+template<class Matrix,class Field>
+class ShiftedPVdagMLinearOperator : public LinearOperatorBase<Field> {
+  Matrix &_Mat;
+  Matrix &_PV;
+  RealD shift;
+public:
+  ShiftedPVdagMLinearOperator(RealD _shift,Matrix &Mat,Matrix &PV): shift(_shift),_Mat(Mat),_PV(PV){};
+
+  void OpDiag (const Field &in, Field &out) {    assert(0);  }
+  void OpDir  (const Field &in, Field &out,int dir,int disp) {    assert(0);  }
+  void OpDirAll  (const Field &in, std::vector<Field> &out){    assert(0);  };
+  void Op     (const Field &in, Field &out){
+    //    std::cout << "Op: PVdag M "<<std::endl;
+    Field tmp(in.Grid());
+    _Mat.M(in,tmp);
+    _PV.Mdag(tmp,out);
+    out = out + shift * in;
+  }
+  void AdjOp     (const Field &in, Field &out){
+    //    std::cout << "AdjOp: Mdag PV "<<std::endl;
+    Field tmp(in.Grid());
+    _PV.M(tmp,out);
+    _Mat.Mdag(in,tmp);
+    out = out + shift * in;
+  }
+  void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){    assert(0);  }
+  void HermOp(const Field &in, Field &out){
+    //    std::cout << "HermOp: Mdag PV PVdag M"<<std::endl;
+    Field tmp(in.Grid());
+    Op(in,tmp);
+    AdjOp(tmp,out);
+  }
+};
+template<class Fobj,class CComplex,int nbasis>
+class MGPreconditionerSVD : public LinearFunction< Lattice<Fobj> > {
+public:
+  using LinearFunction<Lattice<Fobj> >::operator();
+
+  typedef Aggregation<Fobj,CComplex,nbasis> Aggregates;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::FineField    FineField;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseVector CoarseVector;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseMatrix CoarseMatrix;
+  typedef LinearOperatorBase<FineField>                            FineOperator;
+  typedef LinearFunction    <FineField>                            FineSmoother;
+  typedef LinearOperatorBase<CoarseVector>                         CoarseOperator;
+  typedef LinearFunction    <CoarseVector>                         CoarseSolver;
+  ///////////////////////////////
+  // SVD is M = U S Vdag
+  //
+  // Define a subset of Vc and Uc in Complex_f,c  matrix
+  // - these are the coarsening, non-square matrices
+  //
+  // Solve a coarse approx to
+  //
+  //      M psi = eta
+  //
+  //  via
+  //
+  //  Uc^dag U S Vdag Vc Vc^dag psi = Uc^dag eta
+  //
+  //  M_coarse Vc^dag psi = M_coarse psi_c = eta_c
+  //  
+  ///////////////////////////////
+  Aggregates     & _U;
+  Aggregates     & _V;
+  FineOperator   & _FineOperator;
+  FineSmoother   & _PreSmoother;
+  FineSmoother   & _PostSmoother;
+  CoarseOperator & _CoarseOperator;
+  CoarseSolver   & _CoarseSolve;
+
+  int    level;  void Level(int lv) {level = lv; };
+
+  MGPreconditionerSVD(Aggregates &U,
+		      Aggregates &V,
+		      FineOperator &Fine,
+		      FineSmoother &PreSmoother,
+		      FineSmoother &PostSmoother,
+		      CoarseOperator &CoarseOperator_,
+		      CoarseSolver &CoarseSolve_)
+    : _U(U),
+      _V(V),
+      _FineOperator(Fine),
+      _PreSmoother(PreSmoother),
+      _PostSmoother(PostSmoother),
+      _CoarseOperator(CoarseOperator_),
+      _CoarseSolve(CoarseSolve_),
+      level(1)  {  }
+
+  virtual void operator()(const FineField &in, FineField & out) 
+  {
+    GridBase *CoarseGrid = _U.CoarseGrid;
+    //    auto CoarseGrid = _CoarseOperator.Grid();
+    CoarseVector Csrc(CoarseGrid);
+    CoarseVector Csol(CoarseGrid);
+    FineField vec1(in.Grid());
+    FineField vec2(in.Grid());
+
+    std::cout<<GridLogMessage << "Calling PreSmoother " <<std::endl;
+
+    //    std::cout<<GridLogMessage << "Calling PreSmoother input residual "<<norm2(in) <<std::endl;
+    double t;
+    // Fine Smoother
+    //    out = in;
+    out = Zero();
+    t=-usecond();
+    _PreSmoother(in,out);
+    t+=usecond();
+
+    std::cout<<GridLogMessage << "PreSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Update the residual
+    _FineOperator.Op(out,vec1);  sub(vec1, in ,vec1);   
+    //    std::cout<<GridLogMessage <<"Residual-1 now " <<norm2(vec1)<<std::endl;
+
+    //  Uc^dag U S Vdag Vc Vc^dag psi = Uc^dag eta
+    // Fine to Coarse 
+    t=-usecond();
+    _U.ProjectToSubspace  (Csrc,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Project to coarse took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse correction
+    t=-usecond();
+    Csol = Zero();
+    _CoarseSolve(Csrc,Csol);
+    //Csol=Zero();
+    t+=usecond();
+    std::cout<<GridLogMessage << "Coarse solve took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse to Fine
+    t=-usecond();  
+    //    _CoarseOperator.PromoteFromSubspace(_Aggregates,Csol,vec1);
+    _V.PromoteFromSubspace(Csol,vec1); 
+    add(out,out,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Promote to this level took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Residual
+    _FineOperator.Op(out,vec1);  sub(vec1 ,in , vec1);  
+    //    std::cout<<GridLogMessage <<"Residual-2 now " <<norm2(vec1)<<std::endl;
+
+    // Fine Smoother
+    t=-usecond();
+    //    vec2=vec1;
+    vec2=Zero();
+    _PostSmoother(vec1,vec2);
+    t+=usecond();
+    std::cout<<GridLogMessage << "PostSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    add( out,out,vec2);
+    std::cout<<GridLogMessage << "Done " <<std::endl;
+  }
+};
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=16;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+
+  GridCartesian         * FGrid   = SpaceTimeGrid::makeFiveDimGrid(Ls,UGrid);
+  GridRedBlackCartesian * FrbGrid = SpaceTimeGrid::makeFiveDimRedBlackGrid(Ls,UGrid);
+
+  // Construct a coarsened grid
+  Coordinate clatt = GridDefaultLatt();
+  for(int d=0;d<clatt.size();d++){
+    clatt[d] = clatt[d]/2;
+    //    clatt[d] = clatt[d]/4;
+  }
+  GridCartesian *Coarse4d =  SpaceTimeGrid::makeFourDimGrid(clatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());;
+  GridCartesian *Coarse5d =  SpaceTimeGrid::makeFiveDimGrid(1,Coarse4d);
+
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> seeds5({5,6,7,8});
+  std::vector<int> cseeds({5,6,7,8});
+  GridParallelRNG          RNG5(FGrid);   RNG5.SeedFixedIntegers(seeds5);
+  GridParallelRNG          RNG4(UGrid);   RNG4.SeedFixedIntegers(seeds4);
+  GridParallelRNG          CRNG(Coarse5d);CRNG.SeedFixedIntegers(cseeds);
+
+  LatticeFermion    src(FGrid); random(RNG5,src);
+  LatticeFermion result(FGrid); result=Zero();
+  LatticeFermion    ref(FGrid); ref=Zero();
+  LatticeFermion    tmp(FGrid);
+  LatticeFermion    err(FGrid);
+  LatticeGaugeField Umu(UGrid);
+
+  FieldMetaData header;
+  std::string file("ckpoint_lat.4000");
+  NerscIO::readConfiguration(Umu,header,file);
+  
+  RealD mass=0.01;
+  RealD M5=1.8;
+
+  DomainWallFermionD Ddwf(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,mass,M5);
+  DomainWallFermionD Dpv(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,1.0,M5);
+
+  const int nbasis = 60;
+  const int cb = 0 ;
+
+  NextToNearestStencilGeometry5D geom(Coarse5d);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+
+  typedef PVdagMLinearOperator<DomainWallFermionD,LatticeFermionD> PVdagM_t;
+  typedef MdagPVLinearOperator<DomainWallFermionD,LatticeFermionD> MdagPV_t;
+  typedef ShiftedPVdagMLinearOperator<DomainWallFermionD,LatticeFermionD> ShiftedPVdagM_t;
+  PVdagM_t PVdagM(Ddwf,Dpv);
+  MdagPV_t MdagPV(Ddwf,Dpv);
+  //  ShiftedPVdagM_t ShiftedPVdagM(2.0,Ddwf,Dpv); // 355
+  //  ShiftedPVdagM_t ShiftedPVdagM(1.0,Ddwf,Dpv); // 246
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.5,Ddwf,Dpv); // 183
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 145
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 134
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 127 -- NULL space via inverse iteration
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 57 -- NULL space via inverse iteration; 3 iterations
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 57 , tighter inversion
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // nbasis 20 -- 49 iters
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // nbasis 20 -- 70 iters; asymmetric 
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.25,Ddwf,Dpv); // 58; Loosen coarse, tighten fine
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 56 ... 
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 51 ...  with 24 vecs
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 31 ...  with 24 vecs and 2^4 blocking
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 43 ...  with 16 vecs and 2^4 blocking, sloppier
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 35  ...  with 20 vecs and 2^4 blocking
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 35  ...  with 20 vecs and 2^4 blocking, looser coarse
+  //  ShiftedPVdagM_t ShiftedPVdagM(0.1,Ddwf,Dpv); // 64  ...  with 20 vecs, Christoph setup, and 2^4 blocking, looser coarse
+  ShiftedPVdagM_t ShiftedPVdagM(0.01,Ddwf,Dpv); // 
+
+
+  // Run power method on HOA??
+  PowerMethod<LatticeFermion>       PM;
+  PM(PVdagM,src);
+  PM(MdagPV,src);
+
+ 
+  // Warning: This routine calls PVdagM.Op, not PVdagM.HermOp
+  typedef Aggregation<vSpinColourVector,vTComplex,nbasis> Subspace;
+  Subspace V(Coarse5d,FGrid,cb);
+  //  Subspace U(Coarse5d,FGrid,cb);
+
+  // Breeds right singular vectors with call to HermOp
+  V.CreateSubspaceChebyshev(RNG5,PVdagM,
+			    nbasis,
+			    4000.0,0.003,
+			    300);
+
+  // Breeds left singular vectors with call to HermOp
+  //  U.CreateSubspaceChebyshev(RNG5,MdagPV,
+  //			    nbasis,
+  //			    4000.0,0.003,
+  //			    300);
+  //  U.subspace=V.subspace;
+  
+  //  typedef Aggregation<vSpinColourVector,vTComplex,2*nbasis> CombinedSubspace;
+  //  CombinedSubspace CombinedUV(Coarse5d,FGrid,cb);
+  //  for(int b=0;b<nbasis;b++){
+  //    CombinedUV.subspace[b]        = V.subspace[b];
+  //    CombinedUV.subspace[b+nbasis] = U.subspace[b];
+  //  }
+  
+  
+  //  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,2*nbasis> LittleDiracOperator;
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,nbasis> LittleDiracOperator;
+  typedef LittleDiracOperator::CoarseVector CoarseVector;
+  LittleDiracOperator LittleDiracOpPV(geom,FGrid,Coarse5d);
+  LittleDiracOpPV.CoarsenOperator(PVdagM,V,V);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"Testing coarsened operator "<<std::endl;
+  
+  CoarseVector c_src (Coarse5d);
+  CoarseVector c_res (Coarse5d);
+  CoarseVector c_proj(Coarse5d);
+
+
+  Complex one(1.0);
+  c_src = one;  // 1 in every element for vector 1.
+
+  //  blockPromote(c_src,err,CoarseToFine.subspace);
+
+  LatticeFermion prom(FGrid);
+  prom=Zero();
+  for(int b=0;b<nbasis;b++){
+    prom=prom+V.subspace[b];
+  }
+
+  std::cout<<GridLogMessage<<"c_src "<<norm2(c_src)<<std::endl;
+  std::cout<<GridLogMessage<<"prom  "<<norm2(prom)<<std::endl;
+
+  PVdagM.Op(prom,tmp);
+  blockProject(c_proj,tmp,V.subspace);
+  std::cout<<GridLogMessage<<" Called Big Dirac Op "<<norm2(tmp)<<std::endl;
+
+  LittleDiracOpPV.M(c_src,c_res);
+  std::cout<<GridLogMessage<<" Called Little Dirac Op c_src "<< norm2(c_src) << "  c_res "<< norm2(c_res) <<std::endl;
+
+  std::cout<<GridLogMessage<<"Little dop : "<<norm2(c_res)<<std::endl;
+
+  std::cout<<GridLogMessage<<"Big dop in subspace : "<<norm2(c_proj)<<std::endl;
+
+  c_proj = c_proj - c_res;
+  std::cout<<GridLogMessage<<" ldop error: "<<norm2(c_proj)<<std::endl;
+
+
+  /**********
+   * Some solvers
+   **********
+   */
+
+  ///////////////////////////////////////
+  // Coarse grid solver test
+  ///////////////////////////////////////
+
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Coarse Grid Solve -- Level 3 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<CoarseVector> simple;
+  NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOpPV);
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-4, 100, LinOpCoarse,simple,10,10); 
+  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L3PGCR(1.0e-4, 10, LinOpCoarse,simple,20,20); 
+  L3PGCR.Level(3);
+  c_res=Zero();
+  L3PGCR(c_src,c_res);
+
+  ////////////////////////////////////////
+  // Fine grid smoother
+  ////////////////////////////////////////
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Fine Grid Smoother -- Level 2 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<LatticeFermionD> simple_fine;
+  //  NonHermitianLinearOperator<PVdagM_t,LatticeFermionD> LinOpSmooth(PVdagM);
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> SmootherGCR(0.01,1,ShiftedPVdagM,simple_fine,16,16);
+  SmootherGCR.Level(2);
+  
+  LatticeFermionD f_src(FGrid);
+  LatticeFermionD f_res(FGrid);
+
+  f_src = one;  // 1 in every element for vector 1.
+  f_res=Zero();
+  SmootherGCR(f_src,f_res);
+
+  //  typedef MGPreconditionerSVD<vSpinColourVector,  vTComplex,nbasis*2> TwoLevelMG;
+  typedef MGPreconditionerSVD<vSpinColourVector,  vTComplex,nbasis> TwoLevelMG;
+
+  //  TwoLevelMG TwoLevelPrecon(CombinedUV,CombinedUV,
+  TwoLevelMG TwoLevelPrecon(V,V,
+			    PVdagM,
+			    simple_fine,
+			    SmootherGCR,
+			    LinOpCoarse,
+			    L3PGCR);
+  
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,1000,PVdagM,TwoLevelPrecon,16,16);
+  L1PGCR.Level(1);
+
+  f_res=Zero();
+  L1PGCR(f_src,f_res);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage << "Done "<< std::endl;
+
+  Grid_finalize();
+  return 0;
+}

tests/debug/Test_general_coarse_wilson.cc

@@ -0,0 +1,333 @@
+/*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_padded_cell.cc
+
+    Copyright (C) 2023
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+#include <Grid/lattice/PaddedCell.h>
+#include <Grid/stencil/GeneralLocalStencil.h>
+
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidual.h>
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
+#include <Grid/algorithms/iterative/BiCGSTAB.h>
+
+using namespace std;
+using namespace Grid;
+
+template<class Fobj,class CComplex,int nbasis>
+class MGPreconditioner : public LinearFunction< Lattice<Fobj> > {
+public:
+  using LinearFunction<Lattice<Fobj> >::operator();
+
+  typedef Aggregation<Fobj,CComplex,nbasis> Aggregates;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::FineField    FineField;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseVector CoarseVector;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseMatrix CoarseMatrix;
+  typedef LinearOperatorBase<FineField>                            FineOperator;
+  typedef LinearFunction    <FineField>                            FineSmoother;
+  typedef LinearOperatorBase<CoarseVector>                         CoarseOperator;
+  typedef LinearFunction    <CoarseVector>                         CoarseSolver;
+  Aggregates     & _Aggregates;
+  FineOperator   & _FineOperator;
+  FineSmoother   & _PreSmoother;
+  FineSmoother   & _PostSmoother;
+  CoarseOperator & _CoarseOperator;
+  CoarseSolver   & _CoarseSolve;
+
+  int    level;  void Level(int lv) {level = lv; };
+
+  MGPreconditioner(Aggregates &Agg,
+		   FineOperator &Fine,
+		   FineSmoother &PreSmoother,
+		   FineSmoother &PostSmoother,
+		   CoarseOperator &CoarseOperator_,
+		   CoarseSolver &CoarseSolve_)
+    : _Aggregates(Agg),
+      _FineOperator(Fine),
+      _PreSmoother(PreSmoother),
+      _PostSmoother(PostSmoother),
+      _CoarseOperator(CoarseOperator_),
+      _CoarseSolve(CoarseSolve_),
+      level(1)  {  }
+
+  virtual void operator()(const FineField &in, FineField & out) 
+  {
+    GridBase *CoarseGrid = _Aggregates.CoarseGrid;
+    //    auto CoarseGrid = _CoarseOperator.Grid();
+    CoarseVector Csrc(CoarseGrid);
+    CoarseVector Csol(CoarseGrid);
+    FineField vec1(in.Grid());
+    FineField vec2(in.Grid());
+
+    std::cout<<GridLogMessage << "Calling PreSmoother " <<std::endl;
+
+    //    std::cout<<GridLogMessage << "Calling PreSmoother input residual "<<norm2(in) <<std::endl;
+    double t;
+    // Fine Smoother
+    //    out = in;
+    out = Zero();
+    t=-usecond();
+    _PreSmoother(in,out);
+    t+=usecond();
+
+    std::cout<<GridLogMessage << "PreSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Update the residual
+    _FineOperator.Op(out,vec1);  sub(vec1, in ,vec1);   
+    //    std::cout<<GridLogMessage <<"Residual-1 now " <<norm2(vec1)<<std::endl;
+
+    // Fine to Coarse 
+    t=-usecond();
+    _Aggregates.ProjectToSubspace  (Csrc,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Project to coarse took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse correction
+    t=-usecond();
+    Csol = Zero();
+    _CoarseSolve(Csrc,Csol);
+    //Csol=Zero();
+    t+=usecond();
+    std::cout<<GridLogMessage << "Coarse solve took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse to Fine
+    t=-usecond();  
+    //    _CoarseOperator.PromoteFromSubspace(_Aggregates,Csol,vec1);
+    _Aggregates.PromoteFromSubspace(Csol,vec1); 
+    add(out,out,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Promote to this level took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Residual
+    _FineOperator.Op(out,vec1);  sub(vec1 ,in , vec1);  
+    //    std::cout<<GridLogMessage <<"Residual-2 now " <<norm2(vec1)<<std::endl;
+
+    // Fine Smoother
+    t=-usecond();
+    //    vec2=vec1;
+    vec2=Zero();
+    _PostSmoother(vec1,vec2);
+    t+=usecond();
+    std::cout<<GridLogMessage << "PostSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    add( out,out,vec2);
+    std::cout<<GridLogMessage << "Done " <<std::endl;
+  }
+};
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=16;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+
+  GridCartesian         * FGrid   = UGrid;
+  GridRedBlackCartesian * FrbGrid = UrbGrid;
+
+  // Construct a coarsened grid
+  Coordinate clatt = GridDefaultLatt();
+  for(int d=0;d<clatt.size();d++){
+    clatt[d] = clatt[d]/2;
+    //clatt[d] = clatt[d]/4;
+  }
+  GridCartesian *Coarse4d =  SpaceTimeGrid::makeFourDimGrid(clatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());;
+
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> cseeds({5,6,7,8});
+  GridParallelRNG          RNG4(UGrid);   RNG4.SeedFixedIntegers(seeds4);
+  GridParallelRNG          CRNG(Coarse4d);CRNG.SeedFixedIntegers(cseeds);
+
+  Complex one(1.0);
+
+  LatticeFermion    src(FGrid); src=one;
+  LatticeFermion result(FGrid); result=Zero();
+  LatticeFermion    ref(FGrid); ref=Zero();
+  LatticeFermion    tmp(FGrid);
+  LatticeFermion    err(FGrid);
+  LatticeFermion    precsrc(FGrid);
+  LatticeGaugeField Umu(UGrid);
+
+  FieldMetaData header;
+  std::string file("ckpoint_lat");
+  NerscIO::readConfiguration(Umu,header,file);
+
+  RealD csw =0.0;
+  RealD mass=-0.92;
+
+  WilsonCloverFermionD Dw(Umu,*UGrid,*UrbGrid,mass,csw,csw);
+
+  const int nbasis = 20;
+  const int cb = 0 ;
+  LatticeFermion prom(FGrid);
+
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,2*nbasis> LittleDiracOperator;
+  typedef LittleDiracOperator::CoarseVector CoarseVector;
+
+  NearestStencilGeometry4D geom(Coarse4d);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+ 
+  // Warning: This routine calls Linop.Op, not LinOpo.HermOp
+  typedef Aggregation<vSpinColourVector,vTComplex,nbasis> Subspace;
+  Subspace Aggregates(Coarse4d,FGrid,cb);
+
+  NonHermitianLinearOperator<WilsonCloverFermionD,LatticeFermion> LinOpDw(Dw);
+  ShiftedNonHermitianLinearOperator<WilsonCloverFermionD,LatticeFermion> ShiftedLinOpDw(Dw,0.01);
+
+  Aggregates.CreateSubspaceGCR(RNG4,
+			       LinOpDw,
+			       nbasis);
+  
+  typedef Aggregation<vSpinColourVector,vTComplex,2*nbasis> CombinedSubspace;
+  CombinedSubspace CombinedUV(Coarse4d,UGrid,cb);
+  for(int b=0;b<nbasis;b++){
+    Gamma G5(Gamma::Algebra::Gamma5);
+    CombinedUV.subspace[b]        = Aggregates.subspace[b];
+    CombinedUV.subspace[b+nbasis] = G5*Aggregates.subspace[b];
+  }
+
+  LittleDiracOperator LittleDiracOp(geom,FGrid,Coarse4d);
+  LittleDiracOp.CoarsenOperator(LinOpDw,CombinedUV);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"Testing coarsened operator "<<std::endl;
+  
+  CoarseVector c_src (Coarse4d);
+  CoarseVector c_res (Coarse4d);
+  CoarseVector c_proj(Coarse4d);
+
+  std::vector<LatticeFermion> subspace(2*nbasis,FGrid);
+  subspace=CombinedUV.subspace;
+
+  c_src = one;  // 1 in every element for vector 1.
+  blockPromote(c_src,err,subspace);
+
+  prom=Zero();
+  for(int b=0;b<2*nbasis;b++){
+    prom=prom+subspace[b];
+  }
+  err=err-prom; 
+  std::cout<<GridLogMessage<<"Promoted back from subspace: err "<<norm2(err)<<std::endl;
+  std::cout<<GridLogMessage<<"c_src "<<norm2(c_src)<<std::endl;
+  std::cout<<GridLogMessage<<"prom  "<<norm2(prom)<<std::endl;
+
+  LinOpDw.Op(prom,tmp);
+  blockProject(c_proj,tmp,subspace);
+  std::cout<<GridLogMessage<<" Called Big Dirac Op "<<norm2(tmp)<<std::endl;
+
+  LittleDiracOp.M(c_src,c_res);
+  std::cout<<GridLogMessage<<" Called Little Dirac Op c_src "<< norm2(c_src) << "  c_res "<< norm2(c_res) <<std::endl;
+
+  std::cout<<GridLogMessage<<"Little dop : "<<norm2(c_res)<<std::endl;
+  //  std::cout<<GridLogMessage<<" Little "<< c_res<<std::endl;
+
+  std::cout<<GridLogMessage<<"Big dop in subspace : "<<norm2(c_proj)<<std::endl;
+  //  std::cout<<GridLogMessage<<" Big "<< c_proj<<std::endl;
+  c_proj = c_proj - c_res;
+  std::cout<<GridLogMessage<<" ldop error: "<<norm2(c_proj)<<std::endl;
+  //  std::cout<<GridLogMessage<<" error "<< c_proj<<std::endl;
+
+
+  /**********
+   * Some solvers
+   **********
+   */
+
+  // CG
+  {
+    MdagMLinearOperator<WilsonFermionD,LatticeFermion> HermOp(Dw);
+    ConjugateGradient<LatticeFermion> CG(1.0e-8,10000);
+    Dw.Mdag(src,precsrc);
+    CG(HermOp,precsrc,result);
+    result=Zero();
+  }
+ 
+  ///////////////////////////////////////
+  // Coarse grid solver test
+  ///////////////////////////////////////
+
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Coarse Grid Solve -- Level 3 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<CoarseVector> simple;
+  NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOp);
+  ShiftedNonHermitianLinearOperator<LittleDiracOperator,CoarseVector> ShiftedLinOpCoarse(LittleDiracOp,0.001);
+  //  ShiftedNonHermitianLinearOperator<LittleDiracOperator,CoarseVector> ShiftedLinOpCoarse(LittleDiracOp,0.01);
+  //  ShiftedNonHermitianLinearOperator<LittleDiracOperator,CoarseVector> ShiftedLinOpCoarse(LinOpCoarse,0.001);
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-4, 100, LinOpCoarse,simple,10,10); 
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-1, 100, LinOpCoarse,simple,30,30); 
+  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(2.0e-1, 50, ShiftedLinOpCoarse,simple,50,50); 
+  L2PGCR.Level(3);
+  c_res=Zero();
+  L2PGCR(c_src,c_res);
+
+  ////////////////////////////////////////
+  // Fine grid smoother
+  ////////////////////////////////////////
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Fine Grid Smoother -- Level 2 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<LatticeFermionD> simple_fine;
+
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> SmootherGCR(0.1,1,ShiftedLinOpDw,simple_fine,4,4);
+  SmootherGCR.Level(2);
+  
+  LatticeFermionD f_src(FGrid);
+  LatticeFermionD f_res(FGrid);
+
+  f_src = one;  // 1 in every element for vector 1.
+  f_res=Zero();
+  SmootherGCR(f_src,f_res);
+
+  typedef MGPreconditioner<vSpinColourVector,  vTComplex,2*nbasis> TwoLevelMG;
+
+  TwoLevelMG TwoLevelPrecon(CombinedUV,
+			    LinOpDw,
+			    simple_fine,
+			    SmootherGCR,
+			    LinOpCoarse,
+			    L2PGCR);
+  
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,1000,LinOpDw,TwoLevelPrecon,16,16);
+  L1PGCR.Level(1);
+
+  f_res=Zero();
+  L1PGCR(f_src,f_res);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage << "Done "<< std::endl;
+
+  Grid_finalize();
+  return 0;
+}

