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Grid/examples/Example_pvdagm_v2_3level_DenseCoarseMatrix.cc
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/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./examples/Example_pvdagm_v2_3level_DenseCoarseMatrix.cc
Copyright (C) 2026
Author: Peter Boyle <pboyle@bnl.gov>
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 */
//
// PVdagM three level multigrid on the V2 coarse operator.
//
// STAGES ONE AND TWO: grids, types, subspace, and the L1 and L2 coarsenings.
// The dense bottom and the solves are not here yet.
//
// Differences from Example_pvdagm_mrhs_3level_DenseCoarseMatrix.cc:
//
// * The coarse space is UNVECTORISED (sComplexD). The fine space stays
// vectorised. MultiRHSBlockProject carries the mixed layout.
//
// * One operator, not two. V1 needed GeneralCoarsenedMatrix to coarsen and
// MultiGeneralCoarsenedMatrix to apply, bridged by CopyMatrix. V2 does
// both, and single versus multiRHS is SetGrid on the same object with the
// matrix elements built once.
//
// * Nrhs is unconstrained. V1 required nrhs % vComplex::Nsimd() == 0 because
// its multiRHS grid carried the SIMD in the rhs direction.
//
// * CoarsenOperator takes the subspace vectors, not an Aggregation. It block
// orthonormalises them IN PLACE -- the vectors are far too large to copy
// defensively -- so rawNull is taken first and the RAW vectors are what
// define the L2 null space. Do not insert an Orthogonalise() anywhere:
// projecting a block-orthonormal vector onto its own block-orthonormalised
// aggregation gives e_k, and the near null content is silently gone. The
// ||<psi|psi> - I||_F guard below is what catches that.
//
// Env: LATT LS MASS NBASIS(compile time) NRHS BLOCK BLOCK2 COARSEN_BATCH
// HOT_START CONFIG SUBSPACE_FILE V1_CHECK MRHS_COARSEN
//
#include <Grid/Grid.h>
#include <Grid/lattice/PaddedCell.h>
#include <Grid/stencil/GeneralLocalStencil.h>
#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
#include <Grid/algorithms/multigrid/DenseCoarseMatrix.h>
#include <memory>
using namespace std;
using namespace Grid;
// Compile time so it can be cut down for laptop runs: -DNBASIS=8
#ifndef NBASIS
#define NBASIS 60
#endif
RealD mass = 0.00078;
int Nrhs = 12;
int Ls = 24;
int CoarsenBatch = 9;
std::vector<int> lat_size({48,48,48,96});
// Solver tuning. PRINCIPLE (PB, 2026-08-24): the defaults ARE the current
// optimum, so an unset environment reproduces the best banked result; they
// are updated as and when a better point is found, and every change is
// dated here. Environment variables of the same names override for sweeps.
//
// Current optimum: 2026-08-24, slurm-5335492 F4, 48^3x96 Ls=24 on 288 GCDs,
// 17.2 s/RHS at Nrhs=4, 32.2 s at Nrhs=1 (exact-halo FINAL ~1e-8 pending
// the exact-outer rerun). Smoother mmax == order (full GCR history);
// PB's mmax=1 trial gave 72 vs ~60 outer iterations and was slower.
RealD FineSmootherShift = 0.1;
int FineSmootherOrder = 6;
int FineSmootherMmax = 6;
RealD CoarseSmootherShift = 0.1;
int PowerIterations = 0; // >0: power-iterate the smoother operators before the solves (spectral edge)
// Smoother implementation per level (Smoothers.h):
// gcr : the adaptive PGCR (default, as always)
// replay : run the PGCR with a coefficient recorder for the first
// PolyRecordIters outer steps, then switch to GCRReplaySmoother
// (same polynomial, no inner products) -- 1402.2585 p.13 revisited
// cheb : ChebyshevNonHermitianSmoother, 1/x on [ChebLo,ChebHi], order
// = the GCR step count of that level
std::string FineSmootherMode = "gcr";
std::string CoarseSmootherMode = "gcr";
int PolyRecordIters = 4;
RealD FineChebLo = 3.0, FineChebHi = 137.0; // from the harvested polynomial and PowerIterations edge
RealD CoarseChebLo = 8.0, CoarseChebHi = 45.0;
int CoarseSmootherNstep = 2;
int CoarseSmootherMmax = 2;
RealD CoarseSolverTol = 0.05;
int CoarseSolverOrder = 200;
int CoarseSolverMmax = 16;
RealD OuterTol = 1.0e-8;
int OuterMmax = 4;
int OuterNstep = 8;
// "It's legal to get the same answer faster, not to get a less correct
// answer." (PB, 2026-08-24)
//
// Halo-precision POLICY: reduced-precision (fp32 wire)
// halos belong in the PRECONDITIONER -- the smoother, the V-cycle's own
// residuals, and the coarsening -- and NEVER in the outer Krylov. The
// outer operator's applications define what "converged" means; making them
// sloppy turns the stopping criterion into a statement about the wrong
// operator (measured: solver stops at computed 9.8e-9 while the true
// residual is 3.4e-8). Exactness costs one exact fine matvec per outer
// iteration, a few percent of the solve.
//
// Stencil::SloppyComms is a free runtime setter (Stencil.h:303), so the
// policy is implemented by SCOPED toggling: SetFineSloppy(1) on entering
// the preconditioner / coarsening, SetFineSloppy(0) on leaving. The
// operators default to EXACT. FineSloppyComms therefore now means
// "sloppy inside the preconditioner"; =0 makes everything exact.
int FineSloppyComms = 1;
// SmootherCoeffLog=1 : print the GCR step lengths a_k and orthogonalisation
// coefficients b_kj of BOTH smoothers every call -- the harvest for a fixed
// polynomial smoother (stable coefficients => stationary p(A), no reductions).
