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Grid/examples/Example_pvdagm_mrhs_3level.cc
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2026-09-29 12:36:34 -04:00

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/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./examples/Example_pvdagm_mrhs_3level.cc
Copyright (C) 2026
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.
See the full license in the file "LICENSE" in the top level distribution directory
*************************************************************************************/
/* END LEGAL */
// MultiRHS (valence) THREE-level multigrid for PVdagM.
//
// This is exactly the plain three-level algorithm of Example_pvdagm_3level_SVDdefl.cc
// with L3_DEFL=0 (NO deflation), applied to the enlarged block-diagonal mRHS system:
// the coarse and coarse-coarse levels run a SINGLE Krylov (one GCR polynomial, inner
// products summed over rhs) on the packed 6D mrhs fields, so both coarse levels batch
// through GEMM (DeprecatedMultiGeneralCoarsenedMatrix) -- the valence throughput win at BOTH levels.
//
// Level structure (each coarse level is a single-field PGCR on a packed 6D mrhs field):
// L1 (fine) : std::vector<LatticeFermionD>, MrhsPGCRNonHermitian on PVdagM,
// preconditioned by the L1->L2 mrhs V-cycle (MrhsTwoLevelMG).
// L2 (coarse) : 6D mrhs coarse field, PGCR, preconditioned by the L2->L3 mrhs
// V-cycle (MrhsCoarseThreeLevelPrec) -- coarse-coarse correction + coarse smoother.
// L3 (coarse-coarse): 6D mrhs coarse-coarse field, PGCR (the innermost solve).
//
// RAW-NULL DISCIPLINE (critical -- see project_block_orthogonalise_leak): the L2->L3
// aggregation MUST be built from RAW fine near-null vectors (pre block-GS). We take a
// raw copy of the loaded subspace BEFORE the L1->L2 CoarsenOperator (which block-
// orthonormalises in place) and project THAT. Guards print ||<psi|psi> - I||: ~0.23 =
// content preserved, ~N_coarse = the e_k leak is back.
//
// Env: MASS SUBSPACE_FILE NRHS
// BLOCK (dotted, default 2.2.2.2) BLOCK2 (dotted, default 2.2.3.3)
// FineSmootherShift FineSmootherOrder
// CoarseSmootherShift CoarseSmootherNstep
// CoarseSolverTol CoarseSolverOrder
// L3_TOL L3_MAXIT L3_NSTEP
// OuterMmax OuterNstep OuterTol
#include <Grid/Grid.h>
#include <Grid/lattice/PaddedCell.h>
#include <Grid/stencil/GeneralLocalStencil.h>
#include <Grid/algorithms/iterative/PrecGeneralisedConjugateResidualNonHermitian.h>
#include <Grid/algorithms/multigrid/MrhsMultiGrid.h>
using namespace std;
using namespace Grid;
RealD FineSmootherShift = 0.1;
int FineSmootherOrder = 16;
RealD CoarseSmootherShift = 0.1;
int CoarseSmootherNstep = 4;
RealD CoarseSolverTol = 0.03;
int CoarseSolverOrder = 200;
RealD L3Tol = 2.5e-1;
int L3MaxIt = 50;
int L3Nstep = 50;
RealD OuterTol = 1.0e-8;
int OuterMmax = 8;
int OuterNstep = 8;
int Nrhs = 12;
RealD mass = 0.00078;
void ParseEnvironment(void)
{
if(getenv("MASS")) mass = atof(getenv("MASS"));
if(getenv("FineSmootherShift")) FineSmootherShift = atof(getenv("FineSmootherShift"));
if(getenv("FineSmootherOrder")) FineSmootherOrder = atoi(getenv("FineSmootherOrder"));