tests/debug/Test_general_coarse_wilson_nog5.cc

@@ -0,0 +1,326 @@
+/*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_padded_cell.cc
+
+    Copyright (C) 2023
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+#include <Grid/lattice/PaddedCell.h>
+#include <Grid/stencil/GeneralLocalStencil.h>
+
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidual.h>
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
+#include <Grid/algorithms/iterative/BiCGSTAB.h>
+
+using namespace std;
+using namespace Grid;
+
+template<class Fobj,class CComplex,int nbasis>
+class MGPreconditioner : public LinearFunction< Lattice<Fobj> > {
+public:
+  using LinearFunction<Lattice<Fobj> >::operator();
+
+  typedef Aggregation<Fobj,CComplex,nbasis> Aggregates;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::FineField    FineField;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseVector CoarseVector;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseMatrix CoarseMatrix;
+  typedef LinearOperatorBase<FineField>                            FineOperator;
+  typedef LinearFunction    <FineField>                            FineSmoother;
+  typedef LinearOperatorBase<CoarseVector>                         CoarseOperator;
+  typedef LinearFunction    <CoarseVector>                         CoarseSolver;
+  Aggregates     & _Aggregates;
+  FineOperator   & _FineOperator;
+  FineSmoother   & _PreSmoother;
+  FineSmoother   & _PostSmoother;
+  CoarseOperator & _CoarseOperator;
+  CoarseSolver   & _CoarseSolve;
+
+  int    level;  void Level(int lv) {level = lv; };
+
+  MGPreconditioner(Aggregates &Agg,
+		   FineOperator &Fine,
+		   FineSmoother &PreSmoother,
+		   FineSmoother &PostSmoother,
+		   CoarseOperator &CoarseOperator_,
+		   CoarseSolver &CoarseSolve_)
+    : _Aggregates(Agg),
+      _FineOperator(Fine),
+      _PreSmoother(PreSmoother),
+      _PostSmoother(PostSmoother),
+      _CoarseOperator(CoarseOperator_),
+      _CoarseSolve(CoarseSolve_),
+      level(1)  {  }
+
+  virtual void operator()(const FineField &in, FineField & out) 
+  {
+    GridBase *CoarseGrid = _Aggregates.CoarseGrid;
+    //    auto CoarseGrid = _CoarseOperator.Grid();
+    CoarseVector Csrc(CoarseGrid);
+    CoarseVector Csol(CoarseGrid);
+    FineField vec1(in.Grid());
+    FineField vec2(in.Grid());
+
+    std::cout<<GridLogMessage << "Calling PreSmoother " <<std::endl;
+
+    //    std::cout<<GridLogMessage << "Calling PreSmoother input residual "<<norm2(in) <<std::endl;
+    double t;
+    // Fine Smoother
+    //    out = in;
+    out = Zero();
+    t=-usecond();
+    _PreSmoother(in,out);
+    t+=usecond();
+
+    std::cout<<GridLogMessage << "PreSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Update the residual
+    _FineOperator.Op(out,vec1);  sub(vec1, in ,vec1);   
+    //    std::cout<<GridLogMessage <<"Residual-1 now " <<norm2(vec1)<<std::endl;
+
+    // Fine to Coarse 
+    t=-usecond();
+    _Aggregates.ProjectToSubspace  (Csrc,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Project to coarse took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse correction
+    t=-usecond();
+    Csol = Zero();
+    _CoarseSolve(Csrc,Csol);
+    //Csol=Zero();
+    t+=usecond();
+    std::cout<<GridLogMessage << "Coarse solve took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse to Fine
+    t=-usecond();  
+    //    _CoarseOperator.PromoteFromSubspace(_Aggregates,Csol,vec1);
+    _Aggregates.PromoteFromSubspace(Csol,vec1); 
+    add(out,out,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Promote to this level took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Residual
+    _FineOperator.Op(out,vec1);  sub(vec1 ,in , vec1);  
+    //    std::cout<<GridLogMessage <<"Residual-2 now " <<norm2(vec1)<<std::endl;
+
+    // Fine Smoother
+    t=-usecond();
+    //    vec2=vec1;
+    vec2=Zero();
+    _PostSmoother(vec1,vec2);
+    t+=usecond();
+    std::cout<<GridLogMessage << "PostSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    add( out,out,vec2);
+    std::cout<<GridLogMessage << "Done " <<std::endl;
+  }
+};
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=16;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+
+  GridCartesian         * FGrid   = UGrid;
+  GridRedBlackCartesian * FrbGrid = UrbGrid;
+
+  // Construct a coarsened grid
+  Coordinate clatt = GridDefaultLatt();
+  for(int d=0;d<clatt.size();d++){
+    clatt[d] = clatt[d]/2;
+    //    clatt[d] = clatt[d]/4;
+  }
+  GridCartesian *Coarse4d =  SpaceTimeGrid::makeFourDimGrid(clatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());;
+
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> cseeds({5,6,7,8});
+  GridParallelRNG          RNG4(UGrid);   RNG4.SeedFixedIntegers(seeds4);
+  GridParallelRNG          CRNG(Coarse4d);CRNG.SeedFixedIntegers(cseeds);
+
+  Complex one(1.0);
+
+  LatticeFermion    src(FGrid); src=one;
+  LatticeFermion result(FGrid); result=Zero();
+  LatticeFermion    ref(FGrid); ref=Zero();
+  LatticeFermion    tmp(FGrid);
+  LatticeFermion    err(FGrid);
+  LatticeFermion    precsrc(FGrid);
+  LatticeGaugeField Umu(UGrid);
+
+  FieldMetaData header;
+  std::string file("ckpoint_lat");
+  NerscIO::readConfiguration(Umu,header,file);
+
+  RealD csw =0.0;
+  RealD mass=-0.92;
+
+  WilsonCloverFermionD Dw(Umu,*UGrid,*UrbGrid,mass,csw,csw);
+
+  const int nbasis = 40;
+  const int cb = 0 ;
+  LatticeFermion prom(FGrid);
+
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,nbasis> LittleDiracOperator;
+  typedef LittleDiracOperator::CoarseVector CoarseVector;
+
+  NearestStencilGeometry4D geom(Coarse4d);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+ 
+  // Warning: This routine calls Linop.Op, not LinOpo.HermOp
+  typedef Aggregation<vSpinColourVector,vTComplex,nbasis> Subspace;
+  Subspace Aggregates(Coarse4d,FGrid,cb);
+
+  NonHermitianLinearOperator<WilsonCloverFermionD,LatticeFermion> LinOpDw(Dw);
+  ShiftedNonHermitianLinearOperator<WilsonCloverFermionD,LatticeFermion> ShiftedLinOpDw(Dw,0.01);
+
+  Aggregates.CreateSubspaceGCR(RNG4,
+			       LinOpDw,
+			       nbasis);
+  
+
+  LittleDiracOperator LittleDiracOp(geom,FGrid,Coarse4d);
+  LittleDiracOp.CoarsenOperator(LinOpDw,Aggregates);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"Testing coarsened operator "<<std::endl;
+  
+  CoarseVector c_src (Coarse4d);
+  CoarseVector c_res (Coarse4d);
+  CoarseVector c_proj(Coarse4d);
+
+  std::vector<LatticeFermion> subspace(nbasis,FGrid);
+  subspace=Aggregates.subspace;
+
+  c_src = one;  // 1 in every element for vector 1.
+  blockPromote(c_src,err,subspace);
+
+  prom=Zero();
+  for(int b=0;b<nbasis;b++){
+    prom=prom+subspace[b];
+  }
+  err=err-prom; 
+  std::cout<<GridLogMessage<<"Promoted back from subspace: err "<<norm2(err)<<std::endl;
+  std::cout<<GridLogMessage<<"c_src "<<norm2(c_src)<<std::endl;
+  std::cout<<GridLogMessage<<"prom  "<<norm2(prom)<<std::endl;
+
+  LinOpDw.Op(prom,tmp);
+  blockProject(c_proj,tmp,subspace);
+  std::cout<<GridLogMessage<<" Called Big Dirac Op "<<norm2(tmp)<<std::endl;
+
+  LittleDiracOp.M(c_src,c_res);
+  std::cout<<GridLogMessage<<" Called Little Dirac Op c_src "<< norm2(c_src) << "  c_res "<< norm2(c_res) <<std::endl;
+
+  std::cout<<GridLogMessage<<"Little dop : "<<norm2(c_res)<<std::endl;
+  //  std::cout<<GridLogMessage<<" Little "<< c_res<<std::endl;
+
+  std::cout<<GridLogMessage<<"Big dop in subspace : "<<norm2(c_proj)<<std::endl;
+  //  std::cout<<GridLogMessage<<" Big "<< c_proj<<std::endl;
+  c_proj = c_proj - c_res;
+  std::cout<<GridLogMessage<<" ldop error: "<<norm2(c_proj)<<std::endl;
+  //  std::cout<<GridLogMessage<<" error "<< c_proj<<std::endl;
+
+
+  /**********
+   * Some solvers
+   **********
+   */
+
+  // CG
+  {
+    MdagMLinearOperator<WilsonFermionD,LatticeFermion> HermOp(Dw);
+    ConjugateGradient<LatticeFermion> CG(1.0e-8,10000);
+    Dw.Mdag(src,precsrc);
+    CG(HermOp,precsrc,result);
+    result=Zero();
+  }
+ 
+  ///////////////////////////////////////
+  // Coarse grid solver test
+  ///////////////////////////////////////
+
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Coarse Grid Solve -- Level 3 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<CoarseVector> simple;
+  NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOp);
+  ShiftedNonHermitianLinearOperator<LittleDiracOperator,CoarseVector> ShiftedLinOpCoarse(LittleDiracOp,0.001);
+  //  ShiftedNonHermitianLinearOperator<LittleDiracOperator,CoarseVector> ShiftedLinOpCoarse(LittleDiracOp,0.01);
+  //  ShiftedNonHermitianLinearOperator<LittleDiracOperator,CoarseVector> ShiftedLinOpCoarse(LinOpCoarse,0.001);
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-4, 100, LinOpCoarse,simple,10,10); 
+  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-1, 100, LinOpCoarse,simple,30,30); 
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(2.0e-1, 50, ShiftedLinOpCoarse,simple,50,50); 
+  L2PGCR.Level(3);
+  c_res=Zero();
+  L2PGCR(c_src,c_res);
+
+  ////////////////////////////////////////
+  // Fine grid smoother
+  ////////////////////////////////////////
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Fine Grid Smoother -- Level 2 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<LatticeFermionD> simple_fine;
+
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> SmootherGCR(0.1,1,ShiftedLinOpDw,simple_fine,6,6);
+  SmootherGCR.Level(2);
+  
+  LatticeFermionD f_src(FGrid);
+  LatticeFermionD f_res(FGrid);
+
+  f_src = one;  // 1 in every element for vector 1.
+  f_res=Zero();
+  SmootherGCR(f_src,f_res);
+
+  typedef MGPreconditioner<vSpinColourVector,  vTComplex,nbasis> TwoLevelMG;
+
+  TwoLevelMG TwoLevelPrecon(Aggregates,
+			    LinOpDw,
+			    simple_fine,
+			    SmootherGCR,
+			    LinOpCoarse,
+			    L2PGCR);
+  
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,1000,LinOpDw,TwoLevelPrecon,16,16);
+  L1PGCR.Level(1);
+
+  f_res=Zero();
+  L1PGCR(f_src,f_res);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage << "Done "<< std::endl;
+
+  Grid_finalize();
+  return 0;
+}

tests/debug/Test_general_coarse_wilson_svd.cc

@@ -0,0 +1,320 @@
+/*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_padded_cell.cc
+
+    Copyright (C) 2023
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+#include <Grid/lattice/PaddedCell.h>
+#include <Grid/stencil/GeneralLocalStencil.h>
+
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidual.h>
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
+#include <Grid/algorithms/iterative/BiCGSTAB.h>
+
+using namespace std;
+using namespace Grid;
+
+template<class Fobj,class CComplex,int nbasis>
+class MGPreconditioner : public LinearFunction< Lattice<Fobj> > {
+public:
+  using LinearFunction<Lattice<Fobj> >::operator();
+
+  typedef Aggregation<Fobj,CComplex,nbasis> Aggregates;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::FineField    FineField;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseVector CoarseVector;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseMatrix CoarseMatrix;
+  typedef LinearOperatorBase<FineField>                            FineOperator;
+  typedef LinearFunction    <FineField>                            FineSmoother;
+  typedef LinearOperatorBase<CoarseVector>                         CoarseOperator;
+  typedef LinearFunction    <CoarseVector>                         CoarseSolver;
+  Aggregates     & _Aggregates;
+  FineOperator   & _FineOperator;
+  FineSmoother   & _PreSmoother;
+  FineSmoother   & _PostSmoother;
+  CoarseOperator & _CoarseOperator;
+  CoarseSolver   & _CoarseSolve;
+
+  int    level;  void Level(int lv) {level = lv; };
+
+  MGPreconditioner(Aggregates &Agg,
+		   FineOperator &Fine,
+		   FineSmoother &PreSmoother,
+		   FineSmoother &PostSmoother,
+		   CoarseOperator &CoarseOperator_,
+		   CoarseSolver &CoarseSolve_)
+    : _Aggregates(Agg),
+      _FineOperator(Fine),
+      _PreSmoother(PreSmoother),
+      _PostSmoother(PostSmoother),
+      _CoarseOperator(CoarseOperator_),
+      _CoarseSolve(CoarseSolve_),
+      level(1)  {  }
+
+  virtual void operator()(const FineField &in, FineField & out) 
+  {
+    GridBase *CoarseGrid = _Aggregates.CoarseGrid;
+    //    auto CoarseGrid = _CoarseOperator.Grid();
+    CoarseVector Csrc(CoarseGrid);
+    CoarseVector Csol(CoarseGrid);
+    FineField vec1(in.Grid());
+    FineField vec2(in.Grid());
+
+    std::cout<<GridLogMessage << "Calling PreSmoother " <<std::endl;
+
+    //    std::cout<<GridLogMessage << "Calling PreSmoother input residual "<<norm2(in) <<std::endl;
+    double t;
+    // Fine Smoother
+    //    out = in;
+    out = Zero();
+    t=-usecond();
+    _PreSmoother(in,out);
+    t+=usecond();
+
+    std::cout<<GridLogMessage << "PreSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Update the residual
+    _FineOperator.Op(out,vec1);  sub(vec1, in ,vec1);   
+    //    std::cout<<GridLogMessage <<"Residual-1 now " <<norm2(vec1)<<std::endl;
+
+    // Fine to Coarse 
+    t=-usecond();
+    _Aggregates.ProjectToSubspace  (Csrc,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Project to coarse took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse correction
+    t=-usecond();
+    Csol = Zero();
+    _CoarseSolve(Csrc,Csol);
+    //Csol=Zero();
+    t+=usecond();
+    std::cout<<GridLogMessage << "Coarse solve took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse to Fine
+    t=-usecond();  
+    //    _CoarseOperator.PromoteFromSubspace(_Aggregates,Csol,vec1);
+    _Aggregates.PromoteFromSubspace(Csol,vec1); 
+    add(out,out,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Promote to this level took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Residual
+    _FineOperator.Op(out,vec1);  sub(vec1 ,in , vec1);  
+    //    std::cout<<GridLogMessage <<"Residual-2 now " <<norm2(vec1)<<std::endl;
+
+    // Fine Smoother
+    t=-usecond();
+    //    vec2=vec1;
+    vec2=Zero();
+    _PostSmoother(vec1,vec2);
+    t+=usecond();
+    std::cout<<GridLogMessage << "PostSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    add( out,out,vec2);
+    std::cout<<GridLogMessage << "Done " <<std::endl;
+  }
+};
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=16;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+
+  GridCartesian         * FGrid   = UGrid;
+  GridRedBlackCartesian * FrbGrid = UrbGrid;
+
+  // Construct a coarsened grid
+  Coordinate clatt = GridDefaultLatt();
+  for(int d=0;d<clatt.size();d++){
+    clatt[d] = clatt[d]/2;
+    //    clatt[d] = clatt[d]/4;
+  }
+  GridCartesian *Coarse4d =  SpaceTimeGrid::makeFourDimGrid(clatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());;
+
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> cseeds({5,6,7,8});
+  GridParallelRNG          RNG4(UGrid);   RNG4.SeedFixedIntegers(seeds4);
+  GridParallelRNG          CRNG(Coarse4d);CRNG.SeedFixedIntegers(cseeds);
+
+  LatticeFermion    src(FGrid); random(RNG4,src);
+  LatticeFermion result(FGrid); result=Zero();
+  LatticeFermion    ref(FGrid); ref=Zero();
+  LatticeFermion    tmp(FGrid);
+  LatticeFermion    err(FGrid);
+  LatticeGaugeField Umu(UGrid);
+
+  FieldMetaData header;
+  std::string file("ckpoint_lat");
+  NerscIO::readConfiguration(Umu,header,file);
+  
+  RealD csw =0.0;
+  RealD mass=-0.92;
+
+  WilsonCloverFermionD Dw(Umu,*UGrid,*UrbGrid,mass,csw,csw);
+
+  const int nbasis = 20;
+  const int cb = 0 ;
+  LatticeFermion prom(FGrid);
+
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,2*nbasis> LittleDiracOperator;
+  typedef LittleDiracOperator::CoarseVector CoarseVector;
+
+  NearestStencilGeometry4D geom(Coarse4d);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+ 
+  // Warning: This routine calls Linop.Op, not LinOpo.HermOp
+  typedef Aggregation<vSpinColourVector,vTComplex,nbasis> Subspace;
+  Subspace Aggregates(Coarse4d,FGrid,cb);
+
+  MdagMLinearOperator<WilsonCloverFermionD,LatticeFermion> MdagMOpDw(Dw);
+  NonHermitianLinearOperator<WilsonCloverFermionD,LatticeFermion> LinOpDw(Dw);
+  ShiftedNonHermitianLinearOperator<WilsonCloverFermionD,LatticeFermion> ShiftedLinOpDw(Dw,0.5);
+
+  //  Aggregates.CreateSubspaceGCR(RNG4,
+  //			       LinOpDw,
+  //			       nbasis);
+  Aggregates.CreateSubspace(RNG4,MdagMOpDw,nbasis);
+  
+  typedef Aggregation<vSpinColourVector,vTComplex,2*nbasis> CombinedSubspace;
+  CombinedSubspace CombinedUV(Coarse4d,UGrid,cb);
+  for(int b=0;b<nbasis;b++){
+    Gamma G5(Gamma::Algebra::Gamma5);
+    CombinedUV.subspace[b]        = Aggregates.subspace[b];
+    CombinedUV.subspace[b+nbasis] = G5*Aggregates.subspace[b];
+  }
+
+  LittleDiracOperator LittleDiracOp(geom,FGrid,Coarse4d);
+  LittleDiracOp.CoarsenOperator(LinOpDw,CombinedUV);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"Testing coarsened operator "<<std::endl;
+  
+  CoarseVector c_src (Coarse4d);
+  CoarseVector c_res (Coarse4d);
+  CoarseVector c_proj(Coarse4d);
+
+  std::vector<LatticeFermion> subspace(2*nbasis,FGrid);
+  subspace=CombinedUV.subspace;
+
+  Complex one(1.0);
+  c_src = one;  // 1 in every element for vector 1.
+  blockPromote(c_src,err,subspace);
+
+  prom=Zero();
+  for(int b=0;b<2*nbasis;b++){
+    prom=prom+subspace[b];
+  }
+  err=err-prom; 
+  std::cout<<GridLogMessage<<"Promoted back from subspace: err "<<norm2(err)<<std::endl;
+  std::cout<<GridLogMessage<<"c_src "<<norm2(c_src)<<std::endl;
+  std::cout<<GridLogMessage<<"prom  "<<norm2(prom)<<std::endl;
+
+  LinOpDw.Op(prom,tmp);
+  blockProject(c_proj,tmp,subspace);
+  std::cout<<GridLogMessage<<" Called Big Dirac Op "<<norm2(tmp)<<std::endl;
+
+  LittleDiracOp.M(c_src,c_res);
+  std::cout<<GridLogMessage<<" Called Little Dirac Op c_src "<< norm2(c_src) << "  c_res "<< norm2(c_res) <<std::endl;
+
+  std::cout<<GridLogMessage<<"Little dop : "<<norm2(c_res)<<std::endl;
+  //  std::cout<<GridLogMessage<<" Little "<< c_res<<std::endl;
+
+  std::cout<<GridLogMessage<<"Big dop in subspace : "<<norm2(c_proj)<<std::endl;
+  //  std::cout<<GridLogMessage<<" Big "<< c_proj<<std::endl;
+  c_proj = c_proj - c_res;
+  std::cout<<GridLogMessage<<" ldop error: "<<norm2(c_proj)<<std::endl;
+  //  std::cout<<GridLogMessage<<" error "<< c_proj<<std::endl;
+
+
+  /**********
+   * Some solvers
+   **********
+   */
+
+  ///////////////////////////////////////
+  // Coarse grid solver test
+  ///////////////////////////////////////
+
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Coarse Grid Solve -- Level 3 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<CoarseVector> simple;
+  NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOp);
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-4, 100, LinOpCoarse,simple,10,10); 
+  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-2, 100, LinOpCoarse,simple,30,30); 
+  L2PGCR.Level(3);
+  c_res=Zero();
+  L2PGCR(c_src,c_res);
+
+  ////////////////////////////////////////
+  // Fine grid smoother
+  ////////////////////////////////////////
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Fine Grid Smoother -- Level 2 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<LatticeFermionD> simple_fine;
+
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> SmootherGCR(0.01,1,ShiftedLinOpDw,simple_fine,4,4);
+  SmootherGCR.Level(2);
+  
+  LatticeFermionD f_src(FGrid);
+  LatticeFermionD f_res(FGrid);
+
+  f_src = one;  // 1 in every element for vector 1.
+  f_res=Zero();
+  SmootherGCR(f_src,f_res);
+
+  typedef MGPreconditioner<vSpinColourVector,  vTComplex,2*nbasis> TwoLevelMG;
+
+  TwoLevelMG TwoLevelPrecon(CombinedUV,
+			    LinOpDw,
+			    simple_fine,
+			    SmootherGCR,
+			    LinOpCoarse,
+			    L2PGCR);
+  
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,1000,LinOpDw,TwoLevelPrecon,32,32);
+  L1PGCR.Level(1);
+
+  f_res=Zero();
+  L1PGCR(f_src,f_res);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage << "Done "<< std::endl;
+
+  Grid_finalize();
+  return 0;
+}