int SmootherCoeffLog = 0;
std::function<void(int)> SetFineSloppy = [](int){};
void ParseEnvironment(void)
{
if(getenv("MASS")) mass = atof(getenv("MASS"));
if(getenv("NRHS")) Nrhs = atoi(getenv("NRHS"));
if(getenv("LS")) Ls = atoi(getenv("LS"));
if(getenv("COARSEN_BATCH")) CoarsenBatch= atoi(getenv("COARSEN_BATCH"));
if(getenv("FineSmootherShift")) FineSmootherShift = atof(getenv("FineSmootherShift"));
if(getenv("FineSmootherOrder")) FineSmootherOrder = atoi(getenv("FineSmootherOrder"));
if(getenv("FineSmootherMmax")) FineSmootherMmax = atoi(getenv("FineSmootherMmax"));
if(getenv("CoarseSmootherShift"))CoarseSmootherShift= atof(getenv("CoarseSmootherShift"));
if(getenv("PowerIterations")) PowerIterations = atoi(getenv("PowerIterations"));
if(getenv("FineSmootherMode")) FineSmootherMode = getenv("FineSmootherMode");
if(getenv("CoarseSmootherMode")) CoarseSmootherMode = getenv("CoarseSmootherMode");
if(getenv("PolyRecordIters")) PolyRecordIters = atoi(getenv("PolyRecordIters"));
if(getenv("FineChebLo")) FineChebLo = atof(getenv("FineChebLo"));
if(getenv("FineChebHi")) FineChebHi = atof(getenv("FineChebHi"));
if(getenv("CoarseChebLo")) CoarseChebLo = atof(getenv("CoarseChebLo"));
if(getenv("CoarseChebHi")) CoarseChebHi = atof(getenv("CoarseChebHi"));
if(getenv("CoarseSmootherNstep"))CoarseSmootherNstep= atoi(getenv("CoarseSmootherNstep"));
if(getenv("CoarseSmootherMmax")) CoarseSmootherMmax = atoi(getenv("CoarseSmootherMmax"));
if(getenv("CoarseSolverTol")) CoarseSolverTol = atof(getenv("CoarseSolverTol"));
if(getenv("CoarseSolverOrder")) CoarseSolverOrder = atoi(getenv("CoarseSolverOrder"));
if(getenv("CoarseSolverMmax")) CoarseSolverMmax = atoi(getenv("CoarseSolverMmax"));
if(getenv("OuterTol")) OuterTol = atof(getenv("OuterTol"));
if(getenv("OuterMmax")) OuterMmax = atoi(getenv("OuterMmax"));
if(getenv("FineSloppyComms")) FineSloppyComms = atoi(getenv("FineSloppyComms"));
if(getenv("SmootherCoeffLog")) SmootherCoeffLog = atoi(getenv("SmootherCoeffLog"));
if(getenv("OuterNstep")) OuterNstep = atoi(getenv("OuterNstep"));
if(getenv("LATT")){
Coordinate l;
GridCmdOptionIntVector(std::string(getenv("LATT")),l);
GRID_ASSERT(l.size()==4);
for(int d=0;d<4;d++) lat_size[d]=l[d];
}
std::cout << GridLogMessage << "PARAM: LATT "
<< lat_size[0]<<"."<<lat_size[1]<<"."<<lat_size[2]<<"."<<lat_size[3] << std::endl;
std::cout << GridLogMessage << "PARAM: LS " << Ls << std::endl;
std::cout << GridLogMessage << "PARAM: MASS " << mass << std::endl;
std::cout << GridLogMessage << "PARAM: NBASIS " << NBASIS << std::endl;
std::cout << GridLogMessage << "PARAM: NRHS " << Nrhs << std::endl;
std::cout << GridLogMessage << "PARAM: COARSEN_BATCH " << CoarsenBatch << std::endl;
}
template <class Field>
void saveSubspace(std::vector<Field> &subspace, std::string const fname){
#ifdef HAVE_LIME
Grid::emptyUserRecord record;
Grid::ScidacWriter SW(subspace[0].Grid()->IsBoss());
SW.open(fname);
for (int k = 0; k < (int)subspace.size(); k++) SW.writeScidacFieldRecord(subspace[k], record);
SW.close();
#endif
}
template <class Field>
void loadSubspace(std::vector<Field> &subspace, std::string const fname){
#ifdef HAVE_LIME
Grid::emptyUserRecord record;
Grid::ScidacReader SR;
SR.open(fname);
for (int k = 0; k < (int)subspace.size(); k++) SR.readScidacFieldRecord(subspace[k], record);
SR.close();
#endif
}
//////////////////////////////////////////////////////////////////////
// A = PV^dag M (non-Hermitian)
//////////////////////////////////////////////////////////////////////
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){ Field tmp(in.Grid()); _Mat.M(in,tmp); _PV.Mdag(tmp,out); }
void AdjOp (const Field &in, Field &out){ 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 d=innerProduct(in,out); n1=real(d); n2=norm2(out); }
void HermOp(const Field &in, Field &out){ Field tmp(in.Grid()); Op(in,tmp); AdjOp(tmp,out); }
};
//////////////////////////////////////////////////////////////////////
// ||<v|v> - I||_F over a set of coarse vectors. Small means the raw near null
// content survived the projection; see GramGuard for where a leak lands.
//////////////////////////////////////////////////////////////////////
template<class CoarseField>
RealD GramDefect(std::vector<CoarseField> &v)
{
RealD s2=0.0;
for(int i=0;i<(int)v.size();i++){
for(int j=0;j<(int)v.size();j++){
ComplexD sij=TensorRemove(innerProduct(v[i],v[j]));
ComplexD d=sij-(i==j?ComplexD(1.0):ComplexD(0.0));
s2+=real(d)*real(d)+imag(d)*imag(d);
}
}
return std::sqrt(s2);
}
// On a leak every image collapses to the block unit e_k, the Gram becomes
// N*I, and the defect lands at (N-1)*sqrt(nbasis) -- orders above the ~0.2
// of a content preserving projection. Trip well below that so a mis-set
// threshold costs a log line rather than the run.
template<class CoarseField>
void GramGuard(const std::string &name,std::vector<CoarseField> &v,GridBase *grid)
{
RealD defect = GramDefect(v);
RealD N = (RealD)grid->gSites();
RealD leak = (N-1.0)*std::sqrt((RealD)v.size());
RealD trip = std::sqrt(N);
std::cout << GridLogMessage << "GUARD: ||<"<<name<<"|"<<name<<"> - I||_F = " << defect
<< " (e_k leak would be " << leak << ", trip at " << trip << ")" << std::endl;
GRID_ASSERT( defect < trip );
}
//////////////////////////////////////////////////////////////////////
// Shifted variants for the smoothers
//////////////////////////////////////////////////////////////////////
template<class Matrix,class Field>
class ShiftedPVdagMLinearOperator : public LinearOperatorBase<Field> {
Matrix &_Mat; Matrix &_PV;
public:
RealD shift;
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){ Field tmp(in.Grid()); _Mat.M(in,tmp); _PV.Mdag(tmp,out); out = out + shift*in; }
void AdjOp (const Field &in, Field &out){ 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){ Field tmp(in.Grid()); Op(in,tmp); AdjOp(tmp,out); }
};
template<class Field>
class ShiftedLinearOperator : public LinearOperatorBase<Field> {
LinearOperatorBase<Field> &_Op; RealD shift;
public:
ShiftedLinearOperator(RealD _shift, LinearOperatorBase<Field> &Op) : _Op(Op), shift(_shift) {}
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) { _Op.Op(in,out); out = out + shift*in; }
void AdjOp (const Field &in, Field &out) { _Op.AdjOp(in,out); out = out + shift*in; }
void HermOpAndNorm(const Field &in, Field &out,RealD &n1,RealD &n2){ assert(0); }
void HermOp (const Field &in, Field &out) { Field tmp(in.Grid()); Op(in,tmp); AdjOp(tmp,out); }
};
//////////////////////////////////////////////////////////////////////
// Power iteration on a (non-Hermitian) operator: the spectral edge the
// smoother polynomial must not exceed. Reports
// step 0 : |A v|/|v| on a RANDOM unit v -- a one-sample lower bound on
// sigma_max(A). If this and the converged value agree, the
// operator is near-normal and the spectral picture (R_m(lambda)
// on the spectrum) is trustworthy; if not, the field of values
// sets the safe interval and the spectrum understates it.
// step k : |A v_k|/|v_k| -> |lambda_max| as v_k -> the dominant
// eigenvector; the complex Rayleigh quotient <v,Av> gives its
// phase (real => on the axis). A non-converging oscillation
// means a complex-conjugate pair of equal modulus at the top.
// Uses Op(), not HermOp(): this is the operator the smoother sees.
