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198 lines
7.2 KiB
C++
198 lines
7.2 KiB
C++
/*************************************************************************************
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Grid physics library, www.github.com/paboyle/Grid
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Source file: Hadrons/Modules/MContraction/Nucleon.hpp
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Copyright (C) 2015-2019
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Author: Antonin Portelli <antonin.portelli@me.com>
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Author: Felix Erben <felix.erben@ed.ac.uk>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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See the full license in the file "LICENSE" in the top level distribution directory
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*************************************************************************************/
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/* END LEGAL */
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#ifndef Hadrons_MContraction_Nucleon_hpp_
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#define Hadrons_MContraction_Nucleon_hpp_
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#include <Hadrons/Global.hpp>
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#include <Hadrons/Module.hpp>
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#include <Hadrons/ModuleFactory.hpp>
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BEGIN_HADRONS_NAMESPACE
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/******************************************************************************
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* Nucleon *
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******************************************************************************/
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BEGIN_MODULE_NAMESPACE(MContraction)
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class NucleonPar: Serializable
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{
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public:
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GRID_SERIALIZABLE_CLASS_MEMBERS(NucleonPar,
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std::string, q1,
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std::string, q2,
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std::string, q3,
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std::string, output);
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};
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template <typename FImpl1, typename FImpl2, typename FImpl3>
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class TNucleon: public Module<NucleonPar>
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{
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public:
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FERM_TYPE_ALIASES(FImpl1, 1);
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FERM_TYPE_ALIASES(FImpl2, 2);
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FERM_TYPE_ALIASES(FImpl3, 3);
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class Result: Serializable
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{
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public:
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GRID_SERIALIZABLE_CLASS_MEMBERS(Result,
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std::vector<Complex>, corr);
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};
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public:
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// constructor
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TNucleon(const std::string name);
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// destructor
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virtual ~TNucleon(void) {};
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// dependency relation
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virtual std::vector<std::string> getInput(void);
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virtual std::vector<std::string> getOutput(void);
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protected:
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// setup
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virtual void setup(void);
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// execution
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virtual void execute(void);
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};
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MODULE_REGISTER_TMP(Nucleon, ARG(TNucleon<FIMPL, FIMPL, FIMPL>), MContraction);
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/******************************************************************************
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* TNucleon implementation *
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******************************************************************************/
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// constructor /////////////////////////////////////////////////////////////////
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template <typename FImpl1, typename FImpl2, typename FImpl3>
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TNucleon<FImpl1, FImpl2, FImpl3>::TNucleon(const std::string name)
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: Module<NucleonPar>(name)
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{}
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// dependencies/products ///////////////////////////////////////////////////////
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template <typename FImpl1, typename FImpl2, typename FImpl3>
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std::vector<std::string> TNucleon<FImpl1, FImpl2, FImpl3>::getInput(void)
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{
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std::vector<std::string> input = {par().q1, par().q2, par().q3};
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return input;
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}
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template <typename FImpl1, typename FImpl2, typename FImpl3>
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std::vector<std::string> TNucleon<FImpl1, FImpl2, FImpl3>::getOutput(void)
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{
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std::vector<std::string> out = {};
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return out;
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}
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// setup ///////////////////////////////////////////////////////////////////////
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template <typename FImpl1, typename FImpl2, typename FImpl3>