tests/debug/Test_general_coarse_wilson_svd_no5g.cc

@@ -0,0 +1,312 @@
+/*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_padded_cell.cc
+
+    Copyright (C) 2023
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+#include <Grid/lattice/PaddedCell.h>
+#include <Grid/stencil/GeneralLocalStencil.h>
+
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidual.h>
+#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
+#include <Grid/algorithms/iterative/BiCGSTAB.h>
+
+using namespace std;
+using namespace Grid;
+
+template<class Fobj,class CComplex,int nbasis>
+class MGPreconditioner : public LinearFunction< Lattice<Fobj> > {
+public:
+  using LinearFunction<Lattice<Fobj> >::operator();
+
+  typedef Aggregation<Fobj,CComplex,nbasis> Aggregates;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::FineField    FineField;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseVector CoarseVector;
+  typedef typename Aggregation<Fobj,CComplex,nbasis>::CoarseMatrix CoarseMatrix;
+  typedef LinearOperatorBase<FineField>                            FineOperator;
+  typedef LinearFunction    <FineField>                            FineSmoother;
+  typedef LinearOperatorBase<CoarseVector>                         CoarseOperator;
+  typedef LinearFunction    <CoarseVector>                         CoarseSolver;
+  Aggregates     & _Aggregates;
+  FineOperator   & _FineOperator;
+  FineSmoother   & _PreSmoother;
+  FineSmoother   & _PostSmoother;
+  CoarseOperator & _CoarseOperator;
+  CoarseSolver   & _CoarseSolve;
+
+  int    level;  void Level(int lv) {level = lv; };
+
+  MGPreconditioner(Aggregates &Agg,
+		   FineOperator &Fine,
+		   FineSmoother &PreSmoother,
+		   FineSmoother &PostSmoother,
+		   CoarseOperator &CoarseOperator_,
+		   CoarseSolver &CoarseSolve_)
+    : _Aggregates(Agg),
+      _FineOperator(Fine),
+      _PreSmoother(PreSmoother),
+      _PostSmoother(PostSmoother),
+      _CoarseOperator(CoarseOperator_),
+      _CoarseSolve(CoarseSolve_),
+      level(1)  {  }
+
+  virtual void operator()(const FineField &in, FineField & out) 
+  {
+    GridBase *CoarseGrid = _Aggregates.CoarseGrid;
+    //    auto CoarseGrid = _CoarseOperator.Grid();
+    CoarseVector Csrc(CoarseGrid);
+    CoarseVector Csol(CoarseGrid);
+    FineField vec1(in.Grid());
+    FineField vec2(in.Grid());
+
+    std::cout<<GridLogMessage << "Calling PreSmoother " <<std::endl;
+
+    //    std::cout<<GridLogMessage << "Calling PreSmoother input residual "<<norm2(in) <<std::endl;
+    double t;
+    // Fine Smoother
+    //    out = in;
+    out = Zero();
+    t=-usecond();
+    _PreSmoother(in,out);
+    t+=usecond();
+
+    std::cout<<GridLogMessage << "PreSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Update the residual
+    _FineOperator.Op(out,vec1);  sub(vec1, in ,vec1);   
+    //    std::cout<<GridLogMessage <<"Residual-1 now " <<norm2(vec1)<<std::endl;
+
+    // Fine to Coarse 
+    t=-usecond();
+    _Aggregates.ProjectToSubspace  (Csrc,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Project to coarse took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse correction
+    t=-usecond();
+    Csol = Zero();
+    _CoarseSolve(Csrc,Csol);
+    //Csol=Zero();
+    t+=usecond();
+    std::cout<<GridLogMessage << "Coarse solve took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Coarse to Fine
+    t=-usecond();  
+    //    _CoarseOperator.PromoteFromSubspace(_Aggregates,Csol,vec1);
+    _Aggregates.PromoteFromSubspace(Csol,vec1); 
+    add(out,out,vec1);
+    t+=usecond();
+    std::cout<<GridLogMessage << "Promote to this level took "<< t/1000.0<< "ms" <<std::endl;
+
+    // Residual
+    _FineOperator.Op(out,vec1);  sub(vec1 ,in , vec1);  
+    //    std::cout<<GridLogMessage <<"Residual-2 now " <<norm2(vec1)<<std::endl;
+
+    // Fine Smoother
+    t=-usecond();
+    //    vec2=vec1;
+    vec2=Zero();
+    _PostSmoother(vec1,vec2);
+    t+=usecond();
+    std::cout<<GridLogMessage << "PostSmoother took "<< t/1000.0<< "ms" <<std::endl;
+
+    add( out,out,vec2);
+    std::cout<<GridLogMessage << "Done " <<std::endl;
+  }
+};
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=16;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+
+  GridCartesian         * FGrid   = UGrid;
+  GridRedBlackCartesian * FrbGrid = UrbGrid;
+
+  // Construct a coarsened grid
+  Coordinate clatt = GridDefaultLatt();
+  for(int d=0;d<clatt.size();d++){
+    clatt[d] = clatt[d]/2;
+    //    clatt[d] = clatt[d]/4;
+  }
+  GridCartesian *Coarse4d =  SpaceTimeGrid::makeFourDimGrid(clatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());;
+
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> cseeds({5,6,7,8});
+  GridParallelRNG          RNG4(UGrid);   RNG4.SeedFixedIntegers(seeds4);
+  GridParallelRNG          CRNG(Coarse4d);CRNG.SeedFixedIntegers(cseeds);
+
+  LatticeFermion    src(FGrid); random(RNG4,src);
+  LatticeFermion result(FGrid); result=Zero();
+  LatticeFermion    ref(FGrid); ref=Zero();
+  LatticeFermion    tmp(FGrid);
+  LatticeFermion    err(FGrid);
+  LatticeGaugeField Umu(UGrid);
+
+  FieldMetaData header;
+  std::string file("ckpoint_lat");
+  NerscIO::readConfiguration(Umu,header,file);
+  
+  RealD csw =0.0;
+  RealD mass=-0.92;
+
+  WilsonCloverFermionD Dw(Umu,*UGrid,*UrbGrid,mass,csw,csw);
+
+  const int nbasis = 40;
+  const int cb = 0 ;
+  LatticeFermion prom(FGrid);
+
+  typedef GeneralCoarsenedMatrix<vSpinColourVector,vTComplex,nbasis> LittleDiracOperator;
+  typedef LittleDiracOperator::CoarseVector CoarseVector;
+
+  NearestStencilGeometry4D geom(Coarse4d);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+ 
+  // Warning: This routine calls Linop.Op, not LinOpo.HermOp
+  typedef Aggregation<vSpinColourVector,vTComplex,nbasis> Subspace;
+  Subspace Aggregates(Coarse4d,FGrid,cb);
+
+  MdagMLinearOperator<WilsonCloverFermionD,LatticeFermion> MdagMOpDw(Dw);
+  NonHermitianLinearOperator<WilsonCloverFermionD,LatticeFermion> LinOpDw(Dw);
+  ShiftedNonHermitianLinearOperator<WilsonCloverFermionD,LatticeFermion> ShiftedLinOpDw(Dw,0.5);
+
+  //  Aggregates.CreateSubspaceGCR(RNG4,
+  //			       LinOpDw,
+  //			       nbasis);
+  Aggregates.CreateSubspace(RNG4,MdagMOpDw,nbasis);
+
+  LittleDiracOperator LittleDiracOp(geom,FGrid,Coarse4d);
+  LittleDiracOp.CoarsenOperator(LinOpDw,Aggregates);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"Testing coarsened operator "<<std::endl;
+  
+  CoarseVector c_src (Coarse4d);
+  CoarseVector c_res (Coarse4d);
+  CoarseVector c_proj(Coarse4d);
+
+  std::vector<LatticeFermion> subspace(nbasis,FGrid);
+  subspace=Aggregates.subspace;
+
+  Complex one(1.0);
+  c_src = one;  // 1 in every element for vector 1.
+  blockPromote(c_src,err,subspace);
+
+  prom=Zero();
+  for(int b=0;b<nbasis;b++){
+    prom=prom+subspace[b];
+  }
+  err=err-prom; 
+  std::cout<<GridLogMessage<<"Promoted back from subspace: err "<<norm2(err)<<std::endl;
+  std::cout<<GridLogMessage<<"c_src "<<norm2(c_src)<<std::endl;
+  std::cout<<GridLogMessage<<"prom  "<<norm2(prom)<<std::endl;
+
+  LinOpDw.Op(prom,tmp);
+  blockProject(c_proj,tmp,subspace);
+  std::cout<<GridLogMessage<<" Called Big Dirac Op "<<norm2(tmp)<<std::endl;
+
+  LittleDiracOp.M(c_src,c_res);
+  std::cout<<GridLogMessage<<" Called Little Dirac Op c_src "<< norm2(c_src) << "  c_res "<< norm2(c_res) <<std::endl;
+
+  std::cout<<GridLogMessage<<"Little dop : "<<norm2(c_res)<<std::endl;
+  //  std::cout<<GridLogMessage<<" Little "<< c_res<<std::endl;
+
+  std::cout<<GridLogMessage<<"Big dop in subspace : "<<norm2(c_proj)<<std::endl;
+  //  std::cout<<GridLogMessage<<" Big "<< c_proj<<std::endl;
+  c_proj = c_proj - c_res;
+  std::cout<<GridLogMessage<<" ldop error: "<<norm2(c_proj)<<std::endl;
+  //  std::cout<<GridLogMessage<<" error "<< c_proj<<std::endl;
+
+
+  /**********
+   * Some solvers
+   **********
+   */
+
+  ///////////////////////////////////////
+  // Coarse grid solver test
+  ///////////////////////////////////////
+
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Coarse Grid Solve -- Level 3 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<CoarseVector> simple;
+  NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOp);
+  //  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-4, 100, LinOpCoarse,simple,10,10); 
+  PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>  L2PGCR(1.0e-2, 100, LinOpCoarse,simple,30,30); 
+  L2PGCR.Level(3);
+  c_res=Zero();
+  L2PGCR(c_src,c_res);
+
+  ////////////////////////////////////////
+  // Fine grid smoother
+  ////////////////////////////////////////
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  std::cout<<GridLogMessage<<" Fine Grid Smoother -- Level 2 "<<std::endl;
+  std::cout<<GridLogMessage<<"******************* "<<std::endl;
+  TrivialPrecon<LatticeFermionD> simple_fine;
+
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> SmootherGCR(0.01,1,ShiftedLinOpDw,simple_fine,6,6);
+  SmootherGCR.Level(2);
+  
+  LatticeFermionD f_src(FGrid);
+  LatticeFermionD f_res(FGrid);
+
+  f_src = one;  // 1 in every element for vector 1.
+  f_res=Zero();
+  SmootherGCR(f_src,f_res);
+
+  typedef MGPreconditioner<vSpinColourVector,  vTComplex,nbasis> TwoLevelMG;
+
+  TwoLevelMG TwoLevelPrecon(Aggregates,
+			    LinOpDw,
+			    simple_fine,
+			    SmootherGCR,
+			    LinOpCoarse,
+			    L2PGCR);
+  
+  PrecGeneralisedConjugateResidualNonHermitian<LatticeFermion> L1PGCR(1.0e-8,1000,LinOpDw,TwoLevelPrecon,32,32);
+  L1PGCR.Level(1);
+
+  f_res=Zero();
+  L1PGCR(f_src,f_res);
+
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage<<"*******************************************"<<std::endl;
+  std::cout<<GridLogMessage<<std::endl;
+  std::cout<<GridLogMessage << "Done "<< std::endl;
+
+  Grid_finalize();
+  return 0;
+}

tests/debug/Test_padded_cell_staple.cc

@@ -490,7 +490,7 @@ public:
 
 	    }
 	  }
-	  GRID_ASSERT(s==nshift);
+	  assert(s==nshift);
 	  coalescedWrite(gStaple_v[ss],stencil_ss);
 	}
 	);

tests/disable_tests_without_instantiations.h

@@ -0,0 +1,16 @@
+#include <Grid/Grid.h>
+
+#pragma once
+
+#ifndef ENABLE_FERMION_INSTANTIATIONS
+#include <iostream>
+
+int main(void) {
+  std::cout << "This build of Grid was configured to exclude fermion instantiations, "
+	    << "which this test relies on. "
+	    << "Please reconfigure and rebuild Grid with --enable-fermion-instantiations"
+	    << "to run this test."
+	    << std::endl;
+  return 1;
+}
+#endif

visualisation/CLAUDE.md

@@ -0,0 +1,171 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## What This Is
+
+VTK-based visualisation and analysis tools for Grid lattice QCD eigenvector density and HMC force data. All programmes link against both Grid (for reading Scidac/ILDG lattice files) and VTK (for rendering).
+
+## Build
+
+```bash
+cd /Users/peterboyle/QCD/AmSC/Grid/visualisation/build
+cmake .. -DVTK_DIR=$HOME/QCD/vtk/VTK-9.4.2-install/lib/cmake/vtk-9.4
+make <target>    # e.g. make ControlledVisualise5D
+```
+
+All executables are built as macOS bundles (`.app`) except `ForceAnalysis`, `FindPeak`, and `DumpField`.
+
+## Programmes
+
+### ControlledVisualise5D
+
+Interactive VTK renderer for 5D DWF eigenvector density (`LatticeComplexD`). Driven via named pipe `/tmp/visualise_cmd`.
+
+**Launch script**: `/Volumes/X9Pro/visualisation/Grid/visualisation/build/Hdwf_1_long/visualise_controlled.sh`
+
+**Wire protocol** (one command per line to `/tmp/visualise_cmd`):
+
+| Command | Effect |
+|---------|--------|
+| `file <N>` / `file +N` / `file -N` | Jump to file by index or relative |
+| `slice <dim> <N>` / `+N` / `-N` | Set or shift slice coordinate in dimension dim |
+| `spin <deg>` | Continuous azimuth rotation at deg/tick (100ms tick); `spin 0` stops |
+| `azimuth <deg>` | Single azimuth rotation step |
+| `elevation <deg>` | Single elevation rotation step |
+| `zoom <factor>` | Camera dolly (>1 = in) |
+| `iso <value>` | Isosurface threshold in RMS units |
+| `status` | Print current state |
+| `quit` | Exit |
+
+**Dimension indices for 5D DWF grid** (`--grid 48.32.32.32.32`):
+
+| dim | axis | size |
+|-----|------|------|
+| 0   | s (Ls) | 48 |
+| 1   | x    | 32   |
+| 2   | y    | 32   |
+| 3   | z    | 32   |
+| 4   | t    | 32   |
+
+**MD time mapping** for trajectory 702 (241 files, τ=3.3–4.0):
+- File index N → τ = 3.300000 + N × (1/480)
+- τ → file index = round((τ − 3.3) × 480)
+
+**Display axes**: `--xyz 0.3.4` shows s, z, t. The `--slice` argument sets initial values for all dims; dims not in `--xyz`, `--sum`, or `--loop` are the fixed slice dimensions (x=dim1, y=dim2 with `--xyz 0.3.4`).
+
+**Spin**: Implemented via `g_spinDeg` global applied on every 100ms poll timer tick inside `CommandHandler::Execute()`. Does not flood the pipe.
+
+### FindPeak
+
+Reads a `LatticeComplexD` Scidac file, prints the top-N sites by real value to stderr.
+
+```bash
+./FindPeak --grid 48.32.32.32.32 --mpi 1.1.1.1.1 <file> 2>peaks.txt
+```
+
+Key result: At τ=3.670833 the tunneling hotsite on the s=0 wall is (x=21, y=24, z=2, t=23).
+
+### ForceAnalysis
+
+Reads 4D `LatticeComplexD` force snapshot files (Shuhei's snapshots at `/Volumes/X9Pro/visualisation/Shuhei/snapshots/`). Outputs TSV of RMS and hotsite value per file to stderr.
+
+```bash
+./ForceAnalysis --grid 32.32.32.32 --mpi 1.1.1 --hotsite 21.24.2.23 \
+    <files...> 2>force.tsv 1>/dev/null
+```
+
+Force components: `Gauge_lat`, `Gauge_smr`, `Jacobian_smr`, `Ferm0047_lat`, `Ferm0047_smr`.
+
+### DumpField
+
+Reads a `LatticeComplexD` and dumps via Grid's `<<` operator to stdout for verification.
+
+### TranscriptToVideo
+
+Renders a conversation transcript to an MP4 video (1280×720, 10 fps) with a typewriter animation effect, scrolling history, and optional captions. Does **not** link against Grid — pure VTK only.
+
+#### Transcript format
+
+```
+[USER] First question text, possibly
+continuing on the next line.
+
+A blank line within a turn creates a paragraph break (visual spacer).
+
+[ASSISTANT] Response text.
+Multiple continuation lines are preserved
+as separate display lines, not merged.
+
+[CAPTION] Caption text shown at bottom of screen in white italic.
+[CAPTION]    (whitespace-only body clears the caption)
+[USER] Next question...
+```
+
+- Lines beginning `[USER]`, `[ASSISTANT]`, `[CAPTION]` start a new turn.
+- Continuation lines (no `[TAG]` prefix) are joined with `\n` — each becomes its own wrapped display line.
+- Blank lines within a turn become paragraph-break spacers.
+- Markdown emphasis markers (`**`, `*`, `` ` ``) are stripped automatically.
+- UTF-8 smart quotes, em-dashes, ellipses, arrows are transliterated to ASCII.
+
+#### Usage
+
+```bash
+cd /Users/peterboyle/QCD/AmSC/Grid/visualisation/build
+# Set runtime library paths first (see Runtime Environment below)
+./TranscriptToVideo <transcript_file> <output.mp4>
+```
+
+Transcript files live in `/Users/peterboyle/QCD/AmSC/Grid/visualisation/` (e.g. `transcript`, `transcript2`, `transcript3`).
+
+#### Visual layout
+
+| Element | Detail |
+|---------|--------|
+| Background | Near-black navy `(0.04, 0.04, 0.10)` |
+| `[USER]` text | Gold `(1.00, 0.84, 0.00)` |
+| `[ASSISTANT]` text | Steel blue `(0.68, 0.85, 0.90)` |
+| History | Up to 18 lines; brightness fades linearly from 0.85 (newest) to 0.20 (oldest) |
+| Caption | Arial italic 20pt white with shadow, centred at bottom |
+| Progress bar | Blue, top of frame |
+| Typewriter speed | 50 chars/sec (5 chars/frame at 10 fps) |
+| Pause between lines | 3 frames (0.3 s) |
+| Word-wrap column | 60 chars (body only, after prefix) |
+
+#### Key implementation notes
+
+- **Persistent render context**: a single `vtkRenderWindow` is created once and reused for all frames. Creating a new window per frame exhausts the macOS Metal GPU command buffer after ~33 frames (`MTLCommandBufferErrorDomain Code=8`).
+- **`SanitiseASCII()`**: replaces multi-byte UTF-8 sequences before passing to VTK's font renderer (which crashes on non-ASCII input).
+- Output format is MP4 via `vtkFFMPEGWriter`. `SetOffScreenRendering(1)` is required for headless rendering.
+
+## Runtime Environment
+
+All executables in `build/` require Spack-installed HDF5/FFTW/GMP/MPFR on the dynamic linker path:
+
+```bash
+SPACK=/Users/peterboyle/QCD/Spack/spack/opt/spack/darwin-m1
+export DYLD_LIBRARY_PATH=\
+$SPACK/hdf5-1.14.6-2265ms4kymgw6hcnwi6vqehslyfv74t4/lib:\
+$SPACK/fftw-3.3.10-aznn6h3nac5cycidlhrhgjxvntpcbg57/lib:\
+$SPACK/gmp-6.3.0-cwiz4n7ww33fnb3aban2iup4orcr6c7i/lib:\
+$SPACK/mpfr-4.2.1-exgbz4qshmet6tmmuttdewdlunfvtrlb/lib:\
+$DYLD_LIBRARY_PATH
+```
+
+(These paths are also set by the ControlledVisualise5D launch script.)
+
+## Key Physics Context
+
+See `/Volumes/X9Pro/visualisation/analysis_notes_20260407.md` for full analysis. Summary:
+
+- Near-zero mode of H_DWF localises on the two walls (s=0 and s=47) of the 5D domain wall geometry
+- Topology change transfers norm between walls, mediated by a near-zero mode of H_w (Hermitian Wilson at m=−1.8)
+- Tunneling hotsite on s=0 wall: (x=21, y=24, z=2, t=23); s=47 wall: (x=4, y=8, z=0, t=20)
+- Light fermion pseudofermion force (Ferm0047_smr) peaks at ~20× RMS at the hotsite during tunneling — this is the restoring force that causes topological bounces
+
+## Grid/VTK interaction notes
+
+- Grid log messages go to stdout; all data output in analysis programmes uses stderr to avoid interleaving
+- `TensorRemove()` is required when extracting a scalar from `peekSite()` result: `real(TensorRemove(peekSite(field, site)))`
+- For runtime-determined grid dimensionality use `GridDefaultSimd(latt_size.size(), vComplex::Nsimd())`
+- DYLD_LIBRARY_PATH must include Spack HDF5/FFTW/GMP/MPFR paths (see launch script)