//////////////////////////////////////////////////////////////////////
template<class Field>
void PowerIteration(const std::string &name, LinearOperatorBase<Field> &Op, GridBase *grid, int iters)
{
GRID_TRACE("PowerIteration");
GridParallelRNG RNG(grid); RNG.SeedFixedIntegers(std::vector<int>({7,11,13,17}));
Field v(grid), Av(grid);
gaussian(RNG,v);
RealD nv = std::sqrt(norm2(v)); v = v*(1.0/nv);
RealD ratio=0.0, ratio0=0.0; ComplexD rq(0.0);
for(int i=0;i<iters;i++){
Op.Op(v,Av);
RealD nAv = std::sqrt(norm2(Av));
rq = innerProduct(v,Av); // v is unit
ratio = nAv;
if ( i==0 ) {
ratio0 = ratio;
std::cout << GridLogMessage << "PowerIteration " << name << " step 0 (random v): |Av|/|v| = " << ratio
<< " [lower bound on sigma_max]" << std::endl;
}
if ( (i%10==0) || (i==iters-1) )
std::cout << GridLogMessage << "PowerIteration " << name << " step " << i << " |Av|/|v| = " << ratio
<< " Rayleigh = (" << real(rq) << "," << imag(rq) << ")" << std::endl;
v = Av*(1.0/nAv);
}
std::cout << GridLogMessage << "PowerIteration " << name << " SUMMARY: |lambda_max| ~ " << ratio
<< " Rayleigh (" << real(rq) << "," << imag(rq) << ")"
<< " phase " << std::atan2(imag(rq),real(rq)) << " rad"
<< " step-0 ratio / converged = " << ratio0/ratio
<< (ratio0/ratio > 1.2 ? " ** non-normal: sigma_max well above |lambda_max| **" : " (near-normal)")
<< std::endl;
}
//////////////////////////////////////////////////////////////////////
// Dense L3 solve on the packed D+1 coarse-coarse field
//////////////////////////////////////////////////////////////////////
template<class DenseType, class CoarseCoarseField>
class MrhsDenseCCSolve : public LinearFunction<CoarseCoarseField> {
public:
DenseType &_Dense;
int _nrhs;
MrhsDenseCCSolve(DenseType &D, int nrhs) : _Dense(D), _nrhs(nrhs) {}
using LinearFunction<CoarseCoarseField>::operator();
virtual void operator()(const CoarseCoarseField &in, CoarseCoarseField &out){
_Dense.ApplyBatch6D(in, out, _nrhs);
}
};
//////////////////////////////////////////////////////////////////////
// mrhs interfaces + single-polynomial mrhs PGCR
//////////////////////////////////////////////////////////////////////
template<class Field>
class MrhsLinearFunction {
public:
virtual void operator()(std::vector<Field> &in, std::vector<Field> &out) = 0;
};
template<class Field>
class MrhsPGCRNonHermitian {
public:
RealD Tolerance; Integer MaxIterations; int mmax,nstep,steps,level;
int ZeroGuess = 0; int FirstCycle = 0;
std::string name = "Level 1";
LinearOperatorBase<Field> &Linop;
MrhsLinearFunction<Field> &Preconditioner;
std::function<void(int)> OnStep; // called with the outer step count after every step (smoother switching)
void Level(int lv){ name = "Level " + std::to_string(lv); level=lv; }
void Name(std::string n){ name = n; }
void SetZeroGuess(int z){ ZeroGuess=z; }
MrhsPGCRNonHermitian(RealD tol,Integer maxit,LinearOperatorBase<Field> &_Linop,MrhsLinearFunction<Field> &Prec,int _mmax,int _nstep)
: Tolerance(tol),MaxIterations(maxit),Linop(_Linop),Preconditioner(Prec),mmax(_mmax),nstep(_nstep){ level=1; }
static RealD vnorm2(std::vector<Field> &x){ RealD s=0; for(auto &f:x) s+=norm2(f); return s; }
static ComplexD vinnerProduct(std::vector<Field> &x,std::vector<Field> &y){ ComplexD s(0); for(int r=0;r<(int)x.size();r++) s+=innerProduct(x[r],y[r]); return s; }
static void vaxpy(std::vector<Field> &z,ComplexD a,std::vector<Field> &x,std::vector<Field> &y){ for(int r=0;r<(int)z.size();r++) axpy(z[r],a,x[r],y[r]); }
void vOp(std::vector<Field> &in,std::vector<Field> &out){ GRID_TRACE("MrhsPGCR::vOp"); for(int r=0;r<(int)in.size();r++) Linop.Op(in[r],out[r]); }
void operator()(std::vector<Field> &src,std::vector<Field> &psi){
RealD cp,ssq,rsq; int nrhs=src.size(); GridBase *grid=src[0].Grid();
ssq=vnorm2(src); rsq=Tolerance*Tolerance*ssq;
std::vector<Field> r(nrhs,grid);
GridStopWatch T; T.Start(); steps=0; FirstCycle=1;
for(int k=0;k<MaxIterations;k++){
cp=GCRnStep(src,psi,rsq);
std::cout<<GridLogMessage<<std::string(level,'\t')<<" "<<name<<" MrhsPGCR("<<mmax<<","<<nstep<<") "<<steps<<" steps cp = "<<cp<<" target "<<rsq<<std::endl;
if(cp<rsq){
T.Stop(); vOp(psi,r); for(int rr=0;rr<nrhs;rr++) axpy(r[rr],-1.0,src[rr],r[rr]);
RealD tr=vnorm2(r);
std::cout<<GridLogMessage<<std::string(level,'\t')<<" "<<name<<" MrhsPGCR: Converged on iteration "<<steps
<<" computed residual "<<std::sqrt(cp/ssq)<<" true residual "<<std::sqrt(tr/ssq)<<" target "<<Tolerance<<std::endl;
std::cout<<GridLogMessage<<std::string(level,'\t')<<" "<<name<<" MrhsPGCR Time elapsed: Total "<<T.Elapsed()<<std::endl;
return;
}
}
std::cout<<GridLogMessage<<"MrhsPGCR: did not converge"<<std::endl;
}
RealD GCRnStep(std::vector<Field> &src,std::vector<Field> &psi,RealD rsq){
RealD cp; ComplexD a,b,rq; int nrhs=src.size(); GridBase *grid=src[0].Grid();
std::vector<Field> r(nrhs,grid),Az(nrhs,grid); // Az: restart residual scratch only
std::vector< std::vector<Field> > q(mmax,std::vector<Field>(nrhs,grid));
std::vector< std::vector<Field> > p(mmax,std::vector<Field>(nrhs,grid));
std::vector<RealD> qq(mmax);
if (ZeroGuess && FirstCycle) { for(int rr=0;rr<nrhs;rr++){ psi[rr]=Zero(); r[rr]=src[rr]; } }
else { vOp(psi,Az); for(int rr=0;rr<nrhs;rr++) r[rr]=src[rr]-Az[rr]; }
FirstCycle=0;
// p[0]=Prec(r), q[0]=A p[0], produced directly in the history slots (no copies)
Preconditioner(r,p[0]); vOp(p[0],q[0]); qq[0]=vnorm2(q[0]); cp=vnorm2(r);
for(int k=0;k<nstep;k++){
steps++; int kp=k+1, peri_k=k%mmax, peri_kp=kp%mmax;
if ( OnStep ) OnStep(steps);
rq=vinnerProduct(q[peri_k],r); a=rq/qq[peri_k];
vaxpy(psi,a,p[peri_k],psi); vaxpy(r,-a,q[peri_k],r); cp=vnorm2(r);
std::cout<<GridLogMessage<<std::string(level,'\t')<<" "<<name<<" MrhsPGCR step["<<steps<<"] resid "<<cp<<" target "<<rsq<<std::endl;
if((k==nstep-1)||(cp<rsq)) return cp;
// New direction straight into its history slot: p=Prec(r), q=A p.
Preconditioner(r,p[peri_kp]);
vOp(p[peri_kp],q[peri_kp]);
int northog=((kp)>(mmax-1))?(mmax-1):(kp);
{
GRID_TRACE("MrhsPGCR orthog");
// Classical Gram-Schmidt: all coefficients against the UN-updated new q
// (independent, batchable), then apply. Complex coefficient: the
// operator is non-Hermitian, real(<q_j,Aq>) alone left q's non-orthogonal.