if(getenv("CoarseSmootherShift"))CoarseSmootherShift= atof(getenv("CoarseSmootherShift"));
if(getenv("CoarseSmootherNstep"))CoarseSmootherNstep= atoi(getenv("CoarseSmootherNstep"));
if(getenv("CoarseSolverTol")) CoarseSolverTol = atof(getenv("CoarseSolverTol"));
if(getenv("CoarseSolverOrder")) CoarseSolverOrder = atoi(getenv("CoarseSolverOrder"));
if(getenv("L3_TOL")) L3Tol = atof(getenv("L3_TOL"));
if(getenv("L3_MAXIT")) L3MaxIt = atoi(getenv("L3_MAXIT"));
if(getenv("L3_NSTEP")) L3Nstep = atoi(getenv("L3_NSTEP"));
if(getenv("OuterTol")) OuterTol = atof(getenv("OuterTol"));
if(getenv("OuterMmax")) OuterMmax = atoi(getenv("OuterMmax"));
if(getenv("OuterNstep")) OuterNstep = atoi(getenv("OuterNstep"));
if(getenv("NRHS")) Nrhs = atoi(getenv("NRHS"));
std::cout << GridLogMessage << "PARAM: MASS " << mass << std::endl;
std::cout << GridLogMessage << "PARAM: NRHS " << Nrhs << std::endl;
std::cout << GridLogMessage << "PARAM: FineSmootherShift " << FineSmootherShift << std::endl;
std::cout << GridLogMessage << "PARAM: FineSmootherOrder " << FineSmootherOrder << std::endl;
std::cout << GridLogMessage << "PARAM: CoarseSmootherShift" << CoarseSmootherShift<< std::endl;
std::cout << GridLogMessage << "PARAM: CoarseSmootherNstep" << CoarseSmootherNstep<< std::endl;
std::cout << GridLogMessage << "PARAM: CoarseSolverTol " << CoarseSolverTol << std::endl;
std::cout << GridLogMessage << "PARAM: CoarseSolverOrder " << CoarseSolverOrder << std::endl;
std::cout << GridLogMessage << "PARAM: L3_TOL " << L3Tol << std::endl;
std::cout << GridLogMessage << "PARAM: OuterMmax " << OuterMmax << std::endl;
std::cout << GridLogMessage << "PARAM: OuterNstep " << OuterNstep << 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), and shifted variant for smoothers.
//////////////////////////////////////////////////////////////////////
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); }
};
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); }
};
// Generic shift wrapper (for the coarse-level smoother on the 6D mrhs coarse operator).
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); }
};
int main (int argc, char ** argv)
{
Grid_init(&argc,&argv);
ParseEnvironment();
const int Ls=24; RealD M5=1.8, b=1.5, c=0.5;
const int nbasis=60; const int nrhs=Nrhs;
GRID_ASSERT(nrhs % vComplex::Nsimd() == 0);
std::vector<int> lat_size {48,48,48,96};
GridCartesian * UGrid = SpaceTimeGrid::makeFourDimGrid(lat_size, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
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({2,2,2,2});
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;
// Level 2 blocking (default 2,2,3,3) -- matches Example_pvdagm_3level_SVDdefl
Coordinate cclatt = clatt;
Coordinate Block2({2,2,3,3});
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;
GridCartesian *Coarse4d = SpaceTimeGrid::makeFourDimGrid(clatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
GridCartesian *Coarse5d = SpaceTimeGrid::makeFiveDimGrid(1,Coarse4d);
GridCartesian *CoarseCoarse4d = SpaceTimeGrid::makeFourDimGrid(cclatt, GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