visualisation/ControlledVisualise5D.cxx

@@ -0,0 +1,891 @@
+// ControlledVisualise5D.cxx
+// Derived from Visualise5D.cxx by Peter Boyle
+//
+// A minimal-protocol rendering engine for 5D DWF eigenvector-density data.
+// Intended to be driven by an external intelligent controller (e.g. Claude)
+// that handles all natural-language interpretation and state tracking.
+//
+// Commands are sent one per line to the named pipe /tmp/visualise_cmd.
+// State is reported to stdout after every command.
+//
+// Wire protocol (all fields whitespace-separated):
+//
+//   slice <dim> <N>       set Slice[dim] = N  (0-based, wraps to lattice size)
+//   slice <dim> +<N>      increment Slice[dim] by N
+//   slice <dim> -<N>      decrement Slice[dim] by N
+//   zoom <factor>         camera Dolly by factor  (>1 = in, <1 = out)
+//   iso <value>           set isosurface threshold to <value> x RMS
+//   file <index>          jump to file by absolute index
+//   file +<N>             advance N files
+//   file -<N>             go back N files
+//   render                force a render with current state
+//   status                print current state to stdout
+//   quit                  exit cleanly
+//
+// Dimension indices for 5D DWF grid (e.g. --grid 48.32.32.32.32):
+//   s=0 (Ls)  x=1  y=2  z=3  t=4
+// For a 4D grid (--grid 32.32.32.32):
+//   x=0  y=1  z=2  t=3
+
+#include <vtkActor.h>
+#include <vtkCamera.h>
+#include <vtkNamedColors.h>
+#include <vtkNew.h>
+#include <vtkOutlineFilter.h>
+#include <vtkPolyDataMapper.h>
+#include <vtkProperty.h>
+#include <vtkRenderWindow.h>
+#include <vtkRenderWindowInteractor.h>
+#include <vtkRenderer.h>
+#include <vtkStripper.h>
+#include <vtkImageData.h>
+#include <vtkCallbackCommand.h>
+#include <vtkTextActor.h>
+#include <vtkTextProperty.h>
+#include <vtkProperty2D.h>
+#include <vtkWindowToImageFilter.h>
+
+#define MPEG
+#ifdef MPEG
+#include <vtkFFMPEGWriter.h>
+#endif
+
+#include <array>
+#include <string>
+#include <vector>
+#include <queue>
+#include <mutex>
+#include <thread>
+#include <atomic>
+#include <sstream>
+#include <iostream>
+#include <fstream>
+#include <cmath>
+#include <cstdlib>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <Grid/Grid.h>
+
+#define USE_FLYING_EDGES
+#ifdef USE_FLYING_EDGES
+#include <vtkFlyingEdges3D.h>
+typedef vtkFlyingEdges3D isosurface;
+#else
+#include <vtkMarchingCubes.h>
+typedef vtkMarchingCubes isosurface;
+#endif
+
+#define CMD_PIPE "/tmp/visualise_cmd"
+
+static int g_mpeg      = 0;
+static int g_framerate = 10;
+
+// ─── Thread-safe command queue ────────────────────────────────────────────────
+static std::queue<std::string> g_cmdQueue;
+static std::mutex              g_cmdMutex;
+static std::atomic<bool>       g_running{true};
+static double                  g_spinDeg = 0.0;   // degrees per poll tick; 0 = stopped
+
+// ─── MPEG recording state ─────────────────────────────────────────────────────
+static bool                        g_recording   = false;
+static vtkFFMPEGWriter*            g_mpegWriter  = nullptr;
+static vtkWindowToImageFilter*     g_imageFilter = nullptr;
+static std::string                 g_recordingFile;   // AVI filename for mux step
+
+// ─── Audio state (PCM audio track, synced to video frames) ───────────────────
+static const int    AUDIO_RATE        = 44100;
+static const double BEEP_FREQ         = 800.0;
+static const int    BEEP_SAMPLES      = AUDIO_RATE * 4 / 100;  // 40ms beep
+static std::vector<int16_t> g_audioBuffer;
+static int          g_beepRemaining   = 0;
+static double       g_beepPhase       = 0.0;
+static int          g_samplesPerFrame = AUDIO_RATE / 10; // updated at record start
+
+// Write one video frame worth of audio samples (beep or silence) to the buffer.
+static void GenerateAudioFrame()
+{
+    for (int i = 0; i < g_samplesPerFrame; i++) {
+        int16_t s = 0;
+        if (g_beepRemaining > 0) {
+            int pos = BEEP_SAMPLES - g_beepRemaining;
+            double env = 1.0;
+            int fade = AUDIO_RATE / 100;  // 10ms fade
+            if (pos   < fade) env = (double)pos   / fade;
+            if (g_beepRemaining < fade) env = (double)g_beepRemaining / fade;
+            s = (int16_t)(16000.0 * env * std::sin(2.0 * M_PI * BEEP_FREQ * g_beepPhase / AUDIO_RATE));
+            g_beepPhase += 1.0;
+            --g_beepRemaining;
+        } else {
+            g_beepPhase = 0.0;
+        }
+        g_audioBuffer.push_back(s);
+    }
+}
+
+static void TriggerBeep() { g_beepRemaining = BEEP_SAMPLES; }
+
+// Simple mono 16-bit PCM WAV writer.
+static void WriteWAV(const std::string& path, const std::vector<int16_t>& buf, int rate)
+{
+    std::ofstream f(path, std::ios::binary);
+    int dataBytes  = (int)(buf.size() * 2);
+    int chunkSize  = 36 + dataBytes;
+    int byteRate   = rate * 2;
+    f.write("RIFF", 4); f.write((char*)&chunkSize, 4);
+    f.write("WAVE", 4);
+    f.write("fmt ", 4);
+    int fmtSz = 16;       f.write((char*)&fmtSz,  4);
+    int16_t pcm = 1;      f.write((char*)&pcm,    2);
+    int16_t ch  = 1;      f.write((char*)&ch,     2);
+    f.write((char*)&rate,     4);
+    f.write((char*)&byteRate, 4);
+    int16_t blk = 2;      f.write((char*)&blk, 2);
+    int16_t bps = 16;     f.write((char*)&bps, 2);
+    f.write("data", 4);   f.write((char*)&dataBytes, 4);
+    f.write((char*)buf.data(), dataBytes);
+}
+
+// Play a short audible beep on the local machine (non-blocking).
+static void PlayBeepAudible()
+{
+    system("afplay /System/Library/Sounds/Tink.aiff -v 0.4 &");
+}
+
+// ─── Grid I/O ─────────────────────────────────────────────────────────────────
+template <class T>
+void readFile(T& out, const std::string& fname)
+{
+    Grid::emptyUserRecord record;
+    Grid::ScidacReader RD;
+    RD.open(fname);
+    RD.readScidacFieldRecord(out, record);
+    RD.close();
+}
+
+using namespace Grid;
+
+// ─── Command reader thread ────────────────────────────────────────────────────
+void CommandReaderThread()
+{
+    mkfifo(CMD_PIPE, 0666);
+    std::cout << "[cmd] Listening on " << CMD_PIPE << std::endl;
+
+    while (g_running) {
+        int fd = open(CMD_PIPE, O_RDONLY | O_NONBLOCK);
+        if (fd < 0) { usleep(200000); continue; }
+
+        int flags = fcntl(fd, F_GETFL);
+        fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
+
+        char buf[4096];
+        std::string partial;
+        ssize_t n;
+        while (g_running && (n = read(fd, buf, sizeof(buf) - 1)) > 0) {
+            buf[n] = '\0';
+            partial += buf;
+            size_t pos;
+            while ((pos = partial.find('\n')) != std::string::npos) {
+                std::string line = partial.substr(0, pos);
+                if (!line.empty() && line.back() == '\r') line.pop_back();
+                if (!line.empty()) {
+                    std::lock_guard<std::mutex> lk(g_cmdMutex);
+                    g_cmdQueue.push(line);
+                }
+                partial = partial.substr(pos + 1);
+            }
+        }
+        close(fd);
+    }
+}
+
+// ─── FrameUpdater ─────────────────────────────────────────────────────────────
+class FrameUpdater : public vtkCallbackCommand
+{
+public:
+    FrameUpdater() : ffile(0), TimerCount(0), old_file(-1), timerId(-2), maxCount(-1) {}
+
+    static FrameUpdater* New() { return new FrameUpdater; }
+
+    int ffile;
+    int old_file;
+    int timerId;
+    int maxCount;
+
+    Coordinate latt;
+    Coordinate xyz_dims, xyz_ranges, g_xyz_ranges;
+    uint64_t   xyz_vol;
+    Coordinate loop_dims, loop_ranges;
+    uint64_t   loop_vol;
+    Coordinate sum_dims, sum_ranges;
+    uint64_t   sum_vol;
+    Coordinate slice_dims;
+    Coordinate Slice;
+
+    std::vector<std::string> files;
+    int        Nd;
+    GridBase*  grid;
+    Grid::LatticeComplexD* grid_data;
+
+    double rms;
+
+    vtkImageData* imageData    = nullptr;
+    vtkTextActor* text         = nullptr;
+    isosurface*   posExtractor = nullptr;
+    isosurface*   negExtractor = nullptr;
+
+    void SetGrid(GridBase* _grid)
+    {
+        grid      = _grid;
+        Nd        = grid->Nd();
+        latt      = grid->GlobalDimensions();
+        grid_data = new Grid::LatticeComplexD(grid);
+    }
+
+    void SetFiles(std::vector<std::string> list)  { files = list; old_file = -1; }
+    void SetSlice(Coordinate _Slice)              { Slice = _Slice; }
+
+    void SetSumDimensions(Coordinate _SumDims)
+    {
+        sum_dims = _SumDims; sum_ranges = Coordinate(Nd); sum_vol = 1;
+        for (int d = 0; d < Nd; d++) { sum_ranges[d] = sum_dims[d] ? latt[d] : 1; sum_vol *= sum_ranges[d]; }
+    }
+
+    void SetLoopDimensions(Coordinate _LoopDims)
+    {
+        loop_dims = _LoopDims; loop_ranges = Coordinate(Nd); loop_vol = 1;
+        for (int d = 0; d < Nd; d++) { loop_ranges[d] = loop_dims[d] ? latt[d] : 1; loop_vol *= loop_ranges[d]; }
+    }
+
+    void SetDisplayDimensions(Coordinate _xyz_dims)
+    {
+        xyz_dims = _xyz_dims; g_xyz_ranges = Coordinate(Nd); xyz_ranges = Coordinate(3); xyz_vol = 1;
+        for (int d = 0; d < 3; d++) { xyz_ranges[d] = latt[xyz_dims[d]]; xyz_vol *= xyz_ranges[d]; }
+        for (int d = 0; d < Nd; d++) {
+            g_xyz_ranges[d] = 1;
+            for (int dd = 0; dd < 3; dd++) if (xyz_dims[dd] == d) g_xyz_ranges[d] = latt[d];
+        }
+    }
+
+    void SetSliceDimensions()
+    {
+        Coordinate sd;
+        for (int d = 0; d < Nd; d++) {
+            if (g_xyz_ranges[d] > 1 || loop_dims[d] || sum_dims[d]) continue;
+            sd.push_back(d);
+        }
+        slice_dims = sd;
+        std::cout << " Slice dimensions: " << slice_dims << std::endl;
+    }
+
+    void FillImageData(int loop_idx)
+    {
+        Coordinate loop_coor;
+        Lexicographic::CoorFromIndex(loop_coor, loop_idx, loop_ranges);
+        Coordinate xyz_coor(3), g_xyz_coor(Nd), sum_coor(Nd);
+        for (uint64_t xyz = 0; xyz < xyz_vol; xyz++) {
+            Lexicographic::CoorFromIndex(xyz_coor,   xyz, xyz_ranges);
+            Lexicographic::CoorFromIndex(g_xyz_coor, xyz, g_xyz_ranges);
+            RealD val = 0.0;
+            for (uint64_t si = 0; si < sum_vol; si++) {
+                Lexicographic::CoorFromIndex(sum_coor, si, sum_ranges);
+                Coordinate site(Nd);
+                for (int d = 0; d < Nd; d++)
+                    site[d] = (sum_coor[d] + loop_coor[d] + g_xyz_coor[d] + Slice[d]) % latt[d];
+                val += real(peekSite(*grid_data, site));
+            }
+            imageData->SetScalarComponentFromDouble(xyz_coor[0], xyz_coor[1], xyz_coor[2], 0, val);
+        }
+        imageData->Modified();
+    }
+
+    // Reload if needed, fill image, update label, render — no timer advance.
+    void ForceRender(vtkRenderWindowInteractor* iren)
+    {
+        int file = ((TimerCount / (int)loop_vol) + ffile) % (int)files.size();
+        if (file != old_file) {
+            std::cout << "[render] Loading " << files[file] << std::endl;
+            readFile(*grid_data, files[file]);
+            old_file = file;
+        }
+        FillImageData(TimerCount % (int)loop_vol);
+        UpdateLabel(file, TimerCount % (int)loop_vol);
+        iren->GetRenderWindow()->Render();
+    }
+
+    virtual void Execute(vtkObject* caller, unsigned long eventId, void* callData)
+    {
+        if (vtkCommand::KeyPressEvent == eventId) {
+            vtkRenderWindowInteractor* iren = static_cast<vtkRenderWindowInteractor*>(caller);
+            std::string key = iren->GetKeySym();
+            if (slice_dims.size() > 0) {
+                int vert = slice_dims[slice_dims.size() - 1];
+                int horz = slice_dims[0];
+                if (key == "Up")    Slice[vert] = (Slice[vert] + 1) % latt[vert];
+                if (key == "Down")  Slice[vert] = (Slice[vert] + latt[vert] - 1) % latt[vert];
+                if (key == "Right") Slice[horz] = (Slice[horz] + 1) % latt[horz];
+                if (key == "Left")  Slice[horz] = (Slice[horz] + latt[horz] - 1) % latt[horz];
+            }
+            if (key == "greater") ffile = (ffile + 1) % (int)files.size();
+            if (key == "less")    ffile = (ffile - 1 + (int)files.size()) % (int)files.size();
+            ForceRender(iren);
+            return;
+        }
+
+        if (vtkCommand::TimerEvent == eventId) {
+            // timerId == -2: no animation timer (--notime), ignore all timer events
+            if (timerId < 0) return;
+            int tid = *(reinterpret_cast<int*>(callData));
+            if (tid != timerId) return;
+            int file = ((TimerCount / (int)loop_vol) + ffile) % (int)files.size();
+            if (file != old_file) { readFile(*grid_data, files[file]); old_file = file; }
+            FillImageData(TimerCount % (int)loop_vol);
+            UpdateLabel(file, TimerCount % (int)loop_vol);
+            dynamic_cast<vtkRenderWindowInteractor*>(caller)->GetRenderWindow()->Render();
+            ++TimerCount;
+            if (TimerCount >= maxCount && timerId > -1)
+                dynamic_cast<vtkRenderWindowInteractor*>(caller)->DestroyTimer(timerId);
+        }
+    }
+
+private:
+    int TimerCount;
+
+    void UpdateLabel(int file, int loop_idx)
+    {
+        Coordinate loop_coor;
+        Lexicographic::CoorFromIndex(loop_coor, loop_idx, loop_ranges);
+        // Extract tau value from filename (last '_'-delimited field)
+        const std::string& path = files[file];
+        std::string tau = path.substr(path.rfind('_') + 1);
+        std::stringstream ss;
+        ss << "tau = " << tau << "\nSlice " << Slice;
+        text->SetInput(ss.str().c_str());
+    }
+};
+
+// ─── Typewriter caption state ─────────────────────────────────────────────────
+// User caption (gold, upper line) — cleared on new user: instruction
+static std::string g_userCaptionFull;
+static size_t      g_userCaptionPos  = 0;
+// Claude caption (light blue, lower line) — cleared when user: arrives
+static std::string g_claudeCaptionFull;
+static size_t      g_claudeCaptionPos = 0;
+static int         g_captionTick = 0;
+static const int   g_captionRate = 1;   // ticks per character (1 x 100ms = 10 chars/sec)
+
+static std::string WrapText(const std::string& s, int maxCols = 45) {
+    std::istringstream words(s);
+    std::string word, line, result;
+    while (words >> word) {
+        if (!line.empty() && (int)(line.size() + 1 + word.size()) > maxCols) {
+            result += line + "\n";
+            line = word;
+        } else {
+            if (!line.empty()) line += " ";
+            line += word;
+        }
+    }
+    if (!line.empty()) result += line;
+    return result;
+}
+
+// ─── CommandHandler ───────────────────────────────────────────────────────────
+// Minimal parser for the wire protocol. Natural-language interpretation
+// is handled externally (by Claude) before commands reach this program.
+class CommandHandler : public vtkCallbackCommand
+{
+public:
+    static CommandHandler* New() { return new CommandHandler; }
+
+    FrameUpdater*               fu;
+    vtkCamera*                  camera;
+    vtkRenderer*                renderer;
+    vtkRenderWindowInteractor*  iren;
+    vtkTextActor*               captionActor     = nullptr;  // claude (light blue, lower)
+    vtkTextActor*               userCaptionActor = nullptr;  // user  (gold,       upper)
+    int    pollTimerId     = -1;
+    double isosurfaceLevel = 1.0;   // in RMS units
+
+    void CaptureFrame() {
+        if (g_recording && g_mpegWriter && g_imageFilter) {
+            GenerateAudioFrame();
+            g_imageFilter->Modified();
+            g_mpegWriter->Write();
+        }
+    }
+
+    void SetIsosurface(double level)
+    {
+        isosurfaceLevel = std::max(0.0, std::min(10.0, level));
+        fu->posExtractor->SetValue(0,  isosurfaceLevel * fu->rms);
+        fu->negExtractor->SetValue(0, -isosurfaceLevel * fu->rms);
+        fu->posExtractor->Modified();
+        fu->negExtractor->Modified();
+    }
+
+    void PrintStatus()
+    {
+        std::cout << "[status] file       = " << fu->ffile
+                  << " : " << fu->files[fu->ffile] << "\n"
+                  << "[status] Slice      = " << fu->Slice << "\n"
+                  << "[status] latt       = " << fu->latt << "\n"
+                  << "[status] isosurface = " << isosurfaceLevel
+                  << " x RMS  (" << isosurfaceLevel * fu->rms << ")" << std::endl;
+    }
+
+    // Execute one line of the wire protocol.
+    void RunLine(const std::string& line)
+    {
+        std::istringstream iss(line);
+        std::string verb;
+        if (!(iss >> verb)) return;
+
+        // ── slice <dim> <N|+N|-N> ────────────────────────────────────────────
+        if (verb == "slice") {
+            int dim; std::string valstr;
+            if (!(iss >> dim >> valstr)) { std::cout << "[cmd] slice: expected dim value" << std::endl; return; }
+            if (dim < 0 || dim >= fu->Nd) { std::cout << "[cmd] slice: dim out of range" << std::endl; return; }
+            int n = (int)fu->latt[dim];
+            int newval;
+            if (!valstr.empty() && (valstr[0] == '+' || valstr[0] == '-')) {
+                int delta = std::stoi(valstr);
+                newval = ((fu->Slice[dim] + delta) % n + n) % n;
+            } else {
+                newval = ((std::stoi(valstr) % n) + n) % n;
+            }
+            fu->Slice[dim] = newval;
+            fu->ForceRender(iren);
+            PrintStatus();
+        }
+
+        // ── zoom <factor> ────────────────────────────────────────────────────
+        else if (verb == "zoom") {
+            double factor;
+            if (!(iss >> factor)) { std::cout << "[cmd] zoom: expected factor" << std::endl; return; }
+            camera->Dolly(factor);
+            renderer->ResetCameraClippingRange();
+            iren->GetRenderWindow()->Render();
+        }
+
+        // ── azimuth <degrees> ────────────────────────────────────────────────
+        else if (verb == "azimuth") {
+            double deg;
+            if (!(iss >> deg)) { std::cout << "[cmd] azimuth: expected degrees" << std::endl; return; }
+            camera->Azimuth(deg);
+            renderer->ResetCameraClippingRange();
+            iren->GetRenderWindow()->Render();
+        }
+
+        // ── elevation <degrees> ──────────────────────────────────────────────
+        else if (verb == "elevation") {
+            double deg;
+            if (!(iss >> deg)) { std::cout << "[cmd] elevation: expected degrees" << std::endl; return; }
+            camera->Elevation(deg);
+            renderer->ResetCameraClippingRange();