// Batched per rhs (one fused kernel + one reduction each), the shared
// coefficient summed over rhs on the host, ONE GlobalSumVector.
std::vector<ComplexD> bcoef(northog,ComplexD(0.0)), part;
for(int rr=0;rr<nrhs;rr++){
std::vector<const Field*> qwin(northog);
for(int back=0;back<northog;back++){ int peri_back=(k-back)%mmax; GRID_ASSERT((k-back)>=0); qwin[back]=&q[peri_back][rr]; }
rankInnerProductMulti(part,qwin,q[peri_kp][rr]);
for(int back=0;back<northog;back++) bcoef[back]+=part[back];
}
if(northog) grid->GlobalSumVector(&bcoef[0],northog);
for(int back=0;back<northog;back++){ int peri_back=(k-back)%mmax; bcoef[back]=-bcoef[back]/qq[peri_back]; }
for(int rr=0;rr<nrhs;rr++){
std::vector<const Field*> qwin(northog), pwin(northog);
for(int back=0;back<northog;back++){ int peri_back=(k-back)%mmax; qwin[back]=&q[peri_back][rr]; pwin[back]=&p[peri_back][rr]; }
axpyMulti(p[peri_kp][rr],bcoef,pwin);
axpyMulti(q[peri_kp][rr],bcoef,qwin);
}
}
qq[peri_kp]=vnorm2(q[peri_kp]);
}
GRID_ASSERT(0); return cp;
}
};
//////////////////////////////////////////////////////////////////////
// L2->L3 mrhs V-cycle on the D+1 coarse field
//////////////////////////////////////////////////////////////////////
template<class CoarseField, class CoarseCoarseField>
class MrhsCoarseThreeLevelPrec : public LinearFunction<CoarseField> {
public:
LinearOperatorBase<CoarseField> &_CoarseOp;
LinearFunction<CoarseField> &_CoarseSmoother;
MultiRHSBlockProject<CoarseField> &_Projector;
LinearFunction<CoarseCoarseField> &_CoarseCoarseSolve;
GridBase *_Coarse5d, *_CoarseCoarse5d, *_CoarseCoarseMrhs;
int _nrhs;
MrhsCoarseThreeLevelPrec(LinearOperatorBase<CoarseField> &CoarseOp,
LinearFunction<CoarseField> &CoarseSmoother,
MultiRHSBlockProject<CoarseField> &Projector,
LinearFunction<CoarseCoarseField> &CoarseCoarseSolve,
GridBase *Coarse5d, GridBase *CoarseCoarse5d, GridBase *CoarseCoarseMrhs, int nrhs)
: _CoarseOp(CoarseOp), _CoarseSmoother(CoarseSmoother), _Projector(Projector),
_CoarseCoarseSolve(CoarseCoarseSolve),
_Coarse5d(Coarse5d), _CoarseCoarse5d(CoarseCoarse5d), _CoarseCoarseMrhs(CoarseCoarseMrhs), _nrhs(nrhs) {}
using LinearFunction<CoarseField>::operator();
virtual void operator()(const CoarseField &in, CoarseField &out) {
int nrhs=_nrhs;
CoarseField vec1(in.Grid());
CoarseField vec2(in.Grid());
out = in;
_CoarseOp.Op(out,vec1); sub(vec1,in,vec1);
// restrict, through the mixed blockProject: D+1 coarse in, D+1 cc out
CoarseCoarseField CCsrc(_CoarseCoarseMrhs);
CoarseCoarseField CCsol(_CoarseCoarseMrhs);
_Projector.blockProject(vec1,CCsrc);
// CCsol=Zero(); // Is this necessary?
_CoarseCoarseSolve(CCsrc,CCsol);
_Projector.blockPromote(vec1,CCsol);
add(out,out,vec1);
_CoarseOp.Op(out,vec1); sub(vec1,in,vec1);
// vec2=Zero(); // Zero guess
_CoarseSmoother(vec1,vec2);
add(out,out,vec2);
}
};
//////////////////////////////////////////////////////////////////////
// L1->L2 mrhs V-cycle
//////////////////////////////////////////////////////////////////////
template<class FineField, class MrhsCoarseVector, class FineSmoother>
class MrhsTwoLevelMG : public MrhsLinearFunction<FineField> {
public:
typedef MrhsCoarseVector CoarseVector;
LinearOperatorBase<FineField> &_FineOperator;
FineSmoother &_PostSmoother;
MultiRHSBlockProject<FineField> &_Projector;
LinearFunction<CoarseVector> &_CoarseSolve;
GridBase *_CoarseGrid, *_CoarseGridMrhs;
MrhsTwoLevelMG(LinearOperatorBase<FineField> &FineOp, FineSmoother &Post,
MultiRHSBlockProject<FineField> &Projector, LinearFunction<CoarseVector> &CoarseSolve,
GridBase *CoarseGrid, GridBase *CoarseGridMrhs)
: _FineOperator(FineOp),_PostSmoother(Post),_Projector(Projector),_CoarseSolve(CoarseSolve),
_CoarseGrid(CoarseGrid),_CoarseGridMrhs(CoarseGridMrhs){}
virtual void operator()(std::vector<FineField> &in, std::vector<FineField> &out){
// The whole V-cycle is preconditioner: its fine residuals and the
// smoother run with sloppy halos; the caller (the outer Krylov) gets
// the exact operator back on exit.
GRID_TRACE("MGVcycle");
SetFineSloppy(FineSloppyComms);
int nrhs=in.size(); GridBase *fgrid=in[0].Grid();
std::vector<FineField> vec1(nrhs,fgrid),vec2(nrhs,fgrid);
for(int r=0;r<nrhs;r++) out[r]=in[r];
{ GRID_TRACE("MGFineResidual");
for(int r=0;r<nrhs;r++){ _FineOperator.Op(out[r],vec1[r]); sub(vec1[r],in[r],vec1[r]); }
}
// fine vector -> D+1 coarse, via the mixed blockProject
CoarseVector CsrcMrhs(_CoarseGridMrhs), CsolMrhs(_CoarseGridMrhs);
{ GRID_TRACE("MGProject");
_Projector.blockProject(vec1,CsrcMrhs);
}
CsolMrhs=Zero();
{ GRID_TRACE("MGCoarseSolve");
_CoarseSolve(CsrcMrhs,CsolMrhs);
}
{ GRID_TRACE("MGPromote");
_Projector.blockPromote(vec1,CsolMrhs);
for(int r=0;r<nrhs;r++) add(out[r],out[r],vec1[r]);
}
{ GRID_TRACE("MGFineResidual2");
for(int r=0;r<nrhs;r++){ _FineOperator.Op(out[r],vec1[r]); sub(vec1[r],in[r],vec1[r]); }
}
{ GRID_TRACE("MGPostSmooth");
for(int r=0;r<nrhs;r++){
// vec2[r]=Zero();
_PostSmoother(vec1[r],vec2[r]); add(out[r],out[r],vec2[r]);
}
}
SetFineSloppy(0);
}
};
int main (int argc, char ** argv)
{
Grid_init(&argc,&argv);
ParseEnvironment();
RealD M5=1.8, b=1.5, c=0.5;
const int nbasis=NBASIS;
const int nrhs=Nrhs;
const int batch=CoarsenBatch;
Coordinate mpi = GridDefaultMpi();
Coordinate fsimd= GridDefaultSimd(Nd,vComplex::Nsimd());
GridCartesian * UGrid = SpaceTimeGrid::makeFourDimGrid(lat_size,fsimd,mpi);
GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
GridCartesian * FGrid = SpaceTimeGrid::makeFiveDimGrid(Ls,UGrid);
GridRedBlackCartesian * FrbGrid = SpaceTimeGrid::makeFiveDimRedBlackGrid(Ls,UGrid);
// Level 1 blocking (default 2^4)
Coordinate clatt = lat_size;
Coordinate Block({2,2,3,3}); // L1->L2 blocking; banked optimum 2026-08-24 (env BLOCK overrides)
if ( getenv("BLOCK") ){ GridCmdOptionIntVector(std::string(getenv("BLOCK")),Block); GRID_ASSERT(Block.size()==4); }
for(int d=0;d<4;d++){ GRID_ASSERT(lat_size[d]%Block[d]==0); clatt[d]=lat_size[d]/Block[d]; }
std::cout << GridLogMessage << "Block " << Block << " coarse lattice " << clatt << std::endl;
//////////////////////////////////////////////////////////////////////
// The coarse space is unvectorised. The 5D coarse grid is built here
// rather than through SpaceTimeGrid so the SIMD layout is ours.
