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Grid/tests/core/Test_fft_matt.cc
2023-03-21 16:05:46 -04:00

245 lines
7.7 KiB
C++

/*************************************************************************************
Gamma::Algebra Gmu [] = {
Gamma::Algebra::GammaX,
Gamma::Algebra::GammaY,
Gamma::Algebra::GammaZ,
Gamma::Algebra::GammaT,
Gamma::Algebra::Gamma5
};
int main (int argc, char ** argv)
{
Grid_init(&argc,&argv);
int threads = GridThread::GetThreads();
std::cout<<GridLogMessage << "Grid is setup to use "<<threads<<" threads"<<std::endl;
Coordinate latt_size = GridDefaultLatt();
Coordinate simd_layout = GridDefaultSimd(Nd,vComplexD::Nsimd());
Coordinate mpi_layout = GridDefaultMpi();
int vol = 1;
for(int d=0;d<latt_size.size();d++){
vol = vol * latt_size[d];
}
GridCartesian GRID(latt_size,simd_layout,mpi_layout);
GridRedBlackCartesian RBGRID(&GRID);
LatticeComplexD coor(&GRID);
ComplexD ci(0.0,1.0);
std::vector<int> seeds({1,2,3,4});
GridSerialRNG sRNG; sRNG.SeedFixedIntegers(seeds); // naughty seeding
GridParallelRNG pRNG(&GRID);
pRNG.SeedFixedIntegers(seeds);
LatticeGaugeFieldD Umu(&GRID);
SU<Nc>::ColdConfiguration(pRNG,Umu); // Unit gauge
////////////////////////////////////////////////////
// Wilson test
////////////////////////////////////////////////////
{
LatticeFermionD src(&GRID); gaussian(pRNG,src);
LatticeFermionD src_p(&GRID);
LatticeFermionD tmp(&GRID);
LatticeFermionD ref(&GRID);
LatticeFermionD result(&GRID);
RealD mass=0.1;
WilsonFermionD Dw(Umu,GRID,RBGRID,mass);
Dw.M(src,ref);
std::cout << "Norm src "<<norm2(src)<<std::endl;
std::cout << "Norm Dw x src "<<norm2(ref)<<std::endl;
{
FFT theFFT(&GRID);
////////////////
// operator in Fourier space
////////////////
tmp =ref;
theFFT.FFT_all_dim(result,tmp,FFT::forward);
std::cout<<"FFT[ Dw x src ] "<< norm2(result)<<std::endl;
tmp = src;
theFFT.FFT_all_dim(src_p,tmp,FFT::forward);
std::cout<<"FFT[ src ] "<< norm2(src_p)<<std::endl;
/////////////////////////////////////////////////////////////////
// work out the predicted FT from Fourier
/////////////////////////////////////////////////////////////////
auto FGrid = &GRID;
LatticeFermionD Kinetic(FGrid); Kinetic = Zero();
LatticeComplexD kmu(FGrid);
LatticeInteger scoor(FGrid);
LatticeComplexD sk (FGrid); sk = Zero();
LatticeComplexD sk2(FGrid); sk2= Zero();
LatticeComplexD W(FGrid); W= Zero();
LatticeComplexD one(FGrid); one =ComplexD(1.0,0.0);
ComplexD ci(0.0,1.0);
for(int mu=0;mu<Nd;mu++) {
RealD TwoPiL = M_PI * 2.0/ latt_size[mu];
LatticeCoordinate(kmu,mu);
kmu = TwoPiL * kmu;
sk2 = sk2 + 2.0*sin(kmu*0.5)*sin(kmu*0.5);
sk = sk + sin(kmu) *sin(kmu);
// -1/2 Dw -> 1/2 gmu (eip - emip) = i sinp gmu
Kinetic = Kinetic + sin(kmu)*ci*(Gamma(Gmu[mu])*src_p);
}
W = mass + sk2;
Kinetic = Kinetic + W * src_p;
std::cout<<"Momentum space src "<< norm2(src_p)<<std::endl;
std::cout<<"Momentum space Dw x src "<< norm2(Kinetic)<<std::endl;
std::cout<<"FT[Coordinate space Dw] "<< norm2(result)<<std::endl;
result = result - Kinetic;
std::cout<<"diff "<< norm2(result)<<std::endl;
}
std::cout << " =======================================" <<std::endl;
std::cout << " Checking FourierFreePropagator x Dw = 1" <<std::endl;
std::cout << " =======================================" <<std::endl;
std::cout << "Dw src = " <<norm2(src)<<std::endl;
std::cout << "Dw tmp = " <<norm2(tmp)<<std::endl;
Dw.M(src,tmp);
Dw.FreePropagator(tmp,ref,mass);
std::cout << "Dw ref = " <<norm2(ref)<<std::endl;
ref = ref - src;
std::cout << "Dw ref-src = " <<norm2(ref)<<std::endl;