+            iren->GetRenderWindow()->Render();
+        }
+
+        // ── spin <degrees_per_tick> ──────────────────────────────────────────
+        // Applies azimuth rotation on every 100ms poll tick. spin 0 stops.
+        else if (verb == "spin") {
+            double deg;
+            if (!(iss >> deg)) { std::cout << "[cmd] spin: expected degrees" << std::endl; return; }
+            g_spinDeg = deg;
+            std::cout << "[cmd] spin rate = " << g_spinDeg << " deg/tick" << std::endl;
+        }
+
+        // ── caption user: <text> / caption claude: <text> / caption ─────────
+        // user:   clears both lines, types user text (gold) on upper line.
+        // claude: keeps user line, types response (light blue) on lower line.
+        // caption alone clears both immediately.
+        else if (verb == "caption") {
+            std::string rest;
+            std::getline(iss, rest);
+            if (!rest.empty() && rest[0] == ' ') rest = rest.substr(1);
+            if (rest.empty()) {
+                g_userCaptionFull = ""; g_userCaptionPos = 0;
+                g_claudeCaptionFull = ""; g_claudeCaptionPos = 0;
+                g_captionTick = 0;
+                if (userCaptionActor) userCaptionActor->SetInput("");
+                if (captionActor)     captionActor->SetInput("");
+                iren->GetRenderWindow()->Render(); CaptureFrame();
+            } else if (rest.substr(0,5) == "user:") {
+                // New instruction: clear both, start typing user text
+                g_claudeCaptionFull = ""; g_claudeCaptionPos = 0;
+                g_userCaptionFull = WrapText(rest); g_userCaptionPos = 0;
+                g_captionTick = 0;
+                if (userCaptionActor) userCaptionActor->SetInput("");
+                if (captionActor)     captionActor->SetInput("");
+                iren->GetRenderWindow()->Render(); CaptureFrame();
+            } else {
+                // claude: or unlabelled — keep user line, type below
+                g_claudeCaptionFull = WrapText(rest); g_claudeCaptionPos = 0;
+                g_captionTick = 0;
+            }
+        }
+
+        // ── record start <filename> / record stop ────────────────────────────
+        else if (verb == "record") {
+#ifdef MPEG
+            std::string sub;
+            if (!(iss >> sub)) { std::cout << "[cmd] record: expected start <file> or stop" << std::endl; return; }
+            if (sub == "stop") {
+                if (g_recording && g_mpegWriter) {
+                    g_mpegWriter->End();
+                    g_mpegWriter->Delete(); g_mpegWriter = nullptr;
+                    g_imageFilter->Delete(); g_imageFilter = nullptr;
+                    g_recording = false;
+                    std::cout << "[cmd] recording stopped: " << g_recordingFile << std::endl;
+                    // Write WAV and mux to MP4
+                    std::string wavFile = g_recordingFile + ".wav";
+                    WriteWAV(wavFile, g_audioBuffer, AUDIO_RATE);
+                    g_audioBuffer.clear();
+                    std::string mp4File = g_recordingFile;
+                    if (mp4File.size() > 4 && mp4File.substr(mp4File.size()-4) == ".avi")
+                        mp4File = mp4File.substr(0, mp4File.size()-4) + ".mp4";
+                    else
+                        mp4File += ".mp4";
+                    std::string cmd = "ffmpeg -y -i \"" + g_recordingFile + "\" -i \"" + wavFile +
+                                      "\" -c:v copy -c:a aac -shortest \"" + mp4File + "\" 2>/dev/null";
+                    int ret = system(cmd.c_str());
+                    if (ret == 0) {
+                        std::cout << "[cmd] muxed output: " << mp4File << std::endl;
+                        unlink(wavFile.c_str());  // clean up intermediate WAV
+                    } else {
+                        std::cout << "[cmd] mux failed (ffmpeg not found?). WAV kept: " << wavFile << std::endl;
+                    }
+                } else {
+                    std::cout << "[cmd] not recording" << std::endl;
+                }
+            } else if (sub == "start") {
+                std::string fname = "recording.avi";
+                iss >> fname;
+                if (g_recording) { std::cout << "[cmd] already recording" << std::endl; return; }
+                g_recordingFile    = fname;
+                g_audioBuffer.clear();
+                g_samplesPerFrame  = AUDIO_RATE / std::max(1, g_framerate);
+                g_beepRemaining    = 0;
+                g_beepPhase        = 0.0;
+                g_imageFilter = vtkWindowToImageFilter::New();
+                g_imageFilter->SetInput(iren->GetRenderWindow());
+                g_imageFilter->SetInputBufferTypeToRGB();
+                g_mpegWriter = vtkFFMPEGWriter::New();
+                g_mpegWriter->SetFileName(fname.c_str());
+                g_mpegWriter->SetRate(g_framerate);
+                g_mpegWriter->SetInputConnection(g_imageFilter->GetOutputPort());
+                g_mpegWriter->Start();
+                g_recording = true;
+                std::cout << "[cmd] recording started: " << fname << std::endl;
+            } else {
+                std::cout << "[cmd] record: unknown subcommand '" << sub << "'" << std::endl;
+            }
+#else
+            std::cout << "[cmd] record: MPEG support not compiled" << std::endl;
+#endif
+        }
+
+        // ── iso <value> ──────────────────────────────────────────────────────
+        else if (verb == "iso") {
+            double val;
+            if (!(iss >> val)) { std::cout << "[cmd] iso: expected value" << std::endl; return; }
+            SetIsosurface(val);
+            fu->ForceRender(iren);
+            PrintStatus();
+        }
+
+        // ── file <index|+N|-N> ───────────────────────────────────────────────
+        else if (verb == "file") {
+            std::string valstr;
+            if (!(iss >> valstr)) { std::cout << "[cmd] file: expected index" << std::endl; return; }
+            int n = (int)fu->files.size();
+            int newval;
+            if (!valstr.empty() && (valstr[0] == '+' || valstr[0] == '-')) {
+                int delta = std::stoi(valstr);
+                newval = ((fu->ffile + delta) % n + n) % n;
+            } else {
+                newval = ((std::stoi(valstr) % n) + n) % n;
+            }
+            fu->ffile    = newval;
+            fu->old_file = -1;
+            fu->ForceRender(iren);
+            PrintStatus();
+        }
+
+        // ── render ───────────────────────────────────────────────────────────
+        else if (verb == "render") {
+            fu->ForceRender(iren);
+        }
+
+        // ── status ───────────────────────────────────────────────────────────
+        else if (verb == "status") {
+            PrintStatus();
+        }
+
+        // ── quit ─────────────────────────────────────────────────────────────
+        else if (verb == "quit" || verb == "exit") {
+            g_running = false;
+            iren->TerminateApp();
+        }
+
+        else {
+            std::cout << "[cmd] Unknown command: '" << line << "'" << std::endl;
+        }
+    }
+
+    virtual void Execute(vtkObject*, unsigned long eventId, void* callData)
+    {
+        if (eventId != vtkCommand::TimerEvent) return;
+        if (pollTimerId >= 0) {
+            int tid = *(reinterpret_cast<int*>(callData));
+            if (tid != pollTimerId) return;
+        }
+
+        std::vector<std::string> pending;
+        {
+            std::lock_guard<std::mutex> lk(g_cmdMutex);
+            while (!g_cmdQueue.empty()) { pending.push_back(g_cmdQueue.front()); g_cmdQueue.pop(); }
+        }
+        for (const auto& line : pending) {
+            std::cout << "[cmd] >> " << line << std::endl;
+            RunLine(line);
+            // CaptureFrame() called inside RunLine for caption; for other
+            // rendering commands capture here (duplicate Modified() is harmless)
+            CaptureFrame();
+        }
+
+        // Typewriter: advance one character every g_captionRate ticks.
+        // User line types first; claude line starts once user line is complete.
+        bool typing = (g_userCaptionPos < g_userCaptionFull.size()) ||
+                      (g_claudeCaptionPos < g_claudeCaptionFull.size());
+        if (typing) {
+            if (++g_captionTick >= g_captionRate) {
+                g_captionTick = 0;
+                bool rendered = false;
+                if (g_userCaptionPos < g_userCaptionFull.size()) {
+                    ++g_userCaptionPos;
+                    if (userCaptionActor)
+                        userCaptionActor->SetInput(g_userCaptionFull.substr(0, g_userCaptionPos).c_str());
+                    PlayBeepAudible();
+                    TriggerBeep();
+                    rendered = true;
+                } else if (g_claudeCaptionPos < g_claudeCaptionFull.size()) {
+                    ++g_claudeCaptionPos;
+                    if (captionActor)
+                        captionActor->SetInput(g_claudeCaptionFull.substr(0, g_claudeCaptionPos).c_str());
+                    rendered = true;
+                }
+                if (rendered) {
+                    iren->GetRenderWindow()->Render();
+                    CaptureFrame();
+                }
+            }
+        }
+
+        // Apply continuous spin (if active) at poll-timer rate
+        if (g_spinDeg != 0.0) {
+            camera->Azimuth(g_spinDeg);
+            renderer->ResetCameraClippingRange();
+            iren->GetRenderWindow()->Render();
+            CaptureFrame();
+        }
+    }
+};
+
+// ─── main ─────────────────────────────────────────────────────────────────────
+int main(int argc, char* argv[])
+{
+    using namespace Grid;
+
+    Grid_init(&argc, &argv);
+    GridLogLayout();
+
+    auto latt_size   = GridDefaultLatt();
+    auto simd_layout = GridDefaultSimd(latt_size.size(), vComplex::Nsimd());
+    auto mpi_layout  = GridDefaultMpi();
+    GridCartesian Grid(latt_size, simd_layout, mpi_layout);
+
+    double default_contour = 1.0;
+    std::string arg;
+
+    std::vector<std::string> file_list({"file1","file2","file3","file4",
+                                        "file5","file6","file7","file8"});
+
+    if (GridCmdOptionExists(argv, argv+argc, "--files")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--files");
+        GridCmdOptionCSL(arg, file_list);
+    }
+#ifdef MPEG
+    if (GridCmdOptionExists(argv, argv+argc, "--mpeg")) g_mpeg = 1;
+#endif
+    if (GridCmdOptionExists(argv, argv+argc, "--fps")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--fps");
+        GridCmdOptionInt(arg, g_framerate);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--isosurface")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--isosurface");
+        GridCmdOptionFloat(arg, default_contour);
+    }
+
+    int NoTime = 0, Nd = Grid.Nd();
+    Coordinate Slice(Nd,0), SumDims(Nd,0), LoopDims(Nd,0), XYZDims({0,1,2});
+
+    if (GridCmdOptionExists(argv, argv+argc, "--slice")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--slice");
+        GridCmdOptionIntVector(arg, Slice);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--sum")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--sum");
+        GridCmdOptionIntVector(arg, SumDims);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--loop")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--loop");
+        GridCmdOptionIntVector(arg, LoopDims);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--xyz")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--xyz");
+        GridCmdOptionIntVector(arg, XYZDims);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--notime")) { NoTime = 1; }
+
+    std::thread cmdThread(CommandReaderThread);
+    cmdThread.detach();
+
+    // ── VTK scene ────────────────────────────────────────────────────────────
+    vtkNew<vtkNamedColors> colors;
+    std::array<unsigned char,4> posColor{{240,184,160,255}}; colors->SetColor("posColor", posColor.data());
+    std::array<unsigned char,4> bkg{{51,77,102,255}};        colors->SetColor("BkgColor", bkg.data());
+
+    vtkNew<vtkRenderWindow>           renWin;
+    vtkNew<vtkRenderWindowInteractor> iren;
+    iren->SetRenderWindow(renWin);
+
+    int frameCount = (int)file_list.size();
+    for (int d = 0; d < Nd; d++) if (LoopDims[d]) frameCount *= latt_size[d];
+
+    vtkNew<vtkCamera> aCamera;
+    aCamera->SetViewUp(0,0,-1); aCamera->SetPosition(0,-1000,0); aCamera->SetFocalPoint(0,0,0);
+    aCamera->ComputeViewPlaneNormal(); aCamera->Azimuth(30.0); aCamera->Elevation(30.0);
+
+    vtkNew<vtkRenderer> aRenderer;
+    renWin->AddRenderer(aRenderer);
+
+    double nrm, rms, contour;
+    { LatticeComplexD data(&Grid); readFile(data, file_list[0]); nrm = norm2(data); }
+    rms     = std::sqrt(nrm / Grid.gSites());
+    contour = default_contour * rms;
+
+    vtkNew<vtkImageData> imageData;
+    imageData->SetDimensions(latt_size[XYZDims[0]], latt_size[XYZDims[1]], latt_size[XYZDims[2]]);
+    imageData->AllocateScalars(VTK_DOUBLE, 1);
+    for (int xx=0;xx<latt_size[XYZDims[0]];xx++)
+    for (int yy=0;yy<latt_size[XYZDims[1]];yy++)
+    for (int zz=0;zz<latt_size[XYZDims[2]];zz++)
+        imageData->SetScalarComponentFromDouble(xx,yy,zz,0,0.0);
+
+    vtkNew<isosurface> posExtractor; posExtractor->SetInputData(imageData); posExtractor->SetValue(0,  contour);
+    vtkNew<vtkStripper> posStripper; posStripper->SetInputConnection(posExtractor->GetOutputPort());
+    vtkNew<vtkPolyDataMapper> posMapper; posMapper->SetInputConnection(posStripper->GetOutputPort()); posMapper->ScalarVisibilityOff();
+    vtkNew<vtkActor> pos; pos->SetMapper(posMapper);
+    pos->GetProperty()->SetDiffuseColor(colors->GetColor3d("posColor").GetData());
+    pos->GetProperty()->SetSpecular(0.3); pos->GetProperty()->SetSpecularPower(20); pos->GetProperty()->SetOpacity(0.5);
+
+    vtkNew<isosurface> negExtractor; negExtractor->SetInputData(imageData); negExtractor->SetValue(0, -contour);
+    vtkNew<vtkStripper> negStripper; negStripper->SetInputConnection(negExtractor->GetOutputPort());
+    vtkNew<vtkPolyDataMapper> negMapper; negMapper->SetInputConnection(negStripper->GetOutputPort()); negMapper->ScalarVisibilityOff();
+    vtkNew<vtkActor> neg; neg->SetMapper(negMapper);
+    neg->GetProperty()->SetDiffuseColor(colors->GetColor3d("Ivory").GetData());
+
+    vtkNew<vtkOutlineFilter> outlineData; outlineData->SetInputData(imageData);
+    vtkNew<vtkPolyDataMapper> mapOutline; mapOutline->SetInputConnection(outlineData->GetOutputPort());
+    vtkNew<vtkActor> outline; outline->SetMapper(mapOutline);
+    outline->GetProperty()->SetColor(colors->GetColor3d("Black").GetData());
+
+    vtkNew<vtkTextActor> TextT;
+    TextT->SetInput("Initialising...");
+    TextT->SetPosition(10, 920);
+    TextT->GetTextProperty()->SetFontSize(24);
+    TextT->GetTextProperty()->SetColor(colors->GetColor3d("Gold").GetData());
+
+    // Claude response caption (light blue, lower line)
+    vtkNew<vtkTextActor> CaptionT;
+    CaptionT->SetInput("");
+    CaptionT->SetPosition(512, 38);
+    CaptionT->GetTextProperty()->SetFontSize(32);
+    CaptionT->GetTextProperty()->SetColor(0.6, 0.9, 1.0);
+    CaptionT->GetTextProperty()->SetJustificationToCentered();
+    CaptionT->GetTextProperty()->SetBackgroundColor(0.0, 0.0, 0.0);
+    CaptionT->GetTextProperty()->SetBackgroundOpacity(0.6);
+    CaptionT->GetTextProperty()->BoldOn();
+
+    // User instruction caption (gold, upper line)
+    vtkNew<vtkTextActor> UserCaptionT;
+    UserCaptionT->SetInput("");
+    UserCaptionT->SetPosition(512, 82);
+    UserCaptionT->GetTextProperty()->SetFontSize(32);
+    UserCaptionT->GetTextProperty()->SetColor(1.0, 0.85, 0.0);
+    UserCaptionT->GetTextProperty()->SetJustificationToCentered();
+    UserCaptionT->GetTextProperty()->SetBackgroundColor(0.0, 0.0, 0.0);
+    UserCaptionT->GetTextProperty()->SetBackgroundOpacity(0.6);
+    UserCaptionT->GetTextProperty()->BoldOn();
+
+    aRenderer->AddActor(TextT); aRenderer->AddActor(CaptionT); aRenderer->AddActor(UserCaptionT); aRenderer->AddActor(outline);
+    aRenderer->AddActor(pos);   aRenderer->AddActor(neg);
+
+    vtkNew<FrameUpdater> fu;
+    fu->SetGrid(&Grid); fu->SetFiles(file_list); fu->SetSlice(Slice);
+    fu->SetSumDimensions(SumDims); fu->SetLoopDimensions(LoopDims);
+    fu->SetDisplayDimensions(XYZDims); fu->SetSliceDimensions();
+    fu->imageData = imageData; fu->text = TextT; fu->maxCount = frameCount;
+    fu->posExtractor = posExtractor; fu->negExtractor = negExtractor; fu->rms = rms;
+
+    iren->AddObserver(vtkCommand::TimerEvent,    fu);
+    iren->AddObserver(vtkCommand::KeyPressEvent, fu);
+
+    aRenderer->SetActiveCamera(aCamera); aRenderer->ResetCamera();
+    aRenderer->SetBackground(colors->GetColor3d("BkgColor").GetData());
+    aCamera->Dolly(1.0); aRenderer->SetViewport(0.0,0.0,1.0,1.0);
+    aRenderer->ResetCameraClippingRange();
+    renWin->SetSize(1024,1024); renWin->SetWindowName("ControlledFieldDensity");
+    renWin->Render(); iren->Initialize();
+
+    // CommandHandler on fast poll timer
+    vtkNew<CommandHandler> cmdHandler;
+    cmdHandler->fu             = fu;
+    cmdHandler->camera         = aCamera;
+    cmdHandler->renderer       = aRenderer;
+    cmdHandler->iren           = iren;
+    cmdHandler->captionActor     = CaptionT;
+    cmdHandler->userCaptionActor = UserCaptionT;
+    cmdHandler->isosurfaceLevel = default_contour;
+    iren->AddObserver(vtkCommand::TimerEvent, cmdHandler);
+    cmdHandler->pollTimerId = iren->CreateRepeatingTimer(100);
+
+    if (g_mpeg == 0 && NoTime == 0) {
+        fu->timerId = iren->CreateRepeatingTimer(10000 / g_framerate);
+    }
+
+    if (g_mpeg) {
+#ifdef MPEG
+        vtkWindowToImageFilter* imageFilter = vtkWindowToImageFilter::New();
+        imageFilter->SetInput(renWin); imageFilter->SetInputBufferTypeToRGB();
+        vtkFFMPEGWriter* writer = vtkFFMPEGWriter::New();
+        writer->SetFileName("movie.avi"); writer->SetRate(g_framerate);
+        writer->SetInputConnection(imageFilter->GetOutputPort()); writer->Start();
+        for (int i = 0; i < fu->maxCount; i++) {
+            fu->Execute(iren, vtkCommand::TimerEvent, &fu->timerId);
+            imageFilter->Modified(); writer->Write();
+        }
+        writer->End(); writer->Delete(); imageFilter->Delete();
+#else
+        assert(-1 && "MPEG support not compiled");
+#endif
+    } else {
+        iren->Start();
+    }
+
+    g_running = false;
+    Grid_finalize();
+    return EXIT_SUCCESS;
+}