//////////////////////////////////////////////////////////////////////
Coordinate c5latt({1,clatt[0],clatt[1],clatt[2],clatt[3]});
Coordinate c5simd({1,1,1,1,1});
Coordinate c5mpi ({1,mpi[0],mpi[1],mpi[2],mpi[3]});
GridCartesian *Coarse5d = new GridCartesian(c5latt,c5simd,c5mpi);
// 6D coarse multiRHS grid: rhs is dim 0, undistributed and unvectorised.
// No divisibility constraint on nrhs, unlike V1.
Coordinate cmlatt({nrhs,1,clatt[0],clatt[1],clatt[2],clatt[3]});
Coordinate cmsimd({1,1,1,1,1,1});
Coordinate cmmpi ({1,1,mpi[0],mpi[1],mpi[2],mpi[3]});
GridCartesian *CoarseMrhs = new GridCartesian(cmlatt,cmsimd,cmmpi);
// 6D coarse grid at the coarsening batch, used only while CoarsenOperator
// runs. The matrix elements survive the change back to nrhs.
Coordinate cblatt({batch,1,clatt[0],clatt[1],clatt[2],clatt[3]});
GridCartesian *CoarseBatch = new GridCartesian(cblatt,cmsimd,cmmpi);
// 6D fine grid carrying the coarsening batch: fine SIMD layout preserved
Coordinate fmlatt({batch,Ls,lat_size[0],lat_size[1],lat_size[2],lat_size[3]});
Coordinate fmsimd({1,1,fsimd[0],fsimd[1],fsimd[2],fsimd[3]});
Coordinate fmmpi ({1,1,mpi[0],mpi[1],mpi[2],mpi[3]});
GridCartesian *FineMrhs = new GridCartesian(fmlatt,fmsimd,fmmpi);
std::cout << GridLogMessage << "Nsimd fine " << FGrid->Nsimd()
<< " coarse " << Coarse5d->Nsimd() << std::endl;
GridParallelRNG RNG4(UGrid); RNG4.SeedFixedIntegers({1,2,3,4});
GridParallelRNG RNG5(FGrid); RNG5.SeedFixedIntegers({5,6,7,8});
//////////////////////////////////////////////////////////////////////
// Gauge field
//////////////////////////////////////////////////////////////////////
LatticeGaugeField Umu(UGrid);
if ( getenv("HOT_START") ) {
std::cout << GridLogMessage << "Hot start gauge field" << std::endl;
SU<Nc>::HotConfiguration(RNG4,Umu);
} else {
std::string file("/ccs/home/poare/ckpoint_lat.1000");
if ( getenv("CONFIG") ) file = std::string(getenv("CONFIG"));
std::cout << GridLogMessage << "Reading gauge field " << file << std::endl;
FieldMetaData header;
NerscIO::readConfiguration(Umu,header,file);
}
MobiusFermionD Ddwf(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,mass,M5,b,c);
MobiusFermionD Dpv (Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,1.0, M5,b,c);
// PVdagM and ShiftedPVdagM are thin wrappers over these same two objects,
// so this one callback controls every fine halo in the program. Default
// EXACT; the preconditioner and the coarsening turn sloppiness on for
// their own scope only (policy note at FineSloppyComms).
SetFineSloppy = [&Ddwf,&Dpv](int sloppy){
Ddwf.SloppyComms(sloppy);
Dpv .SloppyComms(sloppy);
};
SetFineSloppy(0);
std::cout << GridLogMessage << "Fine halo policy: preconditioner+coarsening "
<< (FineSloppyComms ? "SLOPPY (fp32 wire)" : "exact")
<< ", outer Krylov EXACT" << std::endl;
typedef PVdagMLinearOperator<MobiusFermionD,LatticeFermionD> PVdagM_t;
typedef ShiftedPVdagMLinearOperator<MobiusFermionD,LatticeFermionD> ShiftedPVdagM_t;
PVdagM_t PVdagM(Ddwf,Dpv);
//////////////////////////////////////////////////////////////////////
// Level 1 types: unvectorised coarse scalar
//////////////////////////////////////////////////////////////////////
typedef sTComplexD CComplexS;
typedef MultiGeneralCoarsenedOperatorV2<vSpinColourVector,CComplexS,nbasis> CoarseOperator;
typedef CoarseOperator::CoarseVector CoarseVector;
typedef Aggregation<vSpinColourVector,CComplexS,nbasis> Subspace;
NextToNearestStencilGeometry5D geom(Coarse5d);
//////////////////////////////////////////////////////////////////////
// Subspace: load RAW (no Orthogonalise!), or generate.
//
// The Aggregation is scaffolding for CreateSubspaceGCR only. That runs
// entirely on the fine grid and ends in GlobalOrthonormalise, which is a
// whole-lattice Gram-Schmidt, so the coarse grid it holds is never
// dereferenced and may be the unvectorised one.
//////////////////////////////////////////////////////////////////////
std::string subspace_file = "subspace_nb" + std::to_string(nbasis) + ".scidac";
if ( getenv("SUBSPACE_FILE") ) subspace_file = std::string(getenv("SUBSPACE_FILE"));
uint64_t file_exists=0;
if ( UGrid->IsBoss() ){ std::ifstream f(subspace_file); file_exists=f.good()?1:0; }
UGrid->GlobalSum(file_exists);
const int cb=0;
Subspace AggregatesGCR(Coarse5d,FGrid,cb);
if ( file_exists ){
std::cout << GridLogMessage << "*** Loading subspace from disk (kept RAW) ***" << std::endl;
loadSubspace(AggregatesGCR.subspace, subspace_file);
} else {
std::cout << GridLogMessage << "*** GCR subspace generation ***" << std::endl;
AggregatesGCR.CreateSubspaceGCR(RNG5,PVdagM,nbasis);
saveSubspace(AggregatesGCR.subspace, subspace_file);
}
// RAW copy BEFORE CoarsenOperator block-orthonormalises in place.
std::vector<LatticeFermionD> rawNull(nbasis,FGrid);
for(int k=0;k<nbasis;k++) rawNull[k]=AggregatesGCR.subspace[k];
//////////////////////////////////////////////////////////////////////
// L1 coarsening. The fine operator is single RHS, so it is promoted to
// the 6D batch grid; a natively multiRHS fine operator would substitute
// here with no other change.
