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Grid/examples/Example_Mobius_spectrum.cc
2021-08-30 21:15:39 -04:00

315 lines
9.2 KiB
C++

/*
* Warning: This code illustrative only: not well tested, and not meant for production use
* without regression / tests being applied
*/
#include <Grid/Grid.h>
using namespace std;
using namespace Grid;
template<class Gimpl,class Field> class CovariantLaplacianCshift : public SparseMatrixBase<Field>
{
public:
INHERIT_GIMPL_TYPES(Gimpl);
GridBase *grid;
GaugeField U;
CovariantLaplacianCshift(GaugeField &_U) :
grid(_U.Grid()),
U(_U) { };
virtual GridBase *Grid(void) { return grid; };
virtual void M (const Field &in, Field &out)
{
out=Zero();
for(int mu=0;mu<Nd-1;mu++) {
GaugeLinkField Umu = PeekIndex<LorentzIndex>(U, mu); // NB: Inefficent
out = out - Gimpl::CovShiftForward(Umu,mu,in);
out = out - Gimpl::CovShiftBackward(Umu,mu,in);
out = out + 2.0*in;
}
};
virtual void Mdag (const Field &in, Field &out) { M(in,out);}; // Laplacian is hermitian
virtual void Mdiag (const Field &in, Field &out) {assert(0);}; // Unimplemented need only for multigrid
virtual void Mdir (const Field &in, Field &out,int dir, int disp){assert(0);}; // Unimplemented need only for multigrid
virtual void MdirAll (const Field &in, std::vector<Field> &out) {assert(0);}; // Unimplemented need only for multigrid
};
void MakePhase(Coordinate mom,LatticeComplex &phase)
{
GridBase *grid = phase.Grid();
auto latt_size = grid->GlobalDimensions();
ComplexD ci(0.0,1.0);
phase=Zero();
LatticeComplex coor(phase.Grid());
for(int mu=0;mu<Nd;mu++){
RealD TwoPiL = M_PI * 2.0/ latt_size[mu];
LatticeCoordinate(coor,mu);
phase = phase + (TwoPiL * mom[mu]) * coor;
}
phase = exp(phase*ci);
}
void PointSource(Coordinate &coor,LatticePropagator &source)
{
// Coordinate coor({0,0,0,0});
source=Zero();
SpinColourMatrix kronecker; kronecker=1.0;
pokeSite(kronecker,source,coor);
}
void Z2WallSource(GridParallelRNG &RNG,int tslice,LatticePropagator &source)
{
GridBase *grid = source.Grid();
LatticeComplex noise(grid);
LatticeComplex zz(grid); zz=Zero();
LatticeInteger t(grid);
RealD nrm=1.0/sqrt(2);
bernoulli(RNG, noise); // 0,1 50:50
noise = (2.*noise - Complex(1,1))*nrm;
LatticeCoordinate(t,Tdir);
noise = where(t==Integer(tslice), noise, zz);
source = 1.0;
source = source*noise;
std::cout << " Z2 wall " << norm2(source) << std::endl;
}
template<class Field>
void GaussianSmear(LatticeGaugeField &U,Field &unsmeared,Field &smeared)
{
typedef CovariantLaplacianCshift <PeriodicGimplR,Field> Laplacian_t;
Laplacian_t Laplacian(U);
Integer Iterations = 40;
Real width = 2.0;
Real coeff = (width*width) / Real(4*Iterations);
Field tmp(U.Grid());
smeared=unsmeared;
// chi = (1-p^2/2N)^N kronecker
for(int n = 0; n < Iterations; ++n) {
Laplacian.M(smeared,tmp);
smeared = smeared - coeff*tmp;
std::cout << " smear iter " << n<<" " <<norm2(smeared)<<std::endl;
}
}
void GaussianSource(Coordinate &site,LatticeGaugeField &U,LatticePropagator &source)
{
LatticePropagator tmp(source.Grid());
PointSource(site,source);
std::cout << " GaussianSource Kronecker "<< norm2(source)<<std::endl;
tmp = source;
GaussianSmear(U,tmp,source);
std::cout << " GaussianSource Smeared "<< norm2(source)<<std::endl;
}
void GaussianWallSource(GridParallelRNG &RNG,int tslice,LatticeGaugeField &U,LatticePropagator &source)
{
Z2WallSource(RNG,tslice,source);
auto tmp = source;
GaussianSmear(U,tmp,source);
}
void SequentialSource(int tslice,Coordinate &mom,LatticePropagator &spectator,LatticePropagator &source)
{
assert(mom.size()==Nd);
assert(mom[Tdir] == 0);
GridBase * grid = spectator.Grid();
LatticeInteger ts(grid);
LatticeCoordinate(ts,Tdir);
source = Zero();
source = where(ts==Integer(tslice),spectator,source); // Stick in a slice of the spectator, zero everywhere else
LatticeComplex phase(grid);
MakePhase(mom,phase);
source = source *phase;
}
template<class Action>
void Solve(Action &D,LatticePropagator &source,LatticePropagator &propagator)
{
GridBase *UGrid = D.GaugeGrid();
GridBase *FGrid = D.FermionGrid();
LatticeFermion src4 (UGrid);
LatticeFermion src5 (FGrid);
LatticeFermion result5(FGrid);
LatticeFermion result4(UGrid);
ConjugateGradient<LatticeFermion> CG(1.0e-8,100000);