}
////////////////////////////////////////////////////
// Wilson prop
////////////////////////////////////////////////////
{
std::cout<<"****************************************"<<std::endl;
std::cout << "Wilson Mom space 4d propagator \n";
std::cout<<"****************************************"<<std::endl;
LatticeFermionD src(&GRID); gaussian(pRNG,src);
LatticeFermionD tmp(&GRID);
LatticeFermionD ref(&GRID);
LatticeFermionD diff(&GRID);
src=Zero();
Coordinate point(4,0); // 0,0,0,0
SpinColourVectorD ferm;
ferm=Zero();
ferm()(0)(0) = ComplexD(1.0);
pokeSite(ferm,src,point);
RealD mass=0.1;
WilsonFermionD Dw(Umu,GRID,RBGRID,mass);
// Momentum space prop
std::cout << " Solving by FFT and Feynman rules" <<std::endl;
Dw.FreePropagator(src,ref,mass) ;
Gamma G5(Gamma::Algebra::Gamma5);
LatticeFermionD result(&GRID);
const int sdir=0;
////////////////////////////////////////////////////////////////////////
// Conjugate gradient on normal equations system
////////////////////////////////////////////////////////////////////////
std::cout << " Solving by Conjugate Gradient (CGNE)" <<std::endl;
Dw.Mdag(src,tmp);
src=tmp;
MdagMLinearOperator<WilsonFermionD,LatticeFermionD> HermOp(Dw);
ConjugateGradient<LatticeFermionD> CG(1.0e-10,10000);
CG(HermOp,src,result);
////////////////////////////////////////////////////////////////////////
std::cout << " Taking difference" <<std::endl;
std::cout << "Dw result "<<norm2(result)<<std::endl;
std::cout << "Dw ref "<<norm2(ref)<<std::endl;
diff = ref - result;
std::cout << "result - ref "<<norm2(diff)<<std::endl;
DumpSliceNorm("Slice Norm Solution ",result,Nd-1);
}
////////////////////////////////////////////////////
//Gauge invariance test
////////////////////////////////////////////////////
{
std::cout<<"****************************************"<<std::endl;
std::cout << "Gauge invariance test \n";
std::cout<<"****************************************"<<std::endl;
LatticeGaugeField U_GT(&GRID); // Gauge transformed field
LatticeColourMatrix g(&GRID); // local Gauge xform matrix
U_GT = Umu;
// Make a random xform to teh gauge field
SU<Nc>::RandomGaugeTransform(pRNG,U_GT,g); // Unit gauge
LatticeFermionD src(&GRID);
LatticeFermionD tmp(&GRID);
LatticeFermionD ref(&GRID);
LatticeFermionD diff(&GRID);
// could loop over colors
src=Zero();
Coordinate point(4,0); // 0,0,0,0
SpinColourVectorD ferm;
ferm=Zero();
ferm()(0)(0) = ComplexD(1.0);
pokeSite(ferm,src,point);
RealD mass=0.1;
WilsonFermionD Dw(U_GT,GRID,RBGRID,mass);
// Momentum space prop
std::cout << " Solving by FFT and Feynman rules" <<std::endl;
Dw.FreePropagator(src,ref,mass) ;
Gamma G5(Gamma::Algebra::Gamma5);
LatticeFermionD result(&GRID);
const int sdir=0;
////////////////////////////////////////////////////////////////////////
// Conjugate gradient on normal equations system
////////////////////////////////////////////////////////////////////////
std::cout << " Solving by Conjugate Gradient (CGNE)" <<std::endl;
Dw.Mdag(src,tmp);
src=tmp;
MdagMLinearOperator<WilsonFermionD,LatticeFermionD> HermOp(Dw);
ConjugateGradient<LatticeFermionD> CG(1.0e-10,10000);
CG(HermOp,src,result);
////////////////////////////////////////////////////////////////////////
std::cout << " Taking difference" <<std::endl;
std::cout << "Dw result "<<norm2(result)<<std::endl;
std::cout << "Dw ref "<<norm2(ref)<<std::endl;
diff = ref - result;
std::cout << "result - ref "<<norm2(diff)<<std::endl;
DumpSliceNorm("Slice Norm Solution ",result,Nd-1);
}
Grid_finalize();
}