visualisation/ForceAnalysis.cxx

@@ -0,0 +1,633 @@
+// ForceAnalysis.cxx
+//
+// Reads a sequence of force snapshot files (LatticeComplexD, real part = force magnitude)
+// and produces two outputs:
+//
+//   1. Tab-separated timeseries to stdout:
+//        idx  Gauge_lat_rms  Gauge_lat_hot  Gauge_smr_rms  ...
+//      where _rms is the lattice RMS and _hot is the value at --hotsite.
+//
+//   2. PNG images (one per force component per snapshot) rendered via VTK
+//      as isosurfaces of the force density, using the same pipeline as
+//      Visualise5D.  Images are written to --pngdir/<label>_<idx>.png.
+//      These can be read back by Claude to interpret spatial structure.
+//
+// Usage:
+//   ForceAnalysis --grid 32.32.32.32 --mpi 1.1.1.1
+//                 --snapdir /path/to/snapshots
+//                 --first 0 --last 1920 --step 10
+//                 --hotsite x.y.z.t
+//                 --pngdir /path/to/output/pngs
+//                 --isosurface 1.0        (contour in units of field RMS)
+//                 --fixediso 0.05         (fixed absolute contour, overrides --isosurface)
+//                 --slice t               (which dimension to fix for 3D display, default: t)
+//                 --sliceval 2            (value of that dimension, default: 0)
+//
+// Dimension order on the 32^4 lattice: x=0 y=1 z=2 t=3
+
+#include <vtkActor.h>
+#include <vtkActor2D.h>
+#include <vtkCamera.h>
+#include <vtkImageActor.h>
+#include <vtkImageMapper3D.h>
+#include <vtkImageData.h>
+#include <vtkImageMapToColors.h>
+#include <vtkLookupTable.h>
+#include <vtkNamedColors.h>
+#include <vtkNew.h>
+#include <vtkOutlineFilter.h>
+#include <vtkPolyData.h>
+#include <vtkPolyDataMapper.h>
+#include <vtkPolyDataMapper2D.h>
+#include <vtkProperty.h>
+#include <vtkProperty2D.h>
+#include <vtkPoints.h>
+#include <vtkCellArray.h>
+#include <vtkRenderWindow.h>
+#include <vtkRenderWindowInteractor.h>
+#include <vtkRenderer.h>
+#include <vtkStripper.h>
+#include <vtkCallbackCommand.h>
+#include <vtkTextActor.h>
+#include <vtkTextProperty.h>
+#include <vtkWindowToImageFilter.h>
+#include <vtkPNGWriter.h>
+
+#define USE_FLYING_EDGES
+#ifdef USE_FLYING_EDGES
+#include <vtkFlyingEdges3D.h>
+typedef vtkFlyingEdges3D isosurface;
+#else
+#include <vtkMarchingCubes.h>
+typedef vtkMarchingCubes isosurface;
+#endif
+
+#include <Grid/Grid.h>
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <iomanip>
+#include <string>
+#include <vector>
+#include <cmath>
+#include <memory>
+#include <sys/stat.h>
+
+using namespace Grid;
+
+// ─── I/O ─────────────────────────────────────────────────────────────────────
+template <class T>
+bool tryReadFile(T& out, const std::string& fname)
+{
+    std::ifstream test(fname);
+    if (!test.good()) return false;
+    test.close();
+    emptyUserRecord record;
+    ScidacReader RD;
+    RD.open(fname);
+    RD.readScidacFieldRecord(out, record);
+    RD.close();
+    return true;
+}
+
+// ─── Fill a 3D vtkImageData slice from a 4D lattice field ────────────────────
+// Sums over the sliced dimension at sliceval, displays the remaining 3 dims.
+void fillImageData(vtkImageData* img,
+                   LatticeComplexD& field,
+                   const Coordinate& latt_size,
+                   int slice_dim, int sliceval)
+{
+    // Display dims = all dims except slice_dim, in order
+    std::vector<int> disp;
+    for (int d = 0; d < 4; d++) if (d != slice_dim) disp.push_back(d);
+
+    int Nx = latt_size[disp[0]];
+    int Ny = latt_size[disp[1]];
+    int Nz = latt_size[disp[2]];
+
+    for (int ix = 0; ix < Nx; ix++)
+    for (int iy = 0; iy < Ny; iy++)
+    for (int iz = 0; iz < Nz; iz++) {
+        Coordinate site(4);
+        site[disp[0]]  = ix;
+        site[disp[1]]  = iy;
+        site[disp[2]]  = iz;
+        site[slice_dim] = sliceval;
+        RealD val = real(peekSite(field, site));
+        img->SetScalarComponentFromDouble(ix, iy, iz, 0, val);
+    }
+    img->Modified();
+}
+
+// ─── 2D heatmap: persistent context ───────────────────────────────────────────
+// Renders a fixed (dim1=v1, dim2=v2) slice of the 4D force field as a
+// diverging blue→white→red colour map, with a fixed symmetric colour scale
+// so brightness directly encodes force magnitude across all frames.
+// A white cross-hair marks the hotsite projection onto the slice.
+struct HeatmapCtx {
+    // image pipeline
+    vtkNew<vtkImageData>         img;
+    vtkNew<vtkLookupTable>       lut;
+    vtkNew<vtkImageMapToColors>  colorMap;
+    vtkNew<vtkImageActor>        imgActor;
+    // colour scale legend (text, avoids needing RenderingAnnotation module)
+    vtkNew<vtkTextActor>         cbar;
+    // hotsite cross-hair (2D overlay actors)
+    vtkNew<vtkPolyData>          crossPD;
+    vtkNew<vtkPoints>            crossPts;
+    vtkNew<vtkCellArray>         crossLines;
+    vtkNew<vtkActor2D>           crossActor;
+    // title
+    vtkNew<vtkTextActor>         titleAct;
+    // renderer / window
+    vtkNew<vtkRenderer>          ren;
+    vtkNew<vtkRenderWindow>      renWin;
+    vtkNew<vtkWindowToImageFilter> w2i;
+    vtkNew<vtkPNGWriter>         writer;
+
+    int Nx = 0, Ny = 0;           // display dimensions of the slice
+    double scale = 0.07;          // colour range: [-scale, +scale]
+    int hotX = -1, hotY = -1;     // hotsite projection onto (Nx,Ny) plane
+    // pixel coords of the image origin in the render window
+    int imgOffX = 60, imgOffY = 40;
+    int imgW = 0, imgH = 0;       // rendered pixel size of each lattice cell
+
+    void init(int nx, int ny, double sc, int hx, int hy)
+    {
+        Nx = nx; Ny = ny; scale = sc;
+        hotX = hx; hotY = hy;
+
+        const int WIN_W = 900, WIN_H = 700;
+        // Make cells square and as large as possible within the central area
+        int cellW = (WIN_W - 160) / Nx;
+        int cellH = (WIN_H - 120) / Ny;
+        imgW = std::min(cellW, cellH);
+        imgH = imgW;
+        imgOffX = (WIN_W - Nx * imgW) / 2;
+        imgOffY = 60;
+
+        // --- Image data (scalar field, one component) ---
+        img->SetDimensions(Nx, Ny, 1);
+        img->SetSpacing(imgW, imgH, 1);
+        img->SetOrigin(imgOffX, imgOffY, 0);
+        img->AllocateScalars(VTK_DOUBLE, 1);
+
+        // --- Diverging LUT: blue(-scale) → white(0) → red(+scale) ---
+        lut->SetNumberOfTableValues(512);
+        lut->SetRange(-scale, scale);
+        lut->SetNanColor(0.2, 0.2, 0.2, 1.0);
+        for (int i = 0; i < 512; ++i) {
+            double t = i / 511.0;   // 0=blue, 0.5=white, 1=red
+            double r = (t > 0.5) ? 1.0 : 2.0 * t;
+            double g = (t < 0.5) ? 2.0 * t : 2.0 * (1.0 - t);
+            double b = (t < 0.5) ? 1.0 : 2.0 * (1.0 - t);
+            lut->SetTableValue(i, r, g, b, 1.0);
+        }
+        lut->Build();
+
+        // --- Colour map pipeline ---
+        colorMap->SetInputData(img);
+        colorMap->SetLookupTable(lut);
+        colorMap->Update();
+
+        imgActor->GetMapper()->SetInputConnection(colorMap->GetOutputPort());
+
+        // --- Colour scale legend (text) ---
+        {
+            std::ostringstream ss;
+            ss << std::scientific << std::setprecision(2)
+               << "blue=-" << sc << "  white=0  red=+" << sc;
+            cbar->SetInput(ss.str().c_str());
+        }
+        cbar->GetTextProperty()->SetFontFamilyToCourier();
+        cbar->GetTextProperty()->SetFontSize(13);
+        cbar->GetTextProperty()->SetColor(0.9, 0.9, 0.9);
+        cbar->SetDisplayPosition(10, 10);
+
+        // --- Cross-hair at hotsite (2D display coords) ---
+        if (hotX >= 0 && hotY >= 0) {
+            double cx = imgOffX + (hotX + 0.5) * imgW;
+            double cy = imgOffY + (hotY + 0.5) * imgH;
+            double arm = imgW * 0.8;
+            crossPts->InsertNextPoint(cx - arm, cy, 0);
+            crossPts->InsertNextPoint(cx + arm, cy, 0);
+            crossPts->InsertNextPoint(cx, cy - arm, 0);
+            crossPts->InsertNextPoint(cx, cy + arm, 0);
+            vtkIdType seg0[2] = {0, 1};
+            vtkIdType seg1[2] = {2, 3};
+            crossLines->InsertNextCell(2, seg0);
+            crossLines->InsertNextCell(2, seg1);
+            crossPD->SetPoints(crossPts);
+            crossPD->SetLines(crossLines);
+            vtkNew<vtkPolyDataMapper2D> crossMap;
+            crossMap->SetInputData(crossPD);
+            crossActor->SetMapper(crossMap);
+            crossActor->GetProperty()->SetColor(1, 1, 1);
+            crossActor->GetProperty()->SetLineWidth(2.0);
+        }
+
+        // --- Title ---
+        titleAct->GetTextProperty()->SetFontFamilyToCourier();
+        titleAct->GetTextProperty()->SetFontSize(16);
+        titleAct->GetTextProperty()->SetColor(1, 1, 0);
+        titleAct->SetDisplayPosition(10, WIN_H - 30);
+
+        // --- Renderer (2D parallel projection so image fills correctly) ---
+        ren->SetBackground(0.08, 0.08, 0.12);
+        ren->AddActor(imgActor);
+        ren->AddActor2D(cbar);
+        ren->AddActor2D(crossActor);
+        ren->AddActor2D(titleAct);
+        ren->GetActiveCamera()->ParallelProjectionOn();
+        // Set up camera to look straight down at the image plane
+        ren->GetActiveCamera()->SetPosition(WIN_W/2.0, WIN_H/2.0, 1000);
+        ren->GetActiveCamera()->SetFocalPoint(WIN_W/2.0, WIN_H/2.0, 0);
+        ren->GetActiveCamera()->SetViewUp(0, 1, 0);
+        ren->GetActiveCamera()->SetParallelScale(WIN_H / 2.0);
+        ren->ResetCameraClippingRange();
+
+        renWin->AddRenderer(ren);
+        renWin->SetSize(WIN_W, WIN_H);
+        renWin->SetOffScreenRendering(1);
+        renWin->SetMultiSamples(0);
+
+        w2i->SetInput(renWin);
+        w2i->SetInputBufferTypeToRGB();
+        w2i->ReadFrontBufferOff();
+    }
+};
+
+void renderHeatmap(HeatmapCtx& ctx,
+                   LatticeComplexD& field,
+                   const Coordinate& latt_size,
+                   int dim1, int val1,   // first fixed dimension
+                   int dim2, int val2,   // second fixed dimension
+                   const std::string& title,
+                   const std::string& outpath)
+{
+    // Display dimensions: the two dims that are NOT fixed
+    std::vector<int> disp;
+    for (int d = 0; d < 4; d++)
+        if (d != dim1 && d != dim2) disp.push_back(d);
+
+    int Nx = latt_size[disp[0]];
+    int Ny = latt_size[disp[1]];
+
+    // Fill image data
+    for (int ix = 0; ix < Nx; ix++) {
+        for (int iy = 0; iy < Ny; iy++) {
+            Coordinate site(4);
+            site[disp[0]] = ix;
+            site[disp[1]] = iy;
+            site[dim1]    = val1;
+            site[dim2]    = val2;
+            RealD val = real(TensorRemove(peekSite(field, site)));
+            ctx.img->SetScalarComponentFromDouble(ix, iy, 0, 0, val);
+        }
+    }
+    ctx.img->Modified();
+    ctx.colorMap->Update();
+
+    ctx.titleAct->SetInput(title.c_str());
+
+    ctx.renWin->Render();
+    ctx.w2i->Modified();
+    ctx.w2i->Update();
+
+    ctx.writer->SetFileName(outpath.c_str());
+    ctx.writer->SetInputConnection(ctx.w2i->GetOutputPort());
+    ctx.writer->Write();
+}
+
+// ─── Persistent rendering context (created once, reused every frame) ──────────
+// Avoids Metal GPU context exhaustion on macOS when rendering hundreds of frames.
+struct RenderCtx {
+    vtkNew<vtkNamedColors>       colors;
+    vtkNew<vtkImageData>         imageData;
+    vtkNew<isosurface>           posEx, negEx;
+    vtkNew<vtkStripper>          posSt, negSt;
+    vtkNew<vtkPolyDataMapper>    posMap, negMap, outMap;
+    vtkNew<vtkActor>             posAct, negAct, outAct;
+    vtkNew<vtkOutlineFilter>     outF;
+    vtkNew<vtkTextActor>         label;
+    vtkNew<vtkRenderer>          ren;
+    vtkNew<vtkCamera>            cam;
+    vtkNew<vtkRenderWindow>      renWin;
+    vtkNew<vtkWindowToImageFilter> w2i;
+    vtkNew<vtkPNGWriter>         writer;
+
+    void init(int Nx, int Ny, int Nz)
+    {
+        std::array<unsigned char,4> posColor{{240,184,160,255}};
+        colors->SetColor("posColor", posColor.data());
+        std::array<unsigned char,4> bkg{{51,77,102,255}};
+        colors->SetColor("BkgColor", bkg.data());
+
+        imageData->SetDimensions(Nx, Ny, Nz);
+        imageData->AllocateScalars(VTK_DOUBLE, 1);
+
+        posEx->SetInputData(imageData); posEx->SetValue(0,  1.0);
+        posSt->SetInputConnection(posEx->GetOutputPort());
+        posMap->SetInputConnection(posSt->GetOutputPort());
+        posMap->ScalarVisibilityOff();
+        posAct->SetMapper(posMap);
+        posAct->GetProperty()->SetDiffuseColor(colors->GetColor3d("posColor").GetData());
+        posAct->GetProperty()->SetSpecular(0.3);
+        posAct->GetProperty()->SetSpecularPower(20);
+        posAct->GetProperty()->SetOpacity(0.6);
+
+        negEx->SetInputData(imageData); negEx->SetValue(0, -1.0);
+        negSt->SetInputConnection(negEx->GetOutputPort());
+        negMap->SetInputConnection(negSt->GetOutputPort());
+        negMap->ScalarVisibilityOff();
+        negAct->SetMapper(negMap);
+        negAct->GetProperty()->SetDiffuseColor(colors->GetColor3d("Ivory").GetData());
+        negAct->GetProperty()->SetOpacity(0.6);
+
+        outF->SetInputData(imageData);
+        outMap->SetInputConnection(outF->GetOutputPort());
+        outAct->SetMapper(outMap);
+        outAct->GetProperty()->SetColor(colors->GetColor3d("Black").GetData());
+
+        label->SetPosition(10, 10);
+        label->GetTextProperty()->SetFontFamilyToCourier();
+        label->GetTextProperty()->SetFontSize(18);
+        label->GetTextProperty()->SetColor(colors->GetColor3d("Gold").GetData());
+
+        ren->AddActor(posAct);
+        ren->AddActor(negAct);
+        ren->AddActor(outAct);
+        ren->AddActor2D(label);
+        ren->SetBackground(colors->GetColor3d("BkgColor").GetData());
+
+        cam->SetViewUp(0,0,-1);
+        cam->SetPosition(0,-1000,0);
+        cam->SetFocalPoint(0,0,0);
+        cam->ComputeViewPlaneNormal();
+        cam->Azimuth(30.0);
+        cam->Elevation(30.0);
+        ren->SetActiveCamera(cam);
+
+        renWin->AddRenderer(ren);
+        renWin->SetSize(800, 600);
+        renWin->SetOffScreenRendering(1);
+        renWin->SetMultiSamples(0);
+
+        w2i->SetInput(renWin);
+        w2i->SetInputBufferTypeToRGB();
+        w2i->ReadFrontBufferOff();
+    }
+};
+
+// ─── Render one force field snapshot to a PNG (reuses existing RenderCtx) ─────
+void renderPNG(RenderCtx& ctx,
+               LatticeComplexD& field,
+               const Coordinate& latt_size,
+               int slice_dim, int sliceval,
+               double contour,
+               const std::string& title,
+               const std::string& outpath)
+{
+    // Update image data
+    fillImageData(ctx.imageData, field, latt_size, slice_dim, sliceval);
+
+    // Update isosurface levels
+    ctx.posEx->SetValue(0,  contour);
+    ctx.negEx->SetValue(0, -contour);
+
+    // Update label
+    ctx.label->SetInput(title.c_str());
+
+    // Reset camera to fit the (possibly new) data bounds
+    ctx.ren->ResetCamera();
+    ctx.cam->Dolly(1.2);
+    ctx.ren->ResetCameraClippingRange();
+
+    ctx.renWin->Render();
+
+    ctx.w2i->Modified();
+    ctx.w2i->Update();
+
+    ctx.writer->SetFileName(outpath.c_str());
+    ctx.writer->SetInputConnection(ctx.w2i->GetOutputPort());
+    ctx.writer->Write();
+}
+
+// ─── main ─────────────────────────────────────────────────────────────────────
+int main(int argc, char* argv[])
+{
+    Grid_init(&argc, &argv);
+    GridLogMessage.Active(0);
+    GridLogIterative.Active(0);
+    GridLogDebug.Active(0);
+    GridLogPerformance.Active(0);
+    GridLogComms.Active(0);
+    GridLogDslash.Active(0);
+    GridLogMemory.Active(0);
+
+    // ── CLI ──────────────────────────────────────────────────────────────────
+    std::string snapdir = ".";
+    std::string pngdir  = "";
+    int first = 0, last = 1920, step = 1;
+    int slice_dim = 3, sliceval = 0;   // default: fix t=0, display xyz
+    double iso_rms    = 1.0;
+    double fixed_iso  = -1.0;   // if >0, use this absolute contour
+    double tau_start  = -1.0;   // if >=0, display MD time tau = tau_start + idx*tau_step
+    double tau_step   =  0.0;
+    // Heatmap mode: fix two dimensions, show 2D colour map
+    bool   do_heatmap  = false;
+    int    slice_dim2  = -1, sliceval2 = 0;
+    double heat_scale  = -1.0;  // if >0, fixed symmetric colour scale; else auto
+    Coordinate hotsite({0,0,0,0});
+    bool has_hotsite = false;
+
+    std::string arg;
+    if (GridCmdOptionExists(argv, argv+argc, "--snapdir"))
+        snapdir = GridCmdOptionPayload(argv, argv+argc, "--snapdir");
+    if (GridCmdOptionExists(argv, argv+argc, "--pngdir"))
+        pngdir = GridCmdOptionPayload(argv, argv+argc, "--pngdir");
+    if (GridCmdOptionExists(argv, argv+argc, "--first")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--first");
+        GridCmdOptionInt(arg, first);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--last")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--last");
+        GridCmdOptionInt(arg, last);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--step")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--step");
+        GridCmdOptionInt(arg, step);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--slicedim")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--slicedim");
+        GridCmdOptionInt(arg, slice_dim);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--sliceval")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--sliceval");
+        GridCmdOptionInt(arg, sliceval);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--isosurface")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--isosurface");
+        GridCmdOptionFloat(arg, iso_rms);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--fixediso")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--fixediso");
+        GridCmdOptionFloat(arg, fixed_iso);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--taustart")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--taustart");
+        GridCmdOptionFloat(arg, tau_start);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--taustep")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--taustep");
+        GridCmdOptionFloat(arg, tau_step);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--hotsite")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--hotsite");
+        GridCmdOptionIntVector(arg, hotsite);
+        has_hotsite = true;
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--heatmap"))
+        do_heatmap = true;
+    if (GridCmdOptionExists(argv, argv+argc, "--slicedim2")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--slicedim2");
+        GridCmdOptionInt(arg, slice_dim2);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--sliceval2")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--sliceval2");
+        GridCmdOptionInt(arg, sliceval2);
+    }
+    if (GridCmdOptionExists(argv, argv+argc, "--heatscale")) {
+        arg = GridCmdOptionPayload(argv, argv+argc, "--heatscale");
+        GridCmdOptionFloat(arg, heat_scale);
+    }
+
+    bool do_png = !pngdir.empty();
+    if (do_png) mkdir(pngdir.c_str(), 0755);
+
+    // ── Grid setup ───────────────────────────────────────────────────────────
+    auto latt_size   = GridDefaultLatt();
+    auto simd_layout = GridDefaultSimd(Nd, vComplex::Nsimd());
+    auto mpi_layout  = GridDefaultMpi();
+    GridCartesian grid(latt_size, simd_layout, mpi_layout);
+    LatticeComplexD field(&grid);
+
+    // Force components
+    struct ForceSpec { std::string prefix; std::string label; };
+    std::vector<ForceSpec> forces = {
+        { "F_IwasakiGaugeAction_lat",                                             "Gauge_lat"    },
+        { "F_IwasakiGaugeAction_smr",                                             "Gauge_smr"    },
+        { "F_JacobianAction_smr",                                                 "Jacobian"     },
+        { "F_TwoFlavourEvenOddRatioPseudoFermionActiondet_0.0047_det_0.05_lat",  "Ferm0047_lat" },
+        { "F_TwoFlavourEvenOddRatioPseudoFermionActiondet_0.0047_det_0.05_smr",  "Ferm0047_smr" },
+        { "F_TwoFlavourEvenOddRatioPseudoFermionActiondet_0.05_det_0.1_lat",     "Ferm005_lat"  },
+        { "F_TwoFlavourEvenOddRatioPseudoFermionActiondet_0.1_det_0.25_lat",     "Ferm01_lat"   },
+        { "F_TwoFlavourEvenOddRatioPseudoFermionActiondet_0.25_det_0.5_lat",     "Ferm025_lat"  },
+        { "F_TwoFlavourEvenOddRatioPseudoFermionActiondet_0.5_det_1_lat",        "Ferm05_lat"   },
+    };
+
+    // ── Stdout header ─────────────────────────────────────────────────────────
+    std::cerr << "idx";
+    for (auto& fs : forces) {
+        std::cerr << "\t" << fs.label << "_rms";
+        if (has_hotsite) std::cerr << "\t" << fs.label << "_hot";
+    }
+    std::cerr << "\n";
+
+    // ── Persistent render contexts (one GPU context for all frames) ──────────
+    std::unique_ptr<RenderCtx>    ctx;      // isosurface mode
+    std::unique_ptr<HeatmapCtx>   hctx;    // heatmap mode
+
+    // ── Main loop ─────────────────────────────────────────────────────────────
+    for (int idx = first; idx <= last; idx += step) {
+        std::cerr << idx;
+
+        for (auto& fs : forces) {
+            std::string fname = snapdir + "/" + fs.prefix + "." + std::to_string(idx);
+
+            if (!tryReadFile(field, fname)) {
+                std::cerr << "\t-";
+                if (has_hotsite) std::cerr << "\t-";
+                continue;
+            }
+
+            // RMS (real part)
+            RealD sumsq = 0.0;
+            for (int i = 0; i < grid.gSites(); i++) {
+                Coordinate site;
+                Lexicographic::CoorFromIndex(site, i, latt_size);
+                RealD v = real(peekSite(field, site));
+                sumsq += v * v;
+            }
+            RealD rms = std::sqrt(sumsq / grid.gSites());
+            std::cerr << "\t" << rms;
+
+            if (has_hotsite) {
+                RealD hval = real(TensorRemove(peekSite(field, hotsite)));
+                std::cerr << "\t" << hval;
+            }
+
+            // PNG output (isosurface or heatmap)
+            if (do_png) {
+                // Build title string
+                std::ostringstream title;
+                title << fs.label << "  ";
+                if (tau_start >= 0.0 && tau_step > 0.0) {
+                    double tau = tau_start + idx * tau_step;
+                    title << std::fixed << std::setprecision(6) << "tau=" << tau;
+                } else {
+                    title << "idx=" << idx;
+                }
+                title << "  rms=" << std::scientific << std::setprecision(3) << rms;
+
+                std::ostringstream outpath;
+                outpath << pngdir << "/" << fs.label
+                        << "_" << std::setfill('0') << std::setw(6) << idx << ".png";
+
+                if (do_heatmap && slice_dim2 >= 0) {
+                    // ── Heatmap mode ────────────────────────────────────────
+                    // Display dims = the two that are NOT fixed
+                    std::vector<int> disp;
+                    for (int d = 0; d < 4; d++)
+                        if (d != slice_dim && d != slice_dim2) disp.push_back(d);
+
+                    if (!hctx) {
+                        double sc = (heat_scale > 0) ? heat_scale : rms * 20.0;
+                        // Hotsite projection onto display plane
+                        int hx = -1, hy = -1;
+                        if (has_hotsite) {
+                            hx = hotsite[disp[0]];
+                            hy = hotsite[disp[1]];
+                        }
+                        hctx = std::make_unique<HeatmapCtx>();
+                        hctx->init(latt_size[disp[0]], latt_size[disp[1]], sc, hx, hy);
+                    }
+
+                    title << "  scale=+-" << std::fixed << std::setprecision(4) << hctx->scale;
+                    renderHeatmap(*hctx, field, latt_size,
+                                  slice_dim,  sliceval,
+                                  slice_dim2, sliceval2,
+                                  title.str(), outpath.str());
+                } else {
+                    // ── Isosurface mode ─────────────────────────────────────
+                    double contour = (fixed_iso > 0) ? fixed_iso : iso_rms * rms;
+                    title << "  iso=" << contour;
+
+                    if (!ctx) {
+                        std::vector<int> disp;
+                        for (int d = 0; d < 4; d++) if (d != slice_dim) disp.push_back(d);
+                        ctx = std::make_unique<RenderCtx>();
+                        ctx->init(latt_size[disp[0]], latt_size[disp[1]], latt_size[disp[2]]);
+                    }
+                    renderPNG(*ctx, field, latt_size, slice_dim, sliceval,
+                              contour, title.str(), outpath.str());
+                }
+            }
+        }
+        std::cerr << "\n";
+        std::cerr.flush();
+    }
+
+    Grid_finalize();
+    return EXIT_SUCCESS;
+}