SchurRedBlackDiagMooeeSolve<LatticeFermion> schur(CG);
ZeroGuesser<LatticeFermion> ZG; // Could be a DeflatedGuesser if have eigenvectors
for(int s=0;s<Nd;s++){
for(int c=0;c<Nc;c++){
PropToFerm<Action>(src4,source,s,c);
D.ImportPhysicalFermionSource(src4,src5);
result5=Zero();
schur(D,src5,result5,ZG);
std::cout<<GridLogMessage
<<"spin "<<s<<" color "<<c
<<" norm2(src5d) " <<norm2(src5)
<<" norm2(result5d) "<<norm2(result5)<<std::endl;
D.ExportPhysicalFermionSolution(result5,result4);
FermToProp<Action>(propagator,result4,s,c);
}
}
}
class MesonFile: Serializable {
public:
GRID_SERIALIZABLE_CLASS_MEMBERS(MesonFile, std::vector<std::vector<Complex> >, data);
};
void MesonTrace(std::string file,LatticePropagator &q1,LatticePropagator &q2,LatticeComplex &phase)
{
const int nchannel=4;
Gamma::Algebra Gammas[nchannel][2] = {
{Gamma::Algebra::Gamma5 ,Gamma::Algebra::Gamma5},
{Gamma::Algebra::GammaTGamma5,Gamma::Algebra::GammaTGamma5},
{Gamma::Algebra::GammaTGamma5,Gamma::Algebra::Gamma5},
{Gamma::Algebra::Gamma5 ,Gamma::Algebra::GammaTGamma5}
};
Gamma G5(Gamma::Algebra::Gamma5);
LatticeComplex meson_CF(q1.Grid());
MesonFile MF;
for(int ch=0;ch<nchannel;ch++){
Gamma Gsrc(Gammas[ch][0]);
Gamma Gsnk(Gammas[ch][1]);
meson_CF = trace(G5*adj(q1)*G5*Gsnk*q2*adj(Gsrc));
std::vector<TComplex> meson_T;
sliceSum(meson_CF,meson_T, Tdir);
int nt=meson_T.size();
std::vector<Complex> corr(nt);
for(int t=0;t<nt;t++){
corr[t] = TensorRemove(meson_T[t]); // Yes this is ugly, not figured a work around
std::cout << " channel "<<ch<<" t "<<t<<" " <<corr[t]<<std::endl;
}
MF.data.push_back(corr);
}
{
XmlWriter WR(file);
write(WR,"MesonFile",MF);
}
}
int main (int argc, char ** argv)
{
const int Ls=8;
Grid_init(&argc,&argv);
// Double precision grids
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);
//////////////////////////////////////////////////////////////////////
// You can manage seeds however you like.
// Recommend SeedUniqueString.
//////////////////////////////////////////////////////////////////////
std::vector<int> seeds4({1,2,3,4});
GridParallelRNG RNG4(UGrid); RNG4.SeedFixedIntegers(seeds4);
LatticeGaugeField Umu(UGrid);
std::string config;
if( argc > 1 && argv[1][0] != '-' )
{
std::cout<<GridLogMessage <<"Loading configuration from "<<argv[1]<<std::endl;
FieldMetaData header;
NerscIO::readConfiguration(Umu, header, argv[1]);
config=argv[1];
}
else
{
std::cout<<GridLogMessage <<"Using hot configuration"<<std::endl;
SU<Nc>::ColdConfiguration(Umu);
// SU<Nc>::HotConfiguration(RNG4,Umu);
config="HotConfig";
}
std::vector<RealD> masses({ 0.03,0.04,0.45} ); // u/d, s, c ??
int nmass = masses.size();
std::vector<MobiusFermionR *> FermActs;
std::cout<<GridLogMessage <<"======================"<<std::endl;
std::cout<<GridLogMessage <<"MobiusFermion action as Scaled Shamir kernel"<<std::endl;
std::cout<<GridLogMessage <<"======================"<<std::endl;
for(auto mass: masses) {
RealD M5=1.0;
RealD b=1.5;// Scale factor b+c=2, b-c=1
RealD c=0.5;
FermActs.push_back(new MobiusFermionR(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,mass,M5,b,c));
}
LatticePropagator point_source(UGrid);
LatticePropagator wall_source(UGrid);
LatticePropagator gaussian_source(UGrid);
Coordinate Origin({0,0,0,0});
PointSource (Origin,point_source);
Z2WallSource (RNG4,0,wall_source);
GaussianSource(Origin,Umu,gaussian_source);
std::vector<LatticePropagator> PointProps(nmass,UGrid);
std::vector<LatticePropagator> GaussProps(nmass,UGrid);
std::vector<LatticePropagator> Z2Props (nmass,UGrid);
for(int m=0;m<nmass;m++) {
Solve(*FermActs[m],point_source ,PointProps[m]);
Solve(*FermActs[m],gaussian_source,GaussProps[m]);
Solve(*FermActs[m],wall_source ,Z2Props[m]);
}
LatticeComplex phase(UGrid);
Coordinate mom({0,0,0,0});
MakePhase(mom,phase);
for(int m1=0 ;m1<nmass;m1++) {
for(int m2=m1;m2<nmass;m2++) {
std::stringstream ssp,ssg,ssz;
ssp<<config<< "_m" << m1 << "_m"<< m2 << "_point_meson.xml";
ssg<<config<< "_m" << m1 << "_m"<< m2 << "_smeared_meson.xml";
ssz<<config<< "_m" << m1 << "_m"<< m2 << "_wall_meson.xml";
MesonTrace(ssp.str(),PointProps[m1],PointProps[m2],phase);
MesonTrace(ssg.str(),GaussProps[m1],GaussProps[m2],phase);
MesonTrace(ssz.str(),Z2Props[m1],Z2Props[m2],phase);
}}
Grid_finalize();
}