GridCartesian *CoarseCoarse5d = SpaceTimeGrid::makeFiveDimGrid(1,CoarseCoarse4d);
// 6D mrhs grids: rhs is dim 0, SIMD across rhs (pattern: Test_general_coarse_hdcg_phys48.cc)
Coordinate mpi=GridDefaultMpi();
Coordinate rhMpi ({1,1,mpi[0],mpi[1],mpi[2],mpi[3]});
Coordinate rhSimd({vComplex::Nsimd(),1,1,1,1,1});
Coordinate rhLatt ({nrhs,1,clatt[0], clatt[1], clatt[2], clatt[3]});
Coordinate rhLatt2({nrhs,1,cclatt[0],cclatt[1],cclatt[2],cclatt[3]});
GridCartesian *CoarseMrhs = new GridCartesian(rhLatt, rhSimd,rhMpi);
GridCartesian *CoarseCoarseMrhs = new GridCartesian(rhLatt2,rhSimd,rhMpi);
GridParallelRNG RNG5(FGrid); RNG5.SeedFixedIntegers({5,6,7,8});
LatticeGaugeField Umu(UGrid);
std::cout << GridLogMessage << "Reading gauge field" << std::endl;
FieldMetaData header;
std::string file("/ccs/home/poare/ckpoint_lat.1000");
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);
typedef PVdagMLinearOperator<MobiusFermionD,LatticeFermionD> PVdagM_t;
typedef ShiftedPVdagMLinearOperator<MobiusFermionD,LatticeFermionD> ShiftedPVdagM_t;
// Level 1 tensor types
typedef DeprecatedGeneralCoarsenedMatrix<vSpinColourVector,vTComplex,nbasis> LittleDiracOperator;
typedef DeprecatedMultiGeneralCoarsenedMatrix<vSpinColourVector,vTComplex,nbasis> MrhsLittleDiracOperator;
typedef LittleDiracOperator::CoarseVector CoarseVector;
typedef Aggregation<vSpinColourVector,vTComplex,nbasis> Subspace;
// Level 2 tensor types (coarsening deepens the nest by one iScalar -- see CLAUDE.md)
typedef CoarseVector::vector_object CoarseSiteObj;
typedef iScalar<vTComplex> vTTComplex;
typedef DeprecatedGeneralCoarsenedMatrix<CoarseSiteObj,vTTComplex,nbasis> LittleDiracOperatorL2;
typedef DeprecatedMultiGeneralCoarsenedMatrix<CoarseSiteObj,vTTComplex,nbasis> MrhsLittleDiracOperatorL2;
typedef LittleDiracOperatorL2::CoarseVector CoarseCoarseVector;
typedef Aggregation<CoarseSiteObj,vTTComplex,nbasis> SubspaceL2;
PVdagM_t PVdagM(Ddwf,Dpv);
ShiftedPVdagM_t ShiftedPVdagM(FineSmootherShift,Ddwf,Dpv);
NextToNearestStencilGeometry5D geom (Coarse5d);
NextToNearestStencilGeometry5D geom2(CoarseCoarse5d); // 33-point at L2->L3, matching SVDdefl
//////////////////////////////////////////////////////////////////////
// Subspace: load RAW (no Orthogonalise!), or generate.
//////////////////////////////////////////////////////////////////////
std::string subspace_file = "/lustre/orion/phy157/proj-shared/phy157_dwf/paboyle/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 of the fine null vectors BEFORE CoarsenOperator block-orthonormalises in place.
std::vector<LatticeFermionD> rawNull(nbasis,FGrid);
for(int k=0;k<nbasis;k++) rawNull[k]=AggregatesGCR.subspace[k];
//////////////////////////////////////////////////////////////////////
// Coarsen L1->L2 and L2->L3 with SINGLE-RHS machinery, import into the mrhs
// operators via CopyMatrix. The single-RHS L1->L2 coarse operator must stay
// alive to be the "fine" operator for the L2->L3 coarsening, so BOTH single-RHS
// ops (and their padded _A) live in one scope and free together. [MEMORY: this
// is the setup peak -- L1->L2 padded _A (~large at 2^4) + L2->L3 padded _A.]