visualisation/TranscriptToVideo.cxx

@@ -0,0 +1,742 @@
+// TranscriptToVideo.cxx
+//
+// Reads a conversation transcript file with [User] / [Claude] turns and
+// renders it to an AVI using vtkFFMPEGWriter at 1280x720, 10 fps.
+//
+// Transcript format:
+//   [USER] Some question or command, possibly spanning
+//          multiple continuation lines.
+//   [ASSISTANT] A response, also possibly
+//               spanning multiple lines.
+//   ...
+//
+// Rules:
+//   - A line beginning "[User]" or "[Claude]" starts a new turn.
+//   - Any subsequent non-blank line that does NOT begin with "[" is a
+//     continuation of the previous turn (joined with a single space).
+//   - Blank lines are ignored.
+//
+// Usage:
+//   ./TranscriptToVideo <transcript.txt> <output.avi>
+//
+// Typewriter speed : 10 chars/sec  →  1 frame/char at 10 fps
+// Pause after turn : 0.5 s         →  5 frames
+// Word-wrap column : 62
+
+#include <vtkActor.h>
+#include <vtkActor2D.h>
+#include <vtkCellArray.h>
+#include <vtkFFMPEGWriter.h>
+#include <vtkNamedColors.h>
+#include <vtkNew.h>
+#include <vtkPoints.h>
+#include <vtkPolyData.h>
+#include <vtkPolyDataMapper2D.h>
+#include <vtkProperty2D.h>
+#include <vtkRenderWindow.h>
+#include <vtkRenderer.h>
+#include <vtkTextActor.h>
+#include <vtkTextProperty.h>
+#include <vtkWindowToImageFilter.h>
+
+#include <algorithm>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+// ---------------------------------------------------------------------------
+// Constants
+// ---------------------------------------------------------------------------
+static const int    WIDTH         = 1280;
+static const int    HEIGHT        = 720;
+static const int    FPS           = 10;
+static const int    CHARS_PER_FRAME = 5;        // 50 chars/sec at 10 fps
+static const int    PAUSE_FRAMES  = 3;          // 0.3 s
+static const int    WRAP_COLS     = 60;
+static const int    MAX_HISTORY   = 18;         // visible completed lines
+static const int    FONT_SIZE     = 18;
+static const int    TITLE_SIZE    = 23;
+static const int    LINE_HEIGHT   = 28;         // pixels between lines
+static const int    MARGIN_LEFT   = 48;
+static const int    MARGIN_TOP    = 58;         // below title bar
+
+// Colours (R, G, B in 0–1)
+static const double COL_BG[3]     = { 0.04, 0.04, 0.10 };   // near-black navy
+static const double COL_USER[3]   = { 1.00, 0.84, 0.00 };   // gold
+static const double COL_CLAUDE[3] = { 0.68, 0.85, 0.90 };   // light steel blue
+static const double COL_TITLE[3]  = { 1.00, 1.00, 1.00 };   // white
+static const double COL_BAR[3]    = { 0.30, 0.55, 0.80 };   // progress bar blue
+static const double COL_LABEL[3]  = { 0.65, 0.65, 0.65 };   // dim grey for speaker tag
+
+// ---------------------------------------------------------------------------
+// Structs
+// ---------------------------------------------------------------------------
+enum class Speaker { User, Claude, Caption };
+
+struct Turn {
+    Speaker     speaker;
+    std::string text;   // full unwrapped text
+};
+
+// A rendered display line (already word-wrapped, tagged with speaker)
+struct DisplayLine {
+    Speaker     speaker;
+    std::string prefix;  // "[USER]      " or "[ASSISTANT] "
+    std::string body;    // wrapped segment
+    bool        isFirst;   // first line of this turn (prefix printed)
+    bool        isBlank;   // spacer between turns (no text rendered)
+    bool        isCaption; // caption update — body holds text (empty = clear)
+    DisplayLine() : speaker(Speaker::User), isFirst(false), isBlank(false), isCaption(false) {}
+};
+
+// ---------------------------------------------------------------------------
+// Replace common multi-byte UTF-8 sequences with ASCII equivalents so that
+// VTK's font renderer (which only handles ASCII reliably) does not crash.
+// Any remaining non-ASCII byte is replaced with '?'.
+// ---------------------------------------------------------------------------
+static std::string SanitiseASCII(const std::string& s)
+{
+    std::string out;
+    out.reserve(s.size());
+    const unsigned char* p = (const unsigned char*)s.data();
+    const unsigned char* end = p + s.size();
+    while (p < end) {
+        unsigned char c = *p;
+        if (c < 0x80) {
+            out += (char)c;
+            ++p;
+        } else if (c == 0xE2 && (p + 2) < end) {
+            // 3-byte sequence starting 0xE2
+            unsigned char b1 = *(p+1), b2 = *(p+2);
+            // U+2018 ' U+2019 '  (0xE2 0x80 0x98 / 0x99)
+            if (b1 == 0x80 && (b2 == 0x98 || b2 == 0x99)) { out += '\''; p += 3; }
+            // U+201C " U+201D "  (0xE2 0x80 0x9C / 0x9D)
+            else if (b1 == 0x80 && (b2 == 0x9C || b2 == 0x9D)) { out += '"'; p += 3; }
+            // U+2013 en-dash (0xE2 0x80 0x93)
+            else if (b1 == 0x80 && b2 == 0x93) { out += '-'; p += 3; }
+            // U+2014 em-dash (0xE2 0x80 0x94)
+            else if (b1 == 0x80 && b2 == 0x94) { out += '-'; p += 3; }
+            // U+2026 ellipsis (0xE2 0x80 0xA6)
+            else if (b1 == 0x80 && b2 == 0xA6) { out += "..."; p += 3; }
+            // U+2192 arrow (0xE2 0x86 0x92)
+            else if (b1 == 0x86 && b2 == 0x92) { out += "->"; p += 3; }
+            // U+00D7 multiplication sign (0xC3 0x97) — caught below, but
+            // U+22xx math operators: replace with '~'
+            else { out += '~'; p += 3; }
+        } else if (c == 0xC3 && (p + 1) < end) {
+            // 2-byte latin-1 supplement
+            unsigned char b1 = *(p+1);
+            if (b1 == 0x97) { out += 'x'; p += 2; }       // U+00D7 ×
+            else if (b1 == 0xB7) { out += '/'; p += 2; }  // U+00F7 ÷
+            else { out += '?'; p += 2; }
+        } else {
+            // Unknown multi-byte: skip the whole sequence
+            out += '?';
+            ++p;
+            while (p < end && (*p & 0xC0) == 0x80) ++p; // skip continuation bytes
+        }
+    }
+    return out;
+}
+
+// ---------------------------------------------------------------------------
+// Strip markdown emphasis markers (* and `) so they don't appear in the video.
+// ---------------------------------------------------------------------------
+static std::string StripMarkdown(const std::string& s)
+{
+    std::string out;
+    out.reserve(s.size());
+    for (char c : s) {
+        if (c == '*' || c == '`') continue;
+        out += c;
+    }
+    return out;
+}
+
+// ---------------------------------------------------------------------------
+// Word-wrap: splits `text` into lines of at most maxCols characters.
+// ---------------------------------------------------------------------------
+static std::vector<std::string> WrapText(const std::string& text, int maxCols)
+{
+    std::vector<std::string> lines;
+    std::istringstream words(text);
+    std::string word, line;
+    while (words >> word) {
+        if (!line.empty() && (int)(line.size() + 1 + word.size()) > maxCols) {
+            lines.push_back(line);
+            line = word;
+        } else {
+            if (!line.empty()) line += ' ';
+            line += word;
+        }
+    }
+    if (!line.empty()) lines.push_back(line);
+    if (lines.empty()) lines.push_back("");
+    return lines;
+}
+
+// ---------------------------------------------------------------------------
+// Parse transcript file into list of Turns.
+// ---------------------------------------------------------------------------
+static std::vector<Turn> ParseTranscript(const std::string& path)
+{
+    std::ifstream f(path);
+    if (!f) {
+        std::cerr << "Cannot open transcript: " << path << "\n";
+        std::exit(1);
+    }
+
+    std::vector<Turn> turns;
+    std::string line;
+    while (std::getline(f, line)) {
+        // Trim trailing CR (Windows files)
+        if (!line.empty() && line.back() == '\r') line.pop_back();
+
+        if (line.empty()) {
+            // Blank line within a dialogue turn = paragraph break.
+            // Caption turns don't support paragraph breaks.
+            if (!turns.empty() && turns.back().speaker != Speaker::Caption) {
+                turns.back().text += '\n';   // '\n' sentinel: expands to blank spacer
+            }
+            continue;
+        }
+
+        if (line.size() >= 6 && line.substr(0, 6) == "[USER]") {
+            Turn t;
+            t.speaker = Speaker::User;
+            t.text    = line.substr(6);
+            while (!t.text.empty() && t.text.front() == ' ') t.text.erase(t.text.begin());
+            t.text = SanitiseASCII(t.text);
+            turns.push_back(std::move(t));
+        } else if (line.size() >= 11 && line.substr(0, 11) == "[ASSISTANT]") {
+            Turn t;
+            t.speaker = Speaker::Claude;
+            t.text    = line.substr(11);
+            while (!t.text.empty() && t.text.front() == ' ') t.text.erase(t.text.begin());
+            t.text = SanitiseASCII(t.text);
+            turns.push_back(std::move(t));
+        } else if (line.size() >= 9 && line.substr(0, 9) == "[CAPTION]") {
+            Turn t;
+            t.speaker = Speaker::Caption;
+            t.text    = line.substr(9);
+            while (!t.text.empty() && t.text.front() == ' ') t.text.erase(t.text.begin());
+            t.text = SanitiseASCII(t.text);
+            turns.push_back(std::move(t));
+        } else if (!turns.empty()) {
+            // Continuation line — strip leading whitespace, preserve as separate line
+            size_t start = line.find_first_not_of(" \t");
+            if (start != std::string::npos) {
+                if (!turns.back().text.empty()) turns.back().text += '\n';
+                turns.back().text += SanitiseASCII(line.substr(start));
+            }
+        }
+    }
+    return turns;
+}
+
+// ---------------------------------------------------------------------------
+// Expand all Turns into DisplayLines (word-wrapped).
+// ---------------------------------------------------------------------------
+static std::vector<DisplayLine> ExpandToDisplayLines(const std::vector<Turn>& turns)
+{
+    std::vector<DisplayLine> out;
+    // Prefix widths kept equal for alignment
+    const std::string userPfx   = "[USER]      ";
+    const std::string claudePfx = "[ASSISTANT] ";
+
+    // Track previous non-caption speaker to know when to insert blank spacers
+    Speaker prevSpeaker = Speaker::Caption; // sentinel: no spacer before first real turn
+    for (size_t ti = 0; ti < turns.size(); ++ti) {
+        const Turn& t = turns[ti];
+
+        // Caption turn: emit one special DisplayLine, no spacer, no history entry
+        if (t.speaker == Speaker::Caption) {
+            DisplayLine dl;
+            dl.isCaption = true;
+            dl.speaker   = Speaker::Caption;
+            // body: whitespace-only → clear; otherwise wrap lines joined with \n
+            std::string trimmed = t.text;
+            size_t first = trimmed.find_first_not_of(" \t\r\n");
+            if (first == std::string::npos) {
+                dl.body = "";   // signal to clear caption
+            } else {
+                // Wrap to ~90 cols for the wider caption zone
+                auto lines = WrapText(trimmed, 90);
+                for (size_t i = 0; i < lines.size(); ++i) {
+                    if (i > 0) dl.body += "\n";
+                    dl.body += lines[i];
+                }
+            }
+            out.push_back(dl);
+            continue;
+        }
+
+        // Insert a blank spacer before each new dialogue turn (not before the first)
+        if (prevSpeaker != Speaker::Caption) {
+            DisplayLine blank;
+            blank.isBlank = true;
+            blank.speaker = t.speaker;
+            out.push_back(blank);
+        }
+        prevSpeaker = t.speaker;
+
+        const std::string& pfx = (t.speaker == Speaker::User) ? userPfx : claudePfx;
+        int bodyWidth = WRAP_COLS - (int)pfx.size();
+        if (bodyWidth < 20) bodyWidth = 20;
+
+        // Split the turn text on '\n' to get individual source lines.
+        // Empty source lines become blank spacers (paragraph breaks within a turn).
+        // Non-empty source lines are stripped of markdown markers and word-wrapped.
+        std::vector<std::string> srcLines;
+        {
+            std::string seg;
+            for (char ch : t.text) {
+                if (ch == '\n') { srcLines.push_back(seg); seg.clear(); }
+                else seg += ch;
+            }
+            srcLines.push_back(seg);
+        }
+
+        bool firstOfTurn = true;
+        for (const auto& srcLine : srcLines) {
+            // Strip markdown emphasis markers
+            std::string stripped = StripMarkdown(srcLine);
+            // Trim leading/trailing whitespace
+            size_t f = stripped.find_first_not_of(" \t");
+            if (f == std::string::npos) {
+                // Blank — paragraph break spacer within the turn
+                DisplayLine blank;
+                blank.isBlank = true;
+                blank.speaker = t.speaker;
+                out.push_back(blank);
+                continue;
+            }
+            size_t l = stripped.find_last_not_of(" \t");
+            stripped = stripped.substr(f, l - f + 1);
+
+            auto wrapped = WrapText(stripped, bodyWidth);
+            for (size_t i = 0; i < wrapped.size(); ++i) {
+                DisplayLine dl;
+                dl.speaker = t.speaker;
+                dl.prefix  = pfx;
+                dl.body    = wrapped[i];
+                dl.isFirst = firstOfTurn && (i == 0);
+                out.push_back(dl);
+            }
+            firstOfTurn = false;
+        }
+    }
+    return out;
+}
+
+// ---------------------------------------------------------------------------
+// Helper: set actor text to `s`, configure font/colour, position.
+// ---------------------------------------------------------------------------
+static void ConfigureTextActor(vtkTextActor* a, int fontSize,
+                               double r, double g, double b)
+{
+    a->GetTextProperty()->SetFontFamilyToCourier();
+    a->GetTextProperty()->SetFontSize(fontSize);
+    a->GetTextProperty()->SetColor(r, g, b);
+    a->GetTextProperty()->SetBold(0);
+    a->GetTextProperty()->SetItalic(0);
+    a->GetTextProperty()->ShadowOff();
+    a->GetTextProperty()->SetJustificationToLeft();
+    a->GetTextProperty()->SetVerticalJustificationToBottom();
+}
+
+// ---------------------------------------------------------------------------
+// Create a thin horizontal progress bar actor (2D polygon).
+// Returns the actor; caller adds to renderer.
+// ---------------------------------------------------------------------------
+static vtkActor2D* MakeProgressBar(vtkPolyData*& pd, vtkPoints*& pts)
+{
+    pts = vtkPoints::New();
+    vtkCellArray* cells = vtkCellArray::New();
+
+    // 4 points, updated every frame
+    pts->SetNumberOfPoints(4);
+    pts->SetPoint(0, 0,   HEIGHT - 8, 0);
+    pts->SetPoint(1, 0,   HEIGHT - 2, 0);
+    pts->SetPoint(2, 100, HEIGHT - 2, 0);
+    pts->SetPoint(3, 100, HEIGHT - 8, 0);
+
+    vtkIdType quad[4] = { 0, 1, 2, 3 };
+    cells->InsertNextCell(4, quad);
+
+    pd = vtkPolyData::New();
+    pd->SetPoints(pts);
+    pd->SetPolys(cells);
+    cells->Delete();
+
+    vtkPolyDataMapper2D* mapper = vtkPolyDataMapper2D::New();
+    mapper->SetInputData(pd);
+
+    vtkActor2D* actor = vtkActor2D::New();
+    actor->SetMapper(mapper);
+    actor->GetProperty()->SetColor(COL_BAR[0], COL_BAR[1], COL_BAR[2]);
+    mapper->Delete();
+    return actor;
+}
+
+// ---------------------------------------------------------------------------
+// Main
+// ---------------------------------------------------------------------------
+int main(int argc, char* argv[])
+{
+    if (argc < 3) {
+        std::cerr << "Usage: TranscriptToVideo <transcript.txt> <output.avi>\n";
+        return 1;
+    }
+    const std::string transcriptPath = argv[1];
+    const std::string outputPath     = argv[2];
+
+    // -----------------------------------------------------------------------
+    // Parse & expand
+    // -----------------------------------------------------------------------
+    auto turns        = ParseTranscript(transcriptPath);
+    auto displayLines = ExpandToDisplayLines(turns);
+    const int totalLines = (int)displayLines.size();
+
+    if (totalLines == 0) {
+        std::cerr << "Transcript has no parseable turns.\n";
+        return 1;
+    }
+
+    // Total frames (rough estimate for progress bar denominator)
+    // Each display line: on average ~40 chars + PAUSE_FRAMES
+    // We'll compute exact total below after knowing char counts.
+    int totalFrames = 0;
+    for (const auto& dl : displayLines) {
+        int chars = (int)dl.body.size();
+        totalFrames += (chars + CHARS_PER_FRAME - 1) / CHARS_PER_FRAME + 1 + PAUSE_FRAMES;
+    }
+
+    // -----------------------------------------------------------------------
+    // VTK Setup
+    // -----------------------------------------------------------------------
+    vtkNew<vtkRenderer>     ren;
+    vtkNew<vtkRenderWindow> renWin;
+
+    ren->SetBackground(COL_BG[0], COL_BG[1], COL_BG[2]);
+    renWin->AddRenderer(ren);
+    renWin->SetSize(WIDTH, HEIGHT);
+    renWin->SetOffScreenRendering(1);
+    renWin->SetMultiSamples(0);
+
+    // -----------------------------------------------------------------------
+    // Title actor
+    // -----------------------------------------------------------------------
+    vtkNew<vtkTextActor> titleActor;
+    titleActor->SetInput("Transcript");
+    ConfigureTextActor(titleActor, TITLE_SIZE,
+                       COL_TITLE[0], COL_TITLE[1], COL_TITLE[2]);
+    titleActor->GetTextProperty()->SetBold(1);
+    titleActor->GetTextProperty()->SetJustificationToCentered();
+    titleActor->SetDisplayPosition(WIDTH / 2, HEIGHT - 36);
+    ren->AddActor2D(titleActor);
+
+    // Thin separator line below title (drawn as a narrow quad)
+    {
+        vtkPoints*    lpts  = vtkPoints::New();
+        vtkCellArray* lcell = vtkCellArray::New();
+        lpts->InsertNextPoint(0,     HEIGHT - 44, 0);
+        lpts->InsertNextPoint(WIDTH, HEIGHT - 44, 0);
+        lpts->InsertNextPoint(WIDTH, HEIGHT - 42, 0);
+        lpts->InsertNextPoint(0,     HEIGHT - 42, 0);
+        vtkIdType q[4] = {0,1,2,3};
+        lcell->InsertNextCell(4, q);
+        vtkPolyData* lpd = vtkPolyData::New();
+        lpd->SetPoints(lpts);
+        lpd->SetPolys(lcell);
+        vtkPolyDataMapper2D* lmap = vtkPolyDataMapper2D::New();
+        lmap->SetInputData(lpd);
+        vtkActor2D* lineActor = vtkActor2D::New();
+        lineActor->SetMapper(lmap);
+        lineActor->GetProperty()->SetColor(0.3, 0.3, 0.5);
+        ren->AddActor2D(lineActor);
+        lpts->Delete(); lcell->Delete(); lpd->Delete();
+        lmap->Delete(); lineActor->Delete();
+    }
+
+    // -----------------------------------------------------------------------
+    // History text actors (MAX_HISTORY lines, reused with shifting content)
+    // -----------------------------------------------------------------------
+    std::vector<vtkTextActor*> histActors(MAX_HISTORY);
+    for (int i = 0; i < MAX_HISTORY; ++i) {
+        histActors[i] = vtkTextActor::New();
+        histActors[i]->SetInput("");
+        ConfigureTextActor(histActors[i], FONT_SIZE, 0.5, 0.5, 0.5);
+        // Position: bottom of history area = just above current-line area
+        int y = MARGIN_TOP + (MAX_HISTORY - 1 - i) * LINE_HEIGHT;
+        histActors[i]->SetDisplayPosition(MARGIN_LEFT, HEIGHT - y);
+        ren->AddActor2D(histActors[i]);
+    }
+
+    // Current (actively typing) line actor — two actors: prefix + body
+    vtkNew<vtkTextActor> curPfxActor;   // "[User]  " in dim colour
+    vtkNew<vtkTextActor> curBodyActor;  // body text in vivid colour
+    vtkNew<vtkTextActor> cursorActor;   // blinking block
+
+    ConfigureTextActor(curPfxActor,  FONT_SIZE, COL_LABEL[0], COL_LABEL[1], COL_LABEL[2]);
+    ConfigureTextActor(curBodyActor, FONT_SIZE, 1, 1, 1);  // will be overridden per turn
+    ConfigureTextActor(cursorActor,  FONT_SIZE, 1, 1, 1);
+
+    cursorActor->SetInput("|");
+
+    int curLineY = HEIGHT - (MARGIN_TOP + MAX_HISTORY * LINE_HEIGHT);
+    // Place current line below history
+    curPfxActor->SetDisplayPosition(MARGIN_LEFT, curLineY);
+    ren->AddActor2D(curPfxActor);
+    ren->AddActor2D(curBodyActor);
+    ren->AddActor2D(cursorActor);
+
+    // -----------------------------------------------------------------------
+    // Progress bar
+    // -----------------------------------------------------------------------
+    vtkPolyData* barPD  = nullptr;
+    vtkPoints*   barPts = nullptr;
+    vtkActor2D*  barActor = MakeProgressBar(barPD, barPts);
+    ren->AddActor2D(barActor);
+
+    // Progress label
+    vtkNew<vtkTextActor> progLabelActor;
+    progLabelActor->SetInput("");
+    ConfigureTextActor(progLabelActor, 13,
+                       COL_LABEL[0], COL_LABEL[1], COL_LABEL[2]);
+    progLabelActor->SetDisplayPosition(MARGIN_LEFT, 12);
+    ren->AddActor2D(progLabelActor);
+
+    // -----------------------------------------------------------------------
+    // Caption actor — bottom-centre, Arial, white, initially hidden
+    // -----------------------------------------------------------------------
+    vtkNew<vtkTextActor> captionActor;
+    captionActor->SetInput("");
+    captionActor->GetTextProperty()->SetFontFamilyToArial();
+    captionActor->GetTextProperty()->SetFontSize(20);
+    captionActor->GetTextProperty()->SetColor(1.0, 1.0, 1.0);
+    captionActor->GetTextProperty()->SetBold(0);
+    captionActor->GetTextProperty()->SetItalic(1);
+    captionActor->GetTextProperty()->ShadowOn();
+    captionActor->GetTextProperty()->SetShadowOffset(1, -1);
+    captionActor->GetTextProperty()->SetJustificationToCentered();
+    captionActor->GetTextProperty()->SetVerticalJustificationToBottom();
+    // Position: centred horizontally, in the gap between typing line and progress label
+    captionActor->SetDisplayPosition(WIDTH / 2, 32);
+    ren->AddActor2D(captionActor);
+
+    // -----------------------------------------------------------------------
+    // FFMPEG writer
+    // -----------------------------------------------------------------------
+    vtkNew<vtkWindowToImageFilter> w2i;
+    w2i->SetInput(renWin);
+    w2i->SetScale(1);
+    w2i->ReadFrontBufferOff();
+
+    vtkNew<vtkFFMPEGWriter> writer;
+    writer->SetInputConnection(w2i->GetOutputPort());
+    writer->SetFileName(outputPath.c_str());
+    writer->SetRate(FPS);
+    writer->SetBitRate(4000);
+    writer->SetBitRateTolerance(400);
+    writer->Start();
+
+    // -----------------------------------------------------------------------
+    // Helper: measure pixel width of a string in the current font
+    // (approximate: Courier is monospace, so width ≈ chars × charWidth)
+    // At font size 17 in Courier, one character ≈ 10.2px wide.
+    // -----------------------------------------------------------------------
+    const double CHAR_PX = 10.2;
+
+    auto bodyX = [&](const std::string& pfx) -> int {
+        return MARGIN_LEFT + (int)(pfx.size() * CHAR_PX);
+    };
+
+    // -----------------------------------------------------------------------
+    // Render one frame
+    // -----------------------------------------------------------------------
+    int frameCount = 0;
+    auto renderFrame = [&]() {
+        renWin->Render();
+        w2i->Modified();
+        writer->Write();
+        ++frameCount;
+    };
+
+    // -----------------------------------------------------------------------
+    // History ring — holds completed display lines (most-recent last)
+    // -----------------------------------------------------------------------
+    std::vector<DisplayLine> history;
+
+    auto refreshHistory = [&]() {
+        // slot 0 = bottom row (newest), slot MAX_HISTORY-1 = top row (oldest).
+        // Brightness fades linearly from 0.85 (slot 0) to 0.20 (slot MAX-1).
+        // Blank spacer lines show as empty strings.
+        // The [USER]/[ASSISTANT] prefix stays at a fixed bright level so the
+        // speaker is always identifiable even in dim history.
+        int n = (int)history.size();
+        for (int slot = 0; slot < MAX_HISTORY; ++slot) {
+            int idx = n - 1 - slot;   // slot 0 → newest, slot MAX-1 → oldest
+            if (idx < 0) {
+                histActors[slot]->SetInput("");
+                continue;
+            }
+            const auto& hl = history[idx];
+            if (hl.isBlank) {
+                histActors[slot]->SetInput("");
+                continue;
+            }
+
+            // Graduated brightness: bright near bottom, dim near top
+            double bodyBright = 0.20 + 0.65 * (1.0 - (double)slot / (MAX_HISTORY - 1));
+
+            const double* col = (hl.speaker == Speaker::User) ? COL_USER : COL_CLAUDE;
+
+            if (hl.isFirst) {
+                // Prefix stays vivid; body fades
+                // We render prefix + body as one string but colour the whole line
+                // at body brightness — a compromise since VTK TextActor is single-colour.
+                // Use a slightly higher floor for the prefix line so the tag is readable.
+                double pfxBright = std::min(1.0, bodyBright + 0.25);
+                std::string txt = hl.prefix + hl.body;
+                histActors[slot]->SetInput(txt.c_str());
+                histActors[slot]->GetTextProperty()->SetColor(
+                    col[0] * pfxBright, col[1] * pfxBright, col[2] * pfxBright);
+            } else {
+                std::string txt = std::string(hl.prefix.size(), ' ') + hl.body;
+                histActors[slot]->SetInput(txt.c_str());
+                histActors[slot]->GetTextProperty()->SetColor(
+                    col[0] * bodyBright, col[1] * bodyBright, col[2] * bodyBright);
+            }
+        }
+    };
+
+    // -----------------------------------------------------------------------
+    // Main animation loop
+    // -----------------------------------------------------------------------
+    int dlIdx = 0;  // index into displayLines
+
+    // Count total turns to feed into progress label
+    // (display line index → turn index: count isFirst lines)
+    int totalTurns = 0;
+    for (const auto& dl : displayLines) if (dl.isFirst) ++totalTurns;
+    int turnsSeen = 0;
+
+    for (int li = 0; li < totalLines; ++li) {
+        const DisplayLine& dl = displayLines[li];
+
+        // Caption update: swap the bottom caption, no history, no typewriter
+        if (dl.isCaption) {
+            captionActor->SetInput(dl.body.c_str());
+            renderFrame();
+            continue;
+        }
+
+        // Blank spacer: push to history silently with no typewriter frames
+        if (dl.isBlank) {
+            history.push_back(dl);
+            refreshHistory();
+            continue;
+        }
+
+        // Vivid colour for current speaker
+        double cr, cg, cb;
+        if (dl.speaker == Speaker::User) {
+            cr = COL_USER[0]; cg = COL_USER[1]; cb = COL_USER[2];
+        } else {
+            cr = COL_CLAUDE[0]; cg = COL_CLAUDE[1]; cb = COL_CLAUDE[2];
+        }
+        curBodyActor->GetTextProperty()->SetColor(cr, cg, cb);
+        cursorActor->GetTextProperty()->SetColor(cr, cg, cb);
+
+        // Prefix: vivid speaker colour for first line, indent for continuation
+        if (dl.isFirst) {
+            curPfxActor->SetInput(dl.prefix.c_str());
+            curPfxActor->GetTextProperty()->SetColor(cr, cg, cb);
+        } else {
+            curPfxActor->SetInput(std::string(dl.prefix.size(), ' ').c_str());
+            curPfxActor->GetTextProperty()->SetColor(0, 0, 0);
+        }
+
+        int bx = bodyX(dl.prefix);
+        curBodyActor->SetDisplayPosition(bx, curLineY);
+        cursorActor->SetDisplayPosition(bx, curLineY);
+
+        if (dl.isFirst) ++turnsSeen;
+
+        // Update progress label
+        {
+            char buf[64];
+            std::snprintf(buf, sizeof(buf), "Turn %d / %d", turnsSeen, totalTurns);
+            progLabelActor->SetInput(buf);
+        }
+
+        // Update progress bar width
+        {
+            double frac = (totalFrames > 0) ? (double)frameCount / totalFrames : 0.0;
+            double barW = frac * (WIDTH - 2 * MARGIN_LEFT);
+            barPts->SetPoint(0, MARGIN_LEFT,        HEIGHT - 8, 0);
+            barPts->SetPoint(1, MARGIN_LEFT,        HEIGHT - 2, 0);
+            barPts->SetPoint(2, MARGIN_LEFT + barW, HEIGHT - 2, 0);
+            barPts->SetPoint(3, MARGIN_LEFT + barW, HEIGHT - 8, 0);
+            barPts->Modified();
+            barPD->Modified();
+        }
+
+        // Typewriter: reveal CHARS_PER_FRAME characters per rendered frame.
+        // Always render the fully-complete state last.
+        const std::string& body = dl.body;
+        int ci = 0;
+        while (true) {
+            curBodyActor->SetInput(body.substr(0, ci).c_str());
+            double cx = bx + ci * CHAR_PX;
+            cursorActor->SetDisplayPosition((int)cx, curLineY);
+            cursorActor->SetVisibility((frameCount % 2 == 0) ? 1 : 0);
+            renderFrame();
+            if (ci >= (int)body.size()) break;
+            ci = std::min(ci + CHARS_PER_FRAME, (int)body.size());
+        }
+
+        // Line is complete — move it to history
+        history.push_back(dl);
+        refreshHistory();
+
+        // Clear current line display
+        curPfxActor->SetInput("");
+        curBodyActor->SetInput("");
+        cursorActor->SetVisibility(0);
+
+        // Pause frames
+        for (int p = 0; p < PAUSE_FRAMES; ++p) {
+            // Update progress bar
+            {
+                double frac = (totalFrames > 0) ? (double)frameCount / totalFrames : 0.0;
+                double barW = frac * (WIDTH - 2 * MARGIN_LEFT);
+                barPts->SetPoint(0, MARGIN_LEFT,        HEIGHT - 8, 0);
+                barPts->SetPoint(1, MARGIN_LEFT,        HEIGHT - 2, 0);
+                barPts->SetPoint(2, MARGIN_LEFT + barW, HEIGHT - 2, 0);
+                barPts->SetPoint(3, MARGIN_LEFT + barW, HEIGHT - 8, 0);
+                barPts->Modified();
+                barPD->Modified();
+            }
+            renderFrame();
+        }
+    }
+
+    // -----------------------------------------------------------------------
+    // Finish
+    // -----------------------------------------------------------------------
+    writer->End();
+
+    // Tidy up manual ref-counted objects
+    barActor->Delete();
+    barPD->Delete();
+    barPts->Delete();
+    for (auto* a : histActors) a->Delete();
+
+    std::cerr << "Wrote " << frameCount << " frames ("
+              << frameCount / FPS << " s) to " << outputPath << "\n";
+    return 0;
+}