//////////////////////////////////////////////////////////////////////
CoarseOperator CoarseOpPV(geom,Coarse5d);
CoarseOpPV.SetGrid(CoarseBatch);
std::cout << GridLogMessage << "*** L1 CoarsenOperator, batch "<<batch<<" ***" << std::endl;
SetFineSloppy(FineSloppyComms); // coarsening builds the PRECONDITIONER
if ( getenv("MRHS_COARSEN") ) {
// Promote the single RHS operator and pack the batch: costs an
// ExtractSlice/InsertSlice pair per rhs. Here for the A/B only; this is
// the path a natively multiRHS fine operator would take.
MrhsPromotedOperator<LatticeFermionD> MrhsPVdagM(PVdagM,FGrid,batch);
CoarseOpPV.CoarsenOperator(MrhsPVdagM,FineMrhs,AggregatesGCR.subspace,Coarse5d);
} else {
// PVdagM is single RHS: apply it directly, batch on the coarse side.
CoarseOpPV.CoarsenOperator(PVdagM,AggregatesGCR.subspace,Coarse5d,batch);
}
SetFineSloppy(0);
// Stay on the batch grid: the L2 coarsening drives this operator at the
// batch. It is switched to the solve Nrhs once L2 is built.
//////////////////////////////////////////////////////////////////////
// psi_coarse = P^dag (RAW fine null) -> Galerkin images that carry the
// near null content, and are free: A_c (P psi) = P A psi.
//////////////////////////////////////////////////////////////////////
MultiRHSBlockProject<LatticeFermionD> MrhsProjector;
MrhsProjector.Allocate(nbasis,FGrid,Coarse5d);
MrhsProjector.ImportBasis(AggregatesGCR.subspace); // block orthonormal basis
std::vector<CoarseVector> psi_coarse(nbasis,Coarse5d);
MrhsProjector.blockProject(rawNull,psi_coarse); // RAW vectors in
rawNull.clear(); rawNull.shrink_to_fit();
GramGuard("psi_coarse",psi_coarse,Coarse5d);
//////////////////////////////////////////////////////////////////////
// Optional cross check of the coarse matrix elements against the V1
// path, which needs a vectorised coarse space. Block Gram-Schmidt is
// idempotent, so V1 may re-orthonormalise the same vectors in place
// without a second copy of the subspace.
//////////////////////////////////////////////////////////////////////
if ( getenv("V1_CHECK") ) {
typedef GeneralCoarsenedMatrix <vSpinColourVector,vTComplex,nbasis> LittleDiracOperator;
typedef MultiGeneralCoarsenedMatrix<vSpinColourVector,vTComplex,nbasis> MrhsLittleDiracOperator;
typedef Aggregation <vSpinColourVector,vTComplex,nbasis> SubspaceV;
Coordinate v5latt({1,clatt[0],clatt[1],clatt[2],clatt[3]});
Coordinate v5simd({1,fsimd[0],fsimd[1],fsimd[2],fsimd[3]});
GridCartesian *Coarse5dV = new GridCartesian(v5latt,v5simd,c5mpi);
int nrhs_v1 = vComplex::Nsimd();
Coordinate vmlatt({nrhs_v1,1,clatt[0],clatt[1],clatt[2],clatt[3]});
Coordinate vmsimd({vComplex::Nsimd(),1,1,1,1,1});
GridCartesian *CoarseMrhsV = new GridCartesian(vmlatt,vmsimd,cmmpi);
NextToNearestStencilGeometry5D geomV(Coarse5dV);
SubspaceV AggV(Coarse5dV,FGrid,cb);
for(int k=0;k<nbasis;k++) AggV.subspace[k]=AggregatesGCR.subspace[k];
LittleDiracOperator LittleDiracOpPV(geomV,FGrid,Coarse5dV);
std::cout << GridLogMessage << "*** V1 CoarsenOperator (cross check) ***" << std::endl;
SetFineSloppy(FineSloppyComms);
LittleDiracOpPV.CoarsenOperator(PVdagM,AggV);
SetFineSloppy(0);
MrhsLittleDiracOperator mrhsV1(geomV,CoarseMrhsV);
mrhsV1.CopyMatrix(LittleDiracOpPV);
// BLAS_A is written by GridtoBLAS in lSite order and both sides carry
// the same scalar_object, so the two are directly comparable.
typedef MrhsLittleDiracOperator::calcMatrix calcMatrix;
int npoint = geom.npoint;
RealD num=0.0, den=0.0;
for(int p=0;p<npoint;p++){
int64_t sites = mrhsV1.BLAS_A[p].size();
GRID_ASSERT(sites == (int64_t)CoarseOpPV.BLAS_A[p].size());
std::vector<calcMatrix> h1(sites),h2(sites);
acceleratorCopyFromDevice(&mrhsV1.BLAS_A[p][0], &h1[0],sites*sizeof(calcMatrix));
acceleratorCopyFromDevice(&CoarseOpPV.BLAS_A[p][0],&h2[0],sites*sizeof(calcMatrix));
ComplexD *w1=(ComplexD *)&h1[0];
ComplexD *w2=(ComplexD *)&h2[0];
int64_t words = sites*sizeof(calcMatrix)/sizeof(ComplexD);
for(int64_t i=0;i<words;i++){
ComplexD d=w1[i]-w2[i];
num += real(d)*real(d)+imag(d)*imag(d);
den += real(w1[i])*real(w1[i])+imag(w1[i])*imag(w1[i]);
}
}
std::cout << GridLogMessage << "V1_CHECK: |A_V1|^2 = " << den << std::endl;
std::cout << GridLogMessage << "V1_CHECK: |A_V1 - A_V2|^2 / |A_V1|^2 = " << num/den << std::endl;
GRID_ASSERT( den > 0.0 );
GRID_ASSERT( num/den < 1.0e-18 );
}
//////////////////////////////////////////////////////////////////////
// STAGE TWO: L2 -> L3.
//
// The fine operator here is V2 at L1, which is natively multiRHS, so the
// multiRHS driver applies with no promotion adapter: its D+1 grid IS the
// batch grid the L1 operator is currently set to.
//////////////////////////////////////////////////////////////////////
Coordinate cclatt = clatt;
Coordinate Block2({4,4,2,4}); // L2->L3 blocking; banked optimum 2026-08-24 (env BLOCK2 overrides)
if ( getenv("BLOCK2") ){ GridCmdOptionIntVector(std::string(getenv("BLOCK2")),Block2); GRID_ASSERT(Block2.size()==4); }
for(int d=0;d<4;d++){ GRID_ASSERT(clatt[d]%Block2[d]==0); cclatt[d]=clatt[d]/Block2[d]; }
std::cout << GridLogMessage << "Block2 " << Block2 << " coarse-coarse lattice " << cclatt << std::endl;
Coordinate cc5latt({1,cclatt[0],cclatt[1],cclatt[2],cclatt[3]});
GridCartesian *CoarseCoarse5d = new GridCartesian(cc5latt,c5simd,c5mpi);
Coordinate ccmlatt({nrhs,1,cclatt[0],cclatt[1],cclatt[2],cclatt[3]});
GridCartesian *CoarseCoarseMrhs = new GridCartesian(ccmlatt,cmsimd,cmmpi);
Coordinate ccblatt({batch,1,cclatt[0],cclatt[1],cclatt[2],cclatt[3]});
GridCartesian *CoarseCoarseBatch = new GridCartesian(ccblatt,cmsimd,cmmpi);
// Coarsening deepens the tensor nest by one iScalar
typedef CoarseVector::vector_object CoarseSiteObj;
typedef iScalar<CComplexS> CComplexS2;
typedef MultiGeneralCoarsenedOperatorV2<CoarseSiteObj,CComplexS2,nbasis> CoarseCoarseOperator;
typedef CoarseCoarseOperator::CoarseVector CoarseCoarseVector;
NextToNearestStencilGeometry5D geom2(CoarseCoarse5d);
// RAW copy of the coarse null vectors, for the same reason as rawNull:
// the L2 CoarsenOperator block-orthonormalises its subspace in place, and
// the L3 basis must be defined by the vectors that still carry content.