//////////////////////////////////////////////////////////////////////
MrhsLittleDiracOperator mrhsLittleDiracOpPV(geom, CoarseMrhs);
MrhsLittleDiracOperatorL2 mrhsLittleDiracOpL2(geom2, CoarseCoarseMrhs);
MultiRHSBlockProject<LatticeFermionD> MrhsProjector;
MultiRHSBlockProject<CoarseVector> MrhsProjectorL2;
{
// --- L1->L2 single-RHS coarse operator (kept alive for the L2->L3 coarsening) ---
LittleDiracOperator LittleDiracOpPV(geom,FGrid,Coarse5d);
LittleDiracOpPV.CoarsenOperator(PVdagM, AggregatesGCR); // orthonormalises AggregatesGCR.subspace in place
mrhsLittleDiracOpPV.CopyMatrix(LittleDiracOpPV);
MrhsProjector.Allocate(nbasis,FGrid,Coarse5d);
MrhsProjector.ImportBasis(AggregatesGCR.subspace); // orthonormalised, matches the coarse op
NonHermitianLinearOperator<LittleDiracOperator,CoarseVector> LinOpCoarse(LittleDiracOpPV);
// --- psi_coarse = P^dag (RAW fine null) -> Galerkin images, NOT e_k ---
std::vector<CoarseVector> psi_coarse(nbasis,Coarse5d);
for(int k=0;k<nbasis;k++) AggregatesGCR.ProjectToSubspace(psi_coarse[k], rawNull[k]);
rawNull.clear(); rawNull.shrink_to_fit();
{
RealD s2=0.0;
for(int i=0;i<nbasis;i++) for(int j=0;j<nbasis;j++){
ComplexD sij=TensorRemove(innerProduct(psi_coarse[i],psi_coarse[j]));
ComplexD d=sij-(i==j?ComplexD(1.0):ComplexD(0.0)); s2+=real(d)*real(d)+imag(d)*imag(d);
}
std::cout<<GridLogMessage<<"GUARD: ||<psi_coarse|psi_coarse> - I||_F = "<<std::sqrt(s2)
<<" (~0.23 good; ~sqrt(N_coarse)="<<std::sqrt((double)Coarse5d->gSites())<<" = e_k leak)"<<std::endl;
}
// --- L2->L3 single-RHS coarsening (coarsen the single-RHS LinOpCoarse) ---
SubspaceL2 AggregatesL2(CoarseCoarse5d,Coarse5d,cb);
for(int k=0;k<nbasis;k++) AggregatesL2.subspace[k]=psi_coarse[k];
LittleDiracOperatorL2 LittleDiracOpL2(geom2,Coarse5d,CoarseCoarse5d);
LittleDiracOpL2.CoarsenOperator(LinOpCoarse, AggregatesL2);
mrhsLittleDiracOpL2.CopyMatrix(LittleDiracOpL2);
MrhsProjectorL2.Allocate(nbasis,Coarse5d,CoarseCoarse5d);
MrhsProjectorL2.ImportBasis(AggregatesL2.subspace); // orthonormalised by CoarsenOperator
// --- guard psi_cc (RAW psi_coarse; AggregatesL2 holds a separate orthonormalised copy) ---
{
std::vector<CoarseCoarseVector> psi_cc(nbasis,CoarseCoarse5d);
for(int k=0;k<nbasis;k++) AggregatesL2.ProjectToSubspace(psi_cc[k], psi_coarse[k]);
RealD s2=0.0;
for(int i=0;i<nbasis;i++) for(int j=0;j<nbasis;j++){
ComplexD sij=TensorRemove(innerProduct(psi_cc[i],psi_cc[j]));
ComplexD d=sij-(i==j?ComplexD(1.0):ComplexD(0.0)); s2+=real(d)*real(d)+imag(d)*imag(d);
}
std::cout<<GridLogMessage<<"GUARD: ||<psi_cc|psi_cc> - I||_F = "<<std::sqrt(s2)
<<" (~0.23 good; ~sqrt(N_cc)="<<std::sqrt((double)CoarseCoarse5d->gSites())<<" = e_k leak)"<<std::endl;
}
} // both single-RHS ops + padded _A + AggregatesL2 + psi_coarse freed here
NonHermitianLinearOperator<MrhsLittleDiracOperator,CoarseVector> mrhsLinOpCoarse(mrhsLittleDiracOpPV);
NonHermitianLinearOperator<MrhsLittleDiracOperatorL2,CoarseCoarseVector> mrhsLinOpCC(mrhsLittleDiracOpL2);
//////////////////////////////////////////////////////////////////////
// Solvers, innermost first.
