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new utils for baryons

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ferben 2019-07-18 14:24:16 +01:00
parent 5a62ebe7b1
commit feb029fb66
1 changed files with 155 additions and 0 deletions
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Grid/qcd/utils/BaryonUtils.h Normal file
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#pragma once
//#include <Grid/Hadrons/Global.hpp>
#include <Grid/Eigen/unsupported/CXX11/Tensor>
namespace Grid {
namespace QCD {
#undef DELTA_F_EQ_2
template <typename FImpl>
class BaryonUtils
{
public:
typedef typename FImpl::ComplexField ComplexField;
typedef typename FImpl::FermionField FermionField;
typedef typename FImpl::PropagatorField PropagatorField;
typedef typename FImpl::SiteSpinor vobj;
typedef typename vobj::scalar_object sobj;
typedef typename vobj::scalar_type scalar_type;
typedef typename vobj::vector_type vector_type;
static void ContractBaryons(const PropagatorField &q1,
const PropagatorField &q2,
const PropagatorField &q3,
ComplexField &baryon_corr);
};
template<class FImpl>
void BaryonUtils<FImpl>::ContractBaryons(const PropagatorField &q1,
const PropagatorField &q2,
const PropagatorField &q3,
ComplexField &baryon_corr)
{
assert(gamma0.size()==gamma1.size());
int Ng = gamma0.size();
GridBase *grid = q1._grid;
// C = i gamma_2 gamma_4 => C gamma_5 = - i gamma_1 gamma_3
Gamma GammaA(Gamma::Algebra::Identity); //Still hardcoded 1
Gamma GammaB(Gamma::Algebra::SigmaXZ); //Still hardcoded Cg5
Gamma g4(Gamma::Algebra::GammaT); //needed for parity P_\pm = 0.5*(1 \pm \gamma_4)
std::vector<std::vector<int>> epsilon = {{0,1,2},{1,2,0},{2,0,1},{0,2,1},{2,1,0},{1,0,2}};
std::vector<int> epsilon_sgn = {1,1,1,-1,-1,-1};
char left[] = "uud";
char right[] = "uud";
std::vector<int> wick_contraction = {0,0,0,0,0,0};
for (int ie=0; ie < 6 ; ie++)
if (left[0] == right[epsilon[ie][0]] && left[1] == right[epsilon[ie][1]] && left[2] == right[epsilon[ie][2]])
wick_contraction[ie]=1;
int parity = 1;
parallel_for(int ss=0;ss<grid->oSites();ss++){
typedef typename ComplexField::vector_object vobj;
auto D1 = q1._odata[ss];
auto D2 = q2._odata[ss];
auto D3 = q3._odata[ss];
auto gD1a = GammaA * GammaA * D1;
auto gD1b = GammaA * g4 * GammaA * D1;
auto pD1 = 0.5* (gD1a + (double)parity * dD1b);
auto gD3 = GammaB * D3;
vobj result=zero;
for (int ie_src=0; ie_src < 6 ; ie_src++){
int a_src = epsilon[ie_src][0]; //a
int b_src = epsilon[ie_src][1]; //b
int c_src = epsilon[ie_src][2]; //c
for (int ie_snk=0; ie_snk < 6 ; ie_snk++){
int a_snk = epsilon[ie_snk][0]; //a'
int b_snk = epsilon[ie_snk][1]; //b'
int c_snk = epsilon[ie_snk][2]; //c'
//This is the \delta_{123}^{123} part
if (wick_contraction[0]){
auto D2g = D2 * GammaB;
for (int alpha_snk=0; alpha_snk<Ns; alpha_snk++){
for (int beta_src=0; beta_src<Ns; beta_src++){
for (int gamma_src=0; gamma_src<Ns; gamma_src++){
result()()() += epsilon_sgn[ie_src] * epsilon_sgn[ie_snk] * pD1()(gamma_src,gamma_src)(c_snk,c_src)*D2g()(alpha_snk,beta_src)(a_snk,a_src)*gD3()(alpha_snk,beta_src)(b_snk,b_src);
}}}
}
//This is the \delta_{123}^{231} part
if (wick_contraction[1]){
auto pD1g = pD1 * GammaB;
for (int alpha_snk=0; alpha_snk<Ns; alpha_snk++){
for (int beta_src=0; beta_src<Ns; beta_src++){
for (int gamma_src=0; gamma_src<Ns; gamma_src++){
result()()() += epsilon_sgn[ie_src] * epsilon_sgn[ie_snk] * pD1g()(gamma_src,beta_src)(c_snk,a_src)*D2()(alpha_snk,beta_src)(a_snk,b_src)*gD3()(alpha_snk,gamma_src)(b_snk,c_src);
}}}
}
//This is the \delta_{123}^{312} part
if (wick_contraction[2]){
auto gD3g = gD3 * GammaB;
for (int alpha_snk=0; alpha_snk<Ns; alpha_snk++){
for (int beta_src=0; beta_src<Ns; beta_src++){
for (int gamma_src=0; gamma_src<Ns; gamma_src++){
result()()() += epsilon_sgn[ie_src] * epsilon_sgn[ie_snk] * pD1()(gamma_src,beta_src)(c_snk,b_src)*D2()(alpha_snk,gamma_src)(a_snk,c_src)*gD3g()(alpha_snk,beta_src)(b_snk,a_src);
}}}
}
//This is the \delta_{123}^{132} part
if (wick_contraction[3]){
auto gD3g = gD3 * GammaB;
for (int alpha_snk=0; alpha_snk<Ns; alpha_snk++){
for (int beta_src=0; beta_src<Ns; beta_src++){
for (int gamma_src=0; gamma_src<Ns; gamma_src++){
result()()() -= epsilon_sgn[ie_src] * epsilon_sgn[ie_snk] * pD1()(gamma_src,gamma_src)(c_snk,c_src)*D2()(alpha_snk,beta_src)(a_snk,b_src)*gD3()(alpha_snk,beta_src)(b_snk,a_src);
}}}
}
//This is the \delta_{123}^{321} part
if (wick_contraction[4]){
auto D2g = D2 * GammaB;
for (int alpha_snk=0; alpha_snk<Ns; alpha_snk++){
for (int beta_src=0; beta_src<Ns; beta_src++){
for (int gamma_src=0; gamma_src<Ns; gamma_src++){
result()()() -= epsilon_sgn[ie_src] * epsilon_sgn[ie_snk] * pD1()(gamma_src,beta_src)(c_snk,b_src)*D2g()(alpha_snk,beta_src)(a_snk,a_src)*gD3()(alpha_snk,gamma_src)(b_snk,c_src);
}}}
}
//This is the \delta_{123}^{213} part
if (wick_contraction[5]){
auto pD1g = pD1 * GammaB;
for (int alpha_snk=0; alpha_snk<Ns; alpha_snk++){
for (int beta_src=0; beta_src<Ns; beta_src++){
for (int gamma_src=0; gamma_src<Ns; gamma_src++){
result()()() -= epsilon_sgn[ie_src] * epsilon_sgn[ie_snk] * pD1g()(gamma_src,beta_src)(c_snk,a_src)*D2()(alpha_snk,gamma_src)(a_snk,c_src)*gD3()(alpha_snk,beta_src)(b_snk,b_src);
}}}
}
if (ie_src==0 && ie_snk==0){
baryon_corr._odata[ss] = result;
} else {
baryon_corr._odata[ss] += result;
}
}
}
} //end loop over lattice sites
}
}}