std::vector<CoarseVector> rawPsi(nbasis,Coarse5d);
for(int k=0;k<nbasis;k++) rawPsi[k]=psi_coarse[k];
CoarseCoarseOperator CoarseOpL2(geom2,CoarseCoarse5d);
CoarseOpL2.SetGrid(CoarseCoarseBatch);
NonHermitianLinearOperator<CoarseOperator,CoarseVector> LinOpCoarse(CoarseOpPV);
std::cout << GridLogMessage << "*** L2 CoarsenOperator, batch "<<batch<<" ***" << std::endl;
CoarseOpL2.CoarsenOperator(LinOpCoarse,CoarseBatch,psi_coarse,CoarseCoarse5d);
//////////////////////////////////////////////////////////////////////
// Both operators to the solve Nrhs. The matrix elements are Nrhs
// independent and survive the change.
//////////////////////////////////////////////////////////////////////
CoarseOpPV.SetGrid(CoarseMrhs);
CoarseOpL2.SetGrid(CoarseCoarseMrhs);
std::cout << GridLogMessage << "L1 operator at Nrhs " << CoarseOpPV.Nrhs()
<< ", L2 operator at Nrhs " << CoarseOpL2.Nrhs() << std::endl;
//////////////////////////////////////////////////////////////////////
// psi_cc from the RAW coarse null vectors, and the same guard
//////////////////////////////////////////////////////////////////////
MultiRHSBlockProject<CoarseVector> MrhsProjectorL2;
MrhsProjectorL2.Allocate(nbasis,Coarse5d,CoarseCoarse5d);
MrhsProjectorL2.ImportBasis(psi_coarse); // block orthonormal basis
{
std::vector<CoarseCoarseVector> psi_cc(nbasis,CoarseCoarse5d);
MrhsProjectorL2.blockProject(rawPsi,psi_cc); // RAW vectors in
GramGuard("psi_cc",psi_cc,CoarseCoarse5d);
}
rawPsi.clear(); rawPsi.shrink_to_fit();
//////////////////////////////////////////////////////////////////////
// Both coarse operators apply on their solve grids
//////////////////////////////////////////////////////////////////////
{
GridParallelRNG cRNG(Coarse5d); cRNG.SeedFixedIntegers({3,4,5,6});
CoarseVector cin(CoarseMrhs), cout_(CoarseMrhs);
random(cRNG,cin);
CoarseOpPV.M(cin,cout_);
std::cout << GridLogMessage << "L1 apply |in|^2 = " << norm2(cin)
<< " |M in|^2 = " << norm2(cout_) << std::endl;
GRID_ASSERT( norm2(cout_) > 0.0 );
GridParallelRNG ccRNG(CoarseCoarse5d); ccRNG.SeedFixedIntegers({7,8,9,10});
CoarseCoarseVector ccin(CoarseCoarseMrhs), ccout(CoarseCoarseMrhs);
random(ccRNG,ccin);
CoarseOpL2.M(ccin,ccout);
std::cout << GridLogMessage << "L2 apply |in|^2 = " << norm2(ccin)
<< " |M in|^2 = " << norm2(ccout) << std::endl;
GRID_ASSERT( norm2(ccout) > 0.0 );
}
//////////////////////////////////////////////////////////////////////
// STAGE THREE (part one): the dense bottom on L2.
//
// DenseCoarseMatrix is bilingual: it takes the elements through
// Geometry()/ExtractMatrix(), so the V2 operator serves directly. It does
// detect that a multiRHS op cannot apply on the D dimensional grid and
// skips its own certificate and VERIFY, so the equivalent check is done
// here instead, driving the L2 operator at Nrhs 1 through a slice.
//////////////////////////////////////////////////////////////////////
typedef DenseCoarseMatrix<CComplexS2,nbasis> DenseCC_t;
std::unique_ptr<DenseCC_t> DenseCC;
if ( getenv("DENSE_CC")==nullptr || atoi(getenv("DENSE_CC")) ) {
std::cout << GridLogMessage << "*** L3 dense bottom: import from the V2 L2 operator ***" << std::endl;
DenseCC.reset(new DenseCC_t(CoarseCoarse5d));
DenseCC->Import(CoarseOpL2);
////////////////////////////////////////////////////////////////////
// ||A Ainv x - x|| / ||x||, the check Import could not run itself
////////////////////////////////////////////////////////////////////
Coordinate cc1latt({1,1,cclatt[0],cclatt[1],cclatt[2],cclatt[3]});
GridCartesian *CoarseCoarseOne = new GridCartesian(cc1latt,cmsimd,cmmpi);
CoarseOpL2.SetGrid(CoarseCoarseOne);
CoarseCoarseVector x(CoarseCoarse5d),y(CoarseCoarse5d),z(CoarseCoarse5d);
GridParallelRNG dRNG(CoarseCoarse5d); dRNG.SeedFixedIntegers({11,12,13,14});
random(dRNG,x);
(*DenseCC)(x,y); // y = Ainv x
CoarseCoarseVector y1(CoarseCoarseOne),z1(CoarseCoarseOne);
InsertSliceFast(y,y1,0,0);
CoarseOpL2.M(y1,z1); // z = A y
ExtractSliceFast(z,z1,0,0);
z = z - x;
RealD rel = std::sqrt(norm2(z)/norm2(x));
std::cout << GridLogMessage << "L3 dense: ||A Ainv x - x||/||x|| = " << rel << std::endl;
GRID_ASSERT( rel < 1.0e-2 );
CoarseOpL2.SetGrid(CoarseCoarseMrhs);
delete CoarseCoarseOne;
}
//////////////////////////////////////////////////////////////////////
// STAGE THREE (part two): the solves.
//
// Both operators are driven from the SAME objects at whatever Nrhs is
// asked for -- the matrix elements were built once and survive SetGrid --
// so single RHS and multiRHS are the same code path with a different grid.
//////////////////////////////////////////////////////////////////////
GRID_ASSERT(DenseCC != nullptr); // the PGCR bottom is not ported yet
typedef PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> FineSmoother_t;
ShiftedPVdagM_t ShiftedPVdagM(FineSmootherShift,Ddwf,Dpv);
TrivialPrecon<LatticeFermionD> simple_fine;
TrivialPrecon<CoarseVector> simpleC;
auto RunSolve = [&](int nr)
{
std::cout << GridLogMessage << "**********************************************" << std::endl;
std::cout << GridLogMessage << " V2 THREE-level solve, Nrhs = " << nr << std::endl;
std::cout << GridLogMessage << "**********************************************" << std::endl;
Coordinate cml({nr,1,clatt[0],clatt[1],clatt[2],clatt[3]});
Coordinate ccml({nr,1,cclatt[0],cclatt[1],cclatt[2],cclatt[3]});
GridCartesian *CMrhs = new GridCartesian(cml, cmsimd,cmmpi);
GridCartesian *CCMrhs = new GridCartesian(ccml,cmsimd,cmmpi);
CoarseOpPV.SetGrid(CMrhs);
CoarseOpL2.SetGrid(CCMrhs);
NonHermitianLinearOperator<CoarseOperator,CoarseVector> LinOpC (CoarseOpPV);
NonHermitianLinearOperator<CoarseCoarseOperator,CoarseCoarseVector> LinOpCC(CoarseOpL2);
MrhsDenseCCSolve<DenseCC_t,CoarseCoarseVector> ccSolve(*DenseCC,nr);
ShiftedLinearOperator<CoarseVector> ShiftedC(CoarseSmootherShift, LinOpC);
if ( PowerIterations > 0 ) {
// Spectral edges the smoother polynomials must respect (see
// scripts/gcr_polynomial.py: |R_m|>1 beyond the edge = amplification).