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void TNucleon<FImpl1, FImpl2, FImpl3>::setup(void)
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{
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envTmpLat(LatticeComplex, "c");
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envTmpLat(LatticeComplex, "diquark");
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}
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// execution ///////////////////////////////////////////////////////////////////
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template <typename FImpl1, typename FImpl2, typename FImpl3>
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void TNucleon<FImpl1, FImpl2, FImpl3>::execute(void)
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{
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LOG(Message) << "Computing nucleon contractions '" << getName() << "' using"
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<< " quarks '" << par().q1 << "', '" << par().q2 << "', and '"
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<< par().q3 << "'" << std::endl;
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auto &q1 = envGet(PropagatorField1, par().q1);
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auto &q2 = envGet(PropagatorField2, par().q2);
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auto &q3 = envGet(PropagatorField3, par().q2);
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envGetTmp(LatticeComplex, c);
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envGetTmp(LatticeComplex, diquark);
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Result result;
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int nt = env().getDim(Tp);
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result.corr.resize(nt);
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std::vector<TComplex> buf;
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// C = i gamma_2 gamma_4 => C gamma_5 = - i gamma_1 gamma_3
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Gamma Cg5(Gamma::Algebra::SigmaXZ);
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Gamma g4(Gamma::Algebra::GammaT); //needed for parity P_\pm = 0.5*(1 \pm \gamma_4)
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std::vector<std::vector<int>> epsilon = {{0,1,2},{1,2,0},{2,0,1},{0,2,1},{2,1,0},{1,0,2}};
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std::vector<int> epsilon_sgn = {1,1,1,-1,-1,-1};
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// This is the \delta_{123}^{123} part
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for (int ie_src=0; ie_src < 6 ; ie_src++){
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int c1_src = epsilon[ie_src][0]; //a
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int c2_src = epsilon[ie_src][1]; //b
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int c3_src = epsilon[ie_src][2]; //c
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for (int ie_snk=0; ie_snk < 6 ; ie_snk++){
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int c1_snk = epsilon[ie_snk][0]; //a'
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int c2_snk = epsilon[ie_snk][1]; //b'
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int c3_snk = epsilon[ie_snk][2]; //c'
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auto Dcc = peekColour(q1,c1_snk,c1_src); //D_{gamma' gamma}
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auto Daa = peekColour(q2,c2_snk,c2_src); //D_{alpha' alpha}
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//auto test = transposeSpin(Daa); //Does not work...
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auto Dbb = peekColour(q3,c3_snk,c3_src); //D_{beta' beta}
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diquark = trace(Cg5 * Daa * Cg5 * Dbb); //Daa transposed????
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//diquark = q2()()(c2,1) * Cg5 * q3()()(c3,2); //Why does this not work??
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auto temp = Dcc * diquark;
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auto g4_temp = g4 * temp;
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int parity = 1;
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c += epsilon_sgn[ie_src] * epsilon_sgn[ie_snk] * 0.5 * (double)parity * trace(temp + g4_temp);
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}
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}
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// This is the \delta_{123}^{213} part
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for (int ie_src=0; ie_src < 6 ; ie_src++){
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int c1_src = epsilon[ie_src][0]; //a
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int c2_src = epsilon[ie_src][1]; //b
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int c3_src = epsilon[ie_src][2]; //c
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for (int ie_snk=0; ie_snk < 6 ; ie_snk++){
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int c1_snk = epsilon[ie_snk][0]; //a'
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int c2_snk = epsilon[ie_snk][1]; //b'
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int c3_snk = epsilon[ie_snk][2]; //c'
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auto Dca = peekColour(q1,c1_snk,c2_src); //D_{gamma' alpha}
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auto Dac = peekColour(q2,c2_snk,c1_src); //D_{alpha' gamma}
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auto Dbb = peekColour(q3,c3_snk,c3_src); //D_{beta' beta}
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auto temp = Dca * Cg5 * Dbb * Cg5 * Dac; //(Dbb*Cg5) transposed???
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auto g4_temp = g4 * temp;
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int parity = 1;
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c -= epsilon_sgn[ie_src] * epsilon_sgn[ie_snk] * 0.5 * (double)parity * trace(temp + g4_temp);
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}
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}
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sliceSum(c,buf,Tp);
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for (unsigned int t = 0; t < buf.size(); ++t)
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{
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result.corr[t] = TensorRemove(buf[t]);
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}
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saveResult(par().output, "baryon", result);
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}
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END_MODULE_NAMESPACE
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END_HADRONS_NAMESPACE
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#endif // Hadrons_MContraction_Nucleon_hpp_
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