mirror of
https://github.com/paboyle/Grid.git
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19da647e3c
(The above required exposing the gauge implementation to the HMC class through the Integrator class) Made the random shift optional (default on) through a parameter in HMCparameters Modified ConjugateBC::CshiftLink such that it supports any shift in -L < shift < L rather than just +-1 Added a tester for the BC-respecting Cshift Fixed a missing system header include in SSE4 intrinsics wrapper Fixed sumD_cpu for single-prec types performing an incorrect conversion to a single-prec data type at the end, that fails to compile on some systems
239 lines
8.0 KiB
C++
239 lines
8.0 KiB
C++
/*************************************************************************************
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grid` physics library, www.github.com/paboyle/Grid
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Copyright (C) 2015
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Author: Azusa Yamaguchi <ayamaguc@staffmail.ed.ac.uk>
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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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//#include <Grid/Grid.h>
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#ifndef GRID_QCD_GAUGE_FIX_H
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#define GRID_QCD_GAUGE_FIX_H
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NAMESPACE_BEGIN(Grid);
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template <class Gimpl>
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class FourierAcceleratedGaugeFixer : public Gimpl {
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public:
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INHERIT_GIMPL_TYPES(Gimpl);
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typedef typename Gimpl::GaugeLinkField GaugeMat;
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typedef typename Gimpl::GaugeField GaugeLorentz;
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//A_\mu(x) = -i Ta(U_\mu(x) ) where Ta(U) = 1/2( U - U^dag ) - 1/2N tr(U - U^dag) is the traceless antihermitian part. This is an O(A^3) approximation to the logarithm of U
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static void GaugeLinkToLieAlgebraField(const GaugeMat &U, GaugeMat &A) {
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Complex cmi(0.0,-1.0);
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A = Ta(U) * cmi;
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}
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//The derivative of the Lie algebra field
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static void DmuAmu(const std::vector<GaugeMat> &U, GaugeMat &dmuAmu,int orthog) {
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GridBase* grid = U[0].Grid();
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GaugeMat Ax(grid);
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GaugeMat Axm1(grid);
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GaugeMat Utmp(grid);
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dmuAmu=Zero();
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for(int mu=0;mu<Nd;mu++){
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if ( mu != orthog ) {
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//Rather than define functionality to work out how the BCs apply to A_\mu we simply use the BC-aware Cshift to the gauge links and compute A_\mu(x) and A_\mu(x-1) separately
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//Ax = A_\mu(x)
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GaugeLinkToLieAlgebraField(U[mu], Ax);
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//Axm1 = A_\mu(x_\mu-1)
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Utmp = Gimpl::CshiftLink(U[mu], mu, -1);
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GaugeLinkToLieAlgebraField(Utmp, Axm1);
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//Derivative
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dmuAmu = dmuAmu + Ax - Axm1;
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}
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}
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}
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//Fix the gauge field Umu
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//0