visualisation/Visualise5D.cxx

@@ -0,0 +1,729 @@
+// Derived from VTK/Examples/Cxx/Medical2.cxx
+// The example reads a volume dataset, extracts two isosurfaces that
+// represent the skin and bone, and then displays them.
+//
+// Modified heavily by Peter Boyle to display lattice field theory data as movies and compare multiple files
+
+#include <vtkActor.h>
+#include <vtkCamera.h>
+#include <vtkMetaImageReader.h>
+#include <vtkNamedColors.h>
+#include <vtkNew.h>
+#include <vtkOutlineFilter.h>
+#include <vtkPolyDataMapper.h>
+#include <vtkProperty.h>
+#include <vtkRenderWindow.h>
+#include <vtkRenderWindowInteractor.h>
+#include <vtkRenderer.h>
+#include <vtkStripper.h>
+#include <vtkImageData.h>
+#include <vtkVersion.h>
+#include <vtkCallbackCommand.h>
+#include <vtkTextActor.h>
+#include <vtkTextProperty.h>
+
+#define MPEG
+#ifdef MPEG
+#include <vtkFFMPEGWriter.h>
+#endif
+
+#include <vtkProperty2D.h>
+#include <vtkSliderWidget.h>
+#include <vtkSliderRepresentation2D.h>
+#include <vtkWindowToImageFilter.h>
+
+#include <array>
+#include <string>
+
+#include <Grid/Grid.h>
+
+#define USE_FLYING_EDGES
+#ifdef USE_FLYING_EDGES
+#include <vtkFlyingEdges3D.h>
+typedef vtkFlyingEdges3D isosurface;
+#else
+#include <vtkMarchingCubes.h>
+typedef vtkMarchingCubes isosurface;
+#endif
+
+int mpeg = 0 ;
+int framerate = 10;
+
+template <class T> void readFile(T& out, std::string const fname){
+  Grid::emptyUserRecord record;
+  Grid::ScidacReader RD;
+  RD.open(fname);
+  RD.readScidacFieldRecord(out,record);
+  RD.close();
+}
+using namespace Grid;
+
+class FrameUpdater : public vtkCallbackCommand
+{
+public:
+
+  FrameUpdater() {
+    ffile=0;
+    TimerCount = 0;
+    xoff       = 0;
+    t          = 0;
+    imageData = nullptr;
+    timerId = 0;
+    maxCount = -1;
+    old_file=-1;
+  }
+  
+  static FrameUpdater* New()
+  {
+    FrameUpdater* cb = new FrameUpdater;
+    cb->TimerCount = 0;
+    return cb;
+  }
+
+  //
+  // Must map a x,y,z + frame index into
+  // i)  a d-dimensional site Coordinate
+  // ii) a file name
+  // Need a:
+  //     loop_ranges
+  //     sum_ranges
+  //     loop_vol  -- map loop_idx -> loop_coor
+  //     sum_vol   -- map sum_idx -> sum_coor with Lexicographic
+  //
+  /*
+   * Just set this up
+   */
+  int old_file ; // Cache, avoid reread
+  
+  Coordinate          latt;
+  Coordinate          xyz_dims    ; // List lattice dimensions corresponding to xyz_dims displayed 
+  Coordinate          xyz_ranges  ; // 3-vector
+  Coordinate          g_xyz_ranges; // Nd-vector
+  uint64_t            xyz_vol     ;
+  
+  Coordinate          loop_dims;    // List lattice dimensions put into movie time
+  Coordinate          loop_ranges;  // movie time ranges
+  uint64_t            loop_vol;
+
+  Coordinate          sum_dims;      // List lattice dimensions summed
+  Coordinate          sum_ranges;    // summation ranges
+  uint64_t            sum_vol;
+
+  Coordinate          slice_dims;      // List slice dimensions 
+
+  Coordinate          Slice;
+  
+  std::vector<std::string> files;        // file list that is looped over
+
+  int Nd;
+  GridBase *grid;
+  Grid::LatticeComplexD *grid_data;
+
+  void SetGrid(GridBase *_grid)
+  {
+    grid = _grid;
+    Nd=grid->Nd();
+    latt = grid->GlobalDimensions();
+    grid_data = new Grid::LatticeComplexD(grid);
+  }
+
+  void SetFiles(std::vector<std::string> list)      { files = list; old_file = -1; }
+  void SetSlice(Coordinate _Slice)             { Slice = _Slice;} // Offset / skew for lattice coords
+  void SetSumDimensions (Coordinate _SumDims ) {
+    sum_ranges=Coordinate(Nd);
+    sum_dims = _SumDims; // 1 hot for dimensions summed
+    sum_vol = 1;
+    for(int d=0;d<sum_dims.size();d++){
+      if ( sum_dims[d] == 1 ) sum_ranges[d] = latt[d];
+      else                    sum_ranges[d] = 1;
+      sum_vol*=sum_ranges[d];
+    }
+  }
+  void SetLoopDimensions(Coordinate _LoopDims) {
+    loop_ranges=Coordinate(Nd);
+    loop_dims= _LoopDims;
+    loop_vol = 1;
+    for(int d=0;d<loop_dims.size();d++){
+      if ( loop_dims[d] == 1 ) loop_ranges[d] = latt[d];
+      else                     loop_ranges[d] = 1;
+      loop_vol*=loop_ranges[d];
+    }
+  } // 
+  void SetDisplayDimensions(Coordinate _xyz_dims   ) {
+    g_xyz_ranges=Coordinate(Nd);
+    xyz_ranges=Coordinate(3);
+    xyz_dims = _xyz_dims;
+    xyz_vol  = 1;
+    for(int d=0;d<3;d++){
+      xyz_ranges[d] = latt[xyz_dims[d]];
+      xyz_vol *= xyz_ranges[d];
+    }
+    // Find dim extents for grid
+    int dd=0;
+    for(int d=0;d<Nd;d++){
+      g_xyz_ranges[d] = 1;
+      for(int dd=0;dd<3;dd++) {
+	if ( xyz_dims[dd]==d ) {
+	  g_xyz_ranges[d] = latt[d];
+	}
+      }
+    }
+  }
+  void SetSliceDimensions(void) {
+    Coordinate _slice_dims;
+    for ( int d=0;d<Nd;d++){
+      int is_slice = 1;
+      if(g_xyz_ranges[d]>1) is_slice = 0;
+      if(loop_dims[d]) is_slice = 0;
+      if(sum_dims[d] ) is_slice = 0;
+      if(is_slice) _slice_dims.push_back(d);
+    }
+    slice_dims = _slice_dims;
+    std::cout << " Setting Slice Dimensions to "<<slice_dims<<std::endl;
+  }
+  virtual void Execute(vtkObject* caller, unsigned long eventId,void* vtkNotUsed(callData))
+  {
+    const int max=256;
+    char text_string[max];
+
+    auto latt_size = grid->GlobalDimensions();
+    
+    if ( vtkCommand::KeyPressEvent == eventId ) {
+
+      vtkRenderWindowInteractor* iren = static_cast<vtkRenderWindowInteractor*>(caller);
+      std::string key = iren->GetKeySym();
+      std::cout << "Pressed: " << key << std::endl;
+      if (slice_dims.size()>0) {
+	int vert = slice_dims[slice_dims.size()-1];
+	int horz = slice_dims[0];
+	if ( key == "Up" ) {
+	  Slice[vert] = (Slice[vert]+1)%latt[vert];
+	}
+	if ( key == "Down" ) {
+	  Slice[vert] = (Slice[vert]+latt[vert]-1)%latt[vert];
+	}
+	if ( key == "Right" ) {
+	  Slice[horz] = (Slice[horz]+1)%latt[horz];
+	}
+	if ( key == "Left" ) {
+	  Slice[horz] = (Slice[horz]+latt[horz]-1)%latt[horz];
+	}
+      }
+      if ( key == "greater" ) {
+	ffile = (ffile + 1) % files.size();
+      }
+      if ( key == "less" ) {
+	ffile = (ffile - 1 + files.size()) % files.size();
+      }
+      std::cout <<"Slice " <<Slice <<std::endl;
+      std::cout <<"File  " <<ffile <<std::endl;
+    }
+      
+    // Make a new frame for frame index TimerCount
+    if ( vtkCommand::TimerEvent == eventId || vtkCommand::KeyPressEvent == eventId)
+      {
+	int file     = ((this->TimerCount / loop_vol) + ffile )%files.size();
+
+	if ( file != old_file ) {
+	  readFile(*grid_data,files[file]);
+	  old_file = file;
+	}
+
+	RealD max, min, max_abs,min_abs;
+	Coordinate max_site;
+	Coordinate min_site;
+	Coordinate max_abs_site;
+	Coordinate min_abs_site;
+	for(int idx=0;idx<grid->gSites();idx++){
+	  Coordinate site;
+	  Lexicographic::CoorFromIndex (site,idx,latt);
+	  RealD val=real(peekSite(*grid_data,site));
+	  if (idx==0){
+	    max = min = val;
+	    max_abs = min_abs = fabs(val);
+	    max_site = site;
+	    min_site = site;
+	    min_abs_site = site;
+	    max_abs_site = site;
+	  } else {
+	    if ( val > max ) {
+	      max=val;
+	      max_site = site;
+	    }
+	    if ( fabs(val) > max_abs ) {
+	      max_abs=fabs(val);
+	      max_abs_site = site;
+	    }
+	    if ( val < min ) {
+	      min=val;
+	      min_site = site;
+	    }	    
+	    if ( fabs(val) < min_abs ) {
+	      min_abs=fabs(val);
+	      min_abs_site = site;
+	    }	    
+	  }
+	}
+	std::cout << " abs_max "<<max_abs<<" at " << max_abs_site<<std::endl;
+	std::cout << " abs_min "<<min_abs<<" at " << min_abs_site<<std::endl;
+	std::cout << " max "<<max<<" at " << max_site<<std::endl;
+	std::cout << " min "<<min<<" at " << min_site<<std::endl;
+	// Looped dimensions, map index to coordinate
+	int loop_idx = this->TimerCount % loop_vol;
+	Coordinate loop_coor;
+	Lexicographic::CoorFromIndex (loop_coor,loop_idx,loop_ranges);
+	
+	// Loop over xyz sites
+	Coordinate xyz_coor(3);
+	Coordinate g_xyz_coor(Nd);
+	Coordinate sum_coor(Nd);
+	for(uint64_t xyz = 0 ; xyz< xyz_vol; xyz++){
+	  Lexicographic::CoorFromIndex (xyz_coor,xyz,xyz_ranges);
+	  Lexicographic::CoorFromIndex (g_xyz_coor,xyz,g_xyz_ranges);
+	  
+	  RealD sum_value = 0.0;
+	  for(uint64_t sum_idx = 0 ; sum_idx< sum_vol; sum_idx++){
+	    Lexicographic::CoorFromIndex (sum_coor,sum_idx,sum_ranges);
+	    Coordinate site(Nd);
+	    for(int d=0;d<Nd;d++){
+	      site[d] = (sum_coor[d] + loop_coor[d] + g_xyz_coor[d] + Slice[d])%latt[d];
+	    }
+	    sum_value+= real(peekSite(*grid_data,site));
+	    if(xyz==0) std::cout << "sum "<<sum_idx<<" "<<sum_value<<std::endl;
+	  }
+	  imageData->SetScalarComponentFromDouble(xyz_coor[0],xyz_coor[1],xyz_coor[2],0,sum_value);
+	}
+	imageData->Modified();
+
+	std::stringstream ss;
+	ss<< files[file] <<"\nSlice "<<Slice << "\nLoop  " <<loop_coor<<"\nSummed "<<sum_dims;
+
+	text->SetInput(ss.str().c_str());
+	
+
+	vtkRenderWindowInteractor* iren = dynamic_cast<vtkRenderWindowInteractor*>(caller);
+	iren->GetRenderWindow()->Render();
+	  
+      }
+
+    if ( vtkCommand::TimerEvent == eventId ) {
+      ++this->TimerCount;
+      std::cout << " This was a timer event count "<<this->TimerCount << std::endl;
+    }
+  
+    
+    if (this->TimerCount >= this->maxCount) {
+      vtkRenderWindowInteractor* iren = dynamic_cast<vtkRenderWindowInteractor*>(caller);
+      if (this->timerId > -1)
+	{
+        iren->DestroyTimer(this->timerId);
+	}
+    }
+  }
+  
+
+private:
+  int TimerCount;
+  int ffile;
+  int xoff;
+  int t;
+public:
+  vtkImageData* imageData = nullptr;
+  vtkTextActor* text = nullptr;
+  vtkFFMPEGWriter *writer = nullptr;
+  int timerId ;
+  int maxCount ;
+  double rms;
+  
+  isosurface * posExtractor;
+  isosurface * negExtractor;
+};
+class SliderCallback : public vtkCommand
+{
+public:
+    static SliderCallback* New()
+    {
+        return new SliderCallback;
+    }
+    virtual void Execute(vtkObject* caller, unsigned long eventId, void* callData)
+    {
+        vtkSliderWidget *sliderWidget = vtkSliderWidget::SafeDownCast(caller);
+        if (sliderWidget)
+        {
+	  contour = ((vtkSliderRepresentation *)sliderWidget->GetRepresentation())->GetValue();
+        }
+	fu->posExtractor->SetValue(0,  SliderCallback::contour*fu->rms);
+	fu->negExtractor->SetValue(0, -SliderCallback::contour*fu->rms);
+	fu->posExtractor->Modified();
+	fu->negExtractor->Modified();
+    }    
+public:
+  static double contour;
+  FrameUpdater * fu;
+};
+
+FrameUpdater * KBfu;
+void KeypressCallbackFunction(vtkObject* caller, long unsigned int eventId,
+                              void* clientData, void* callData)
+{
+  std::cout << "Keypress callback" << std::endl;
+  vtkRenderWindowInteractor* iren = static_cast<vtkRenderWindowInteractor*>(caller);
+  std::cout << "Pressed: " << iren->GetKeySym() << std::endl;
+  //  imageData->Modified();
+}
+
+double SliderCallback::contour;
+
+int main(int argc, char* argv[])
+{
+  using namespace Grid;
+
+  Grid_init(&argc, &argv);
+  GridLogLayout();
+
+  auto latt_size   = GridDefaultLatt();
+  auto simd_layout = GridDefaultSimd(latt_size.size(), vComplex::Nsimd());
+  auto mpi_layout  = GridDefaultMpi();
+  GridCartesian    Grid(latt_size, simd_layout, mpi_layout);
+
+  double default_contour = 1.0;
+  std::string arg;
+ 
+  std::cout << argc << " command Line arguments "<<std::endl;
+  for(int c=0;c<argc;c++) {
+    std::cout << " - "<<argv[c]<<std::endl;
+  }
+
+  std::vector<std::string> file_list({
+      "file1",
+      "file2",
+      "file3",
+      "file4",
+      "file5",
+      "file6",
+      "file7",
+      "file8"
+    });
+
+  if( GridCmdOptionExists(argv,argv+argc,"--files") ){
+    arg=GridCmdOptionPayload(argv,argv+argc,"--files");
+    GridCmdOptionCSL(arg, file_list);
+  }
+
+#ifdef MPEG
+  if( GridCmdOptionExists(argv,argv+argc,"--mpeg") ){
+    mpeg = 1;
+  }
+#endif
+
+  if( GridCmdOptionExists(argv,argv+argc,"--fps") ){
+    arg=GridCmdOptionPayload(argv,argv+argc,"--fps");
+    GridCmdOptionInt(arg,framerate);
+  }
+  if( GridCmdOptionExists(argv,argv+argc,"--isosurface") ){
+    arg=GridCmdOptionPayload(argv,argv+argc,"--isosurface");
+    GridCmdOptionFloat(arg,default_contour);
+  }
+  for(int c=0;c<file_list.size();c++) {
+    std::cout << " file: "<<file_list[c]<<std::endl;
+  }
+
+  int NoTime = 0;
+  int Nd; Nd = Grid.Nd();
+  Coordinate    Slice(Nd,0);
+  Coordinate  SumDims(Nd,0);
+  Coordinate LoopDims(Nd,0);
+  Coordinate  XYZDims({0,1,2});
+  if( GridCmdOptionExists(argv,argv+argc,"--slice") ){
+    arg=GridCmdOptionPayload(argv,argv+argc,"--slice");
+    GridCmdOptionIntVector(arg,Slice);
+  }
+  if( GridCmdOptionExists(argv,argv+argc,"--sum") ){
+    arg=GridCmdOptionPayload(argv,argv+argc,"--sum");
+    GridCmdOptionIntVector(arg,SumDims);
+  }
+  if( GridCmdOptionExists(argv,argv+argc,"--loop") ){
+    arg=GridCmdOptionPayload(argv,argv+argc,"--loop");
+    GridCmdOptionIntVector(arg,LoopDims);
+  }
+  if( GridCmdOptionExists(argv,argv+argc,"--xyz") ){
+    arg=GridCmdOptionPayload(argv,argv+argc,"--xyz");
+    GridCmdOptionIntVector(arg,XYZDims);
+    std::cout << "xyz : "<<XYZDims<<std::endl;
+  }
+  if( GridCmdOptionExists(argv,argv+argc,"--notime") ){
+    NoTime = 1;
+    std::cout << "Suppressing time loop"<<std::endl;
+  }
+
+  // Common things:
+  vtkNew<vtkNamedColors> colors;
+  std::array<unsigned char, 4> posColor{{240, 184, 160, 255}};  colors->SetColor("posColor", posColor.data());
+  std::array<unsigned char, 4> bkg{{51, 77, 102, 255}};         colors->SetColor("BkgColor", bkg.data());
+
+  // Create the renderer, the render window, and the interactor. The renderer
+  // draws into the render window, the interactor enables mouse- and
+  // keyboard-based interaction with the data within the render window.
+  //
+  vtkNew<vtkRenderWindow> renWin;
+  vtkNew<vtkRenderWindowInteractor> iren;
+  iren->SetRenderWindow(renWin);
+
+  
+  //  std::vector<LatticeComplexD> data(file_list.size(),&Grid);
+  //  FieldMetaData header;
+
+  
+
+  int frameCount = file_list.size();
+  for(int d=0;d<Grid.Nd();d++) {
+    if ( LoopDims[d] ) frameCount*= latt_size[d];
+
+  }
+  // It is convenient to create an initial view of the data. The FocalPoint
+  // and Position form a vector direction. Later on (ResetCamera() method)
+  // this vector is used to position the camera to look at the data in
+  // this direction.
+  vtkNew<vtkCamera> aCamera;
+  aCamera->SetViewUp(0, 0, -1);
+  aCamera->SetPosition(0, -1000, 0);
+  aCamera->SetFocalPoint(0, 0, 0);
+  aCamera->ComputeViewPlaneNormal();
+  aCamera->Azimuth(30.0);
+  aCamera->Elevation(30.0);
+
+    
+  vtkNew<vtkRenderer> aRenderer;
+  renWin->AddRenderer(aRenderer);
+    
+  double vol = Grid.gSites();
+  std::cout << "Reading "<<file_list[0]<<std::endl;
+  double nrm, nrmbar,rms, contour;
+  {
+    LatticeComplexD data(&Grid);
+    readFile(data,file_list[0]);
+    nrm    = norm2(data);
+  }
+  nrmbar = nrm/vol;
+  rms    = sqrt(nrmbar);
+  
+  contour = default_contour * rms; // default to 1 x RMS
+
+  // The following reader is used to read a series of 2D slices (images)
+  // that compose the volume. The slice dimensions are set, and the
+  // pixel spacing. The data Endianness must also be specified. The reader
+  // uses the FilePrefix in combination with the slice number to construct
+  // filenames using the format FilePrefix.%d. (In this case the FilePrefix
+  // is the root name of the file: quarter.)
+  vtkNew<vtkImageData> imageData;
+  imageData->SetDimensions(latt_size[0],latt_size[1],latt_size[2]);
+  imageData->AllocateScalars(VTK_DOUBLE, 1);
+  for(int xx=0;xx<latt_size[0];xx++){
+    for(int yy=0;yy<latt_size[1];yy++){
+      for(int zz=0;zz<latt_size[2];zz++){
+	Coordinate site({xx,yy,zz,0});
+	RealD value = 0;
+	imageData->SetScalarComponentFromDouble(xx,yy,zz,0,value);
+   }}}
+
+  
+  vtkNew<isosurface> posExtractor;
+  posExtractor->SetInputData(imageData);
+  posExtractor->SetValue(0, contour);
+  
+  vtkNew<vtkStripper> posStripper;
+  posStripper->SetInputConnection(posExtractor->GetOutputPort());
+
+  vtkNew<vtkPolyDataMapper> posMapper;
+  posMapper->SetInputConnection(posStripper->GetOutputPort());
+  posMapper->ScalarVisibilityOff();
+
+  vtkNew<vtkActor> pos;
+  pos->SetMapper(posMapper);
+  pos->GetProperty()->SetDiffuseColor(colors->GetColor3d("posColor").GetData());
+  pos->GetProperty()->SetSpecular(0.3);
+  pos->GetProperty()->SetSpecularPower(20);
+  pos->GetProperty()->SetOpacity(0.5);
+
+  // An isosurface, or contour value is set
+  // The triangle stripper is used to create triangle strips from the
+  // isosurface; these render much faster on may systems.
+  vtkNew<isosurface> negExtractor;
+  negExtractor->SetInputData(imageData);
+  negExtractor->SetValue(0, -contour);
+
+  vtkNew<vtkStripper> negStripper;
+  negStripper->SetInputConnection(negExtractor->GetOutputPort());
+
+  vtkNew<vtkPolyDataMapper> negMapper;
+  negMapper->SetInputConnection(negStripper->GetOutputPort());
+  negMapper->ScalarVisibilityOff();
+    
+  vtkNew<vtkActor> neg;
+  neg->SetMapper(negMapper);
+  neg->GetProperty()->SetDiffuseColor(colors->GetColor3d("Ivory").GetData());
+
+  // An outline provides context around the data.
+  vtkNew<vtkOutlineFilter> outlineData;
+  outlineData->SetInputData(imageData);
+
+  vtkNew<vtkPolyDataMapper> mapOutline;
+  mapOutline->SetInputConnection(outlineData->GetOutputPort());
+  
+  vtkNew<vtkActor> outline;
+  outline->SetMapper(mapOutline);
+  outline->GetProperty()->SetColor(colors->GetColor3d("Black").GetData());
+
+  vtkNew<vtkTextActor> Text;
+  //  Text->SetInput(file_list[f].c_str());
+  Text->SetPosition2(0,0);
+  Text->GetTextProperty()->SetFontSize(24);
+  Text->GetTextProperty()->SetColor(colors->GetColor3d("Gold").GetData());
+
+  vtkNew<vtkTextActor> TextT;
+  TextT->SetInput("T=0");
+  TextT->SetPosition(0,.7*1025);
+  TextT->GetTextProperty()->SetFontSize(24);
+  TextT->GetTextProperty()->SetColor(colors->GetColor3d("Gold").GetData());
+    
+  
+  // Actors are added to the renderer. An initial camera view is created.
+  // The Dolly() method moves the camera towards the FocalPoint,
+  // thereby enlarging the image.
+  //    aRenderer->AddActor(Text);
+  aRenderer->AddActor(TextT);
+  aRenderer->AddActor(outline);
+  aRenderer->AddActor(pos);
+  aRenderer->AddActor(neg);
+
+  // Sign up to receive TimerEvent
+  vtkNew<FrameUpdater> fu;
+
+  fu->SetGrid(&Grid);
+  fu->SetFiles(file_list);
+  fu->SetSlice(Slice);
+  fu->SetSumDimensions (SumDims);
+  fu->SetLoopDimensions(LoopDims);
+  fu->SetDisplayDimensions(XYZDims);
+  fu->SetSliceDimensions();
+  
+
+  fu->imageData = imageData;
+  //    fu->grid_data = &data[f];
+  fu->text      = TextT;
+  fu->maxCount = frameCount;
+  fu->posExtractor = posExtractor;
+  fu->negExtractor = negExtractor;
+  fu->rms = rms;
+      
+  iren->AddObserver(vtkCommand::TimerEvent, fu);
+  iren->AddObserver(vtkCommand::KeyPressEvent, fu);
+
+  aRenderer->SetActiveCamera(aCamera);
+  aRenderer->ResetCamera();
+  aRenderer->SetBackground(colors->GetColor3d("BkgColor").GetData());
+  aCamera->Dolly(1.0);
+
+  //    double nf = file_list.size();
+  //    std::cout << " Adding renderer " <<f<<" of "<<nf<<std::endl;
+  aRenderer->SetViewport(0.0, 0.0,1.0 , 1.0);
+
+  // Note that when camera movement occurs (as it does in the Dolly()
+  // method), the clipping planes often need adjusting. Clipping planes
+  // consist of two planes: near and far along the view direction. The
+  // near plane clips out objects in front of the plane; the far plane
+  // clips out objects behind the plane. This way only what is drawn
+  // between the planes is actually rendered.
+  aRenderer->ResetCameraClippingRange();
+    
+
+  // Set a background color for the renderer and set the size of the
+  // render window (expressed in pixels).
+  // Initialize the event loop and then start it.
+  renWin->SetSize(1024, 1024);
+  renWin->SetWindowName("FieldDensity");
+  renWin->Render();
+
+  // Take a pointer to the FrameUpdater for keypress mgt.
+  //  KBfu = fu;
+  //  vtkNew<vtkCallbackCommand> keypressCallback;
+  //  keypressCallback->SetCallback(KeypressCallbackFunction);
+  //  iren->AddObserver(vtkCommand::KeyPressEvent,keypressCallback);
+
+  iren->Initialize();
+
+  if ( mpeg ) {
+#ifdef MPEG
+    vtkWindowToImageFilter *imageFilter = vtkWindowToImageFilter::New();
+    imageFilter->SetInput( renWin );
+    imageFilter->SetInputBufferTypeToRGB();
+    
+    vtkFFMPEGWriter *writer = vtkFFMPEGWriter::New();
+    writer->SetFileName("movie.avi");
+    writer->SetRate(framerate);
+    writer->SetInputConnection(imageFilter->GetOutputPort());
+    writer->Start();
+
+    for(int i=0;i<fu->maxCount;i++){
+	fu->Execute(iren,vtkCommand::TimerEvent,nullptr);
+	imageFilter->Modified();
+	writer->Write();
+    }
+    writer->End();
+    writer->Delete();
+#else
+    assert(-1 && "MPEG support not compiled");
+#endif
+  } else { 
+  
+    // Add control of contour threshold
+    // Create a slider widget
+    vtkSmartPointer<vtkSliderRepresentation2D> sliderRep = vtkSmartPointer<vtkSliderRepresentation2D>::New();
+    sliderRep->SetMinimumValue(0.0);
+    sliderRep->SetMaximumValue(10.0);
+    sliderRep->SetValue(1.0);
+    sliderRep->SetTitleText("Fraction RMS");
+    // Set color properties:
+
+    // Change the color of the knob that slides
+    //  sliderRep->GetSliderProperty()->SetColor(colors->GetColor3d("Green").GetData());
+    sliderRep->GetTitleProperty()->SetColor(colors->GetColor3d("AliceBlue").GetData());
+    sliderRep->GetLabelProperty()->SetColor(colors->GetColor3d("AliceBlue").GetData());
+    sliderRep->GetSelectedProperty()->SetColor(colors->GetColor3d("DeepPink").GetData());
+
+    // Change the color of the bar
+    sliderRep->GetTubeProperty()->SetColor(colors->GetColor3d("MistyRose").GetData());
+    sliderRep->GetCapProperty()->SetColor(colors->GetColor3d("Yellow").GetData());
+    sliderRep->SetSliderLength(0.05);
+    sliderRep->SetSliderWidth(0.025);
+    sliderRep->SetEndCapLength(0.02);
+
+    sliderRep->GetPoint1Coordinate()->SetCoordinateSystemToNormalizedDisplay();
+    sliderRep->GetPoint1Coordinate()->SetValue(0.1, 0.1);
+    sliderRep->GetPoint2Coordinate()->SetCoordinateSystemToNormalizedDisplay();
+    sliderRep->GetPoint2Coordinate()->SetValue(0.9, 0.1);
+  
+    vtkSmartPointer<vtkSliderWidget> sliderWidget = vtkSmartPointer<vtkSliderWidget>::New();
+    sliderWidget->SetInteractor(iren);
+    sliderWidget->SetRepresentation(sliderRep);
+    sliderWidget->SetAnimationModeToAnimate();
+    sliderWidget->EnabledOn();
+    
+    // Create the slider callback
+    vtkSmartPointer<SliderCallback> slidercallback = vtkSmartPointer<SliderCallback>::New();
+    slidercallback->fu = fu;
+    sliderWidget->AddObserver(vtkCommand::InteractionEvent, slidercallback);
+
+    if ( NoTime==0 ) {
+      int timerId = iren->CreateRepeatingTimer(10000/framerate);
+      std::cout << "timerId "<<timerId<<std::endl;
+    }
+
+    // Start the interaction and timer
+    iren->Start();
+  }
+
+  Grid_finalize();
+
+  return EXIT_SUCCESS;
+}