PowerIteration<CoarseVector> ("CoarseSmootherOp(shift="+std::to_string(CoarseSmootherShift)+")", ShiftedC, CMrhs, PowerIterations);
PowerIteration<CoarseVector> ("CoarseOp(unshifted)", LinOpC, CMrhs, PowerIterations);
PowerIteration<LatticeFermionD>("FineSmootherOp(shift="+std::to_string(FineSmootherShift)+")", ShiftedPVdagM, Ddwf.FermionGrid(), PowerIterations);
}
PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>
CoarseSmootherGCR(0.01,1,ShiftedC,simpleC,CoarseSmootherMmax,CoarseSmootherNstep);
CoarseSmootherGCR.Level(2); CoarseSmootherGCR.Name("Csmoother"); CoarseSmootherGCR.SetZeroGuess(1);
SwitchableSmoother<CoarseVector> CoarseSmootherSlot(CoarseSmootherGCR,"Csmoother GCR");
MrhsCoarseThreeLevelPrec<CoarseVector,CoarseCoarseVector>
L2to3Precon(LinOpC, CoarseSmootherSlot, MrhsProjectorL2, ccSolve,
Coarse5d, CoarseCoarse5d, CCMrhs, nr);
PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>
L2PGCR(CoarseSolverTol, CoarseSolverOrder/16, LinOpC, L2to3Precon, CoarseSolverMmax, 16);
L2PGCR.Level(2); L2PGCR.Name("Couter"); L2PGCR.SetZeroGuess(1);
FineSmoother_t SmootherGCR(0.0,1,ShiftedPVdagM,simple_fine,FineSmootherMmax,FineSmootherOrder);
SmootherGCR.Level(1); SmootherGCR.Name("Fsmoother"); SmootherGCR.SetZeroGuess(1);
SmootherGCR.LogCoefficients(SmootherCoeffLog);
CoarseSmootherGCR.LogCoefficients(SmootherCoeffLog);
SwitchableSmoother<LatticeFermionD> FineSmootherSlot(SmootherGCR,"Fsmoother GCR");
MrhsTwoLevelMG<LatticeFermionD,CoarseVector,SwitchableSmoother<LatticeFermionD> >
ThreeLevelPrecon(PVdagM, FineSmootherSlot, MrhsProjector, L2PGCR, Coarse5d, CMrhs);
MrhsPGCRNonHermitian<LatticeFermionD>
L1PGCR(OuterTol,1000,PVdagM,ThreeLevelPrecon,OuterMmax,OuterNstep);
L1PGCR.Level(1); L1PGCR.Name("Fouter"); L1PGCR.SetZeroGuess(1);
//////////////////////////////////////////////////////////////////////
// Smoother modes. Objects live for the duration of this RunSolve.
//////////////////////////////////////////////////////////////////////
std::unique_ptr<ChebyshevNonHermitianSmoother<LatticeFermionD> > FineCheb;
std::unique_ptr<ChebyshevNonHermitianSmoother<CoarseVector> > CoarseCheb;
std::unique_ptr<GCRReplaySmoother<LatticeFermionD> > FineReplay;
std::unique_ptr<GCRReplaySmoother<CoarseVector> > CoarseReplay;
GCRCoefficients recF, recC;
if ( FineSmootherMode == "cheb" ) {
FineCheb.reset(new ChebyshevNonHermitianSmoother<LatticeFermionD>(FineChebLo,FineChebHi,FineSmootherOrder,ShiftedPVdagM));
FineSmootherSlot.Set(*FineCheb,"Fsmoother Chebyshev");
}
if ( CoarseSmootherMode == "cheb" ) {
CoarseCheb.reset(new ChebyshevNonHermitianSmoother<CoarseVector>(CoarseChebLo,CoarseChebHi,CoarseSmootherNstep,ShiftedC));
CoarseSmootherSlot.Set(*CoarseCheb,"Csmoother Chebyshev");
}
if ( FineSmootherMode == "replay" ) SmootherGCR.SetCoefficientRecorder(&recF);
if ( CoarseSmootherMode == "replay" ) CoarseSmootherGCR.SetCoefficientRecorder(&recC);
L1PGCR.OnStep = [&](int step){
if ( step != PolyRecordIters ) return;
if ( FineSmootherMode == "replay" ) {
SmootherGCR.SetCoefficientRecorder(nullptr);
recF.Report("Fsmoother");
FineReplay.reset(new GCRReplaySmoother<LatticeFermionD>(ShiftedPVdagM,recF));
FineSmootherSlot.Set(*FineReplay,"Fsmoother replay");
}
if ( CoarseSmootherMode == "replay" ) {
CoarseSmootherGCR.SetCoefficientRecorder(nullptr);
recC.Report("Csmoother");
CoarseReplay.reset(new GCRReplaySmoother<CoarseVector>(ShiftedC,recC));
CoarseSmootherSlot.Set(*CoarseReplay,"Csmoother replay");
}
};
std::cout << GridLogMessage << "Smoother modes: fine " << FineSmootherMode << " coarse " << CoarseSmootherMode
<< (FineSmootherMode=="replay"||CoarseSmootherMode=="replay" ? " (record for "+std::to_string(PolyRecordIters)+" outer steps)" : "")
<< std::endl;
std::vector<LatticeFermionD> src(nr,FGrid), sol(nr,FGrid);
for(int r=0;r<nr;r++){ gaussian(RNG5,src[r]); sol[r]=Zero(); }
GridStopWatch w; w.Start();
L1PGCR(src,sol);
w.Stop();
std::cout << GridLogMessage << "V2 3-level solve Nrhs "<<nr<<" total " << w.Elapsed()
<< " (per RHS: " << w.useconds()/1.0e6/nr << " s)" << std::endl;
// The outer operator is exact by policy; assert the state rather than
// trust it -- a preconditioner that failed to restore would surface here.
SetFineSloppy(0);
{ LatticeFermionD Ax(FGrid); RealD worst=0.0;
for(int r=0;r<nr;r++){ PVdagM.Op(sol[r],Ax); Ax=Ax-src[r];
RealD rn=std::sqrt(norm2(Ax)/norm2(src[r]));
std::cout << GridLogMessage << "FINAL Nrhs "<<nr<<": rhs["<<r<<"] true residual = " << rn << std::endl;
worst=std::max(worst,rn); }
std::cout << GridLogMessage << "FINAL Nrhs "<<nr<<": worst-case residual = " << worst
<< " (exact-halo verification)" << std::endl;
}
// The operators borrow these grids and build a PaddedCell on them, so
// they must let go before the grids are destroyed.
CoarseOpPV.ReleaseGrid();
CoarseOpL2.ReleaseGrid();
delete CMrhs; delete CCMrhs;
};
RunSolve(nrhs);
if ( getenv("SOLVE_SRHS")==nullptr || atoi(getenv("SOLVE_SRHS")) ) RunSolve(1);
std::cout << GridLogMessage << "*** stage three complete: solves done ***" << std::endl;
Grid_finalize();
}