//////////////////////////////////////////////////////////////////////
TrivialPrecon<CoarseVector> simpleC;
TrivialPrecon<CoarseCoarseVector> simpleCC;
TrivialPrecon<LatticeFermionD> simple_fine;
// L3 (coarse-coarse) solve: PGCR on the 6D cc operator
PrecGeneralisedConjugateResidualNonHermitian<CoarseCoarseVector>
L3PGCR(L3Tol,L3MaxIt,mrhsLinOpCC,simpleCC,L3Nstep,L3Nstep);
L3PGCR.Level(3);
L3PGCR.Name("CCouter");
L3PGCR.SetZeroGuess(1); // caller zeroes CCsol
// L2 coarse smoother: shifted 6D coarse op, fixed nstep
ShiftedLinearOperator<CoarseVector> ShiftedMrhsCoarse(CoarseSmootherShift, mrhsLinOpCoarse);
PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>
CoarseSmootherGCR(0.01,1,ShiftedMrhsCoarse,simpleC,CoarseSmootherNstep,CoarseSmootherNstep);
CoarseSmootherGCR.Level(2);
CoarseSmootherGCR.Name("Csmoother");
CoarseSmootherGCR.SetZeroGuess(1); // caller zeroes vec2
// L2->L3 V-cycle preconditioner (operates on 6D coarse field)
MrhsCoarseThreeLevelPrec<CoarseVector,CoarseCoarseVector>
L2to3Precon(mrhsLinOpCoarse, CoarseSmootherGCR, MrhsProjectorL2, L3PGCR,
Coarse5d, CoarseCoarse5d, CoarseCoarseMrhs, nrhs);
// L2 coarse solve: PGCR on 6D coarse op, preconditioned by the L2->L3 V-cycle
PrecGeneralisedConjugateResidualNonHermitian<CoarseVector>
L2PGCR(CoarseSolverTol, CoarseSolverOrder/16, mrhsLinOpCoarse, L2to3Precon, 16, 16);
L2PGCR.Level(2);
L2PGCR.Name("Couter");
L2PGCR.SetZeroGuess(1); // caller zeroes CsolMrhs
// Fine smoother (per-rhs, looped in the L1->L2 V-cycle)
PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD>
SmootherGCR(0.0,1,ShiftedPVdagM,simple_fine,FineSmootherOrder,FineSmootherOrder);
SmootherGCR.Level(1);
SmootherGCR.Name("Fsmoother");
SmootherGCR.SetZeroGuess(1); // caller zeroes vec2[r]
// L1->L2 V-cycle (fine); its coarse solve is the three-level L2PGCR
typedef PrecGeneralisedConjugateResidualNonHermitian<LatticeFermionD> FineSmoother_t;
MrhsTwoLevelMG<LatticeFermionD,CoarseVector,FineSmoother_t>
ThreeLevelPrecon(PVdagM, SmootherGCR, MrhsProjector, L2PGCR, Coarse5d, CoarseMrhs);
// Outer mrhs solve
MrhsPGCRNonHermitian<LatticeFermionD>
L1PGCR(OuterTol,1000,PVdagM,ThreeLevelPrecon,OuterMmax,OuterNstep);
L1PGCR.Level(1);
L1PGCR.Name("Fouter");
L1PGCR.SetZeroGuess(1); // sol[r]=Zero() at source setup
//////////////////////////////////////////////////////////////////////
// Sources and solve
//////////////////////////////////////////////////////////////////////
std::vector<LatticeFermionD> src(nrhs,FGrid), sol(nrhs,FGrid);
for(int r=0;r<nrhs;r++){ gaussian(RNG5,src[r]); sol[r]=Zero(); }
std::cout << GridLogMessage << "**********************************************" << std::endl;
std::cout << GridLogMessage << " MultiRHS THREE-level solve: " << nrhs << " RHS " << std::endl;
std::cout << GridLogMessage << "**********************************************" << std::endl;
GridStopWatch w; w.Start();
L1PGCR(src,sol);
w.Stop();
std::cout << GridLogMessage << "MultiRHS 3-level solve total " << w.Elapsed()
<< " (per RHS: " << w.useconds()/1.0e6/nrhs << " s)" << std::endl;
{ LatticeFermionD Ax(FGrid); RealD worst=0.0;
for(int r=0;r<nrhs;r++){ PVdagM.Op(sol[r],Ax); Ax=Ax-src[r];
RealD rn=std::sqrt(norm2(Ax)/norm2(src[r]));
std::cout << GridLogMessage << "FINAL: rhs["<<r<<"] true residual = " << rn << std::endl;
worst=std::max(worst,rn); }
std::cout << GridLogMessage << "FINAL: worst-case residual = " << worst << std::endl;
}
std::cout << GridLogMessage << "Done" << std::endl;
Grid_finalize();
return 0;
}