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127 lines
3.5 KiB
C++
127 lines
3.5 KiB
C++
/*************************************************************************************
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Grid physics library, www.github.com/paboyle/Grid
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Source file: ./lib/qcd/action/gauge/Photon.h
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Copyright (C) 2015
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Author: Peter Boyle <paboyle@ph.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 QCD_PHOTON_ACTION_H
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#define QCD_PHOTON_ACTION_H
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namespace Grid{
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namespace QCD{
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template<class Gimpl>
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class Photon {
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public:
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INHERIT_GIMPL_TYPES(Gimpl);
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enum PhotonType { FEYNMAN_L, FEYNMAN_TL };
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PhotonType GaugeBC;
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Photon(PhotonType _GaugeBC) : GaugeBC(_GaugeBC){};
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void FreePropagator (const GaugeField &in,GaugeField &out) {
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FFT theFFT((GridCartesian *) in._grid);
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GaugeField in_k(in._grid);
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GaugeField prop_k(in._grid);
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theFFT.FFT_all_dim(in_k,in,FFT::forward);
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MomentumSpacePropagator(prop_k,in_k);
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theFFT.FFT_all_dim(out,prop_k,FFT::backward);
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}
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void MomentumSpacePropagator(GaugeField &out,const GaugeField &in) {
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if ( GaugeBC == FEYNMAN_L ) {
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FeynmanGaugeMomentumSpacePropagator_L(out,in);
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} else if ( GaugeBC == FEYNMAN_TL ) {
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FeynmanGaugeMomentumSpacePropagator_TL(out,in);
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} else { // No coulomb yet
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assert(0);
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}
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}
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void FeynmanGaugeMomentumSpacePropagator_L(GaugeField &out, const GaugeField &in) {
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FeynmanGaugeMomentumSpacePropagator_TL(out,in);
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GridBase *grid = out._grid;
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LatticeInteger coor(grid);
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GaugeField zz(grid); zz=zero;
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// xyzt
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for(int d = 0; d < grid->_ndimension-1;d++){
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LatticeCoordinate(coor,d);
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out = where(coor==Integer(0),zz,out);
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}
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}
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void FeynmanGaugeMomentumSpacePropagator_TL(GaugeField &out, const GaugeField &in) {
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// what type LatticeComplex
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GridBase *grid = out._grid;
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int nd = grid->_ndimension;
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typedef typename GaugeField::vector_type vector_type;
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typedef typename GaugeField::scalar_type ScalComplex;
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typedef Lattice<iSinglet<vector_type> > LatComplex;
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std::vector<int> latt_size = grid->_fdimensions;
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LatComplex denom(grid); denom= zero;
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LatComplex one(grid); one = ScalComplex(1.0,0.0);
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LatComplex kmu(grid);
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ScalComplex ci(0.0,1.0);
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// momphase = n * 2pi / L
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for(int mu=0;mu<Nd;mu++) {
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LatticeCoordinate(kmu,mu);
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RealD TwoPiL = M_PI * 2.0/ latt_size[mu];
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kmu = TwoPiL * kmu ;
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denom = denom + 4.0*sin(kmu*0.5)*sin(kmu*0.5); // Wilson term
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}
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std::vector<int> zero_mode(nd,0);
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TComplexD Tone = ComplexD(1.0,0.0);
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TComplexD Tzero= ComplexD(0.0,0.0);
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pokeSite(Tone,denom,zero_mode);
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denom= one/denom;
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pokeSite(Tzero,denom,zero_mode);
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out = zero;
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out = in*denom;
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};
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};
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}}
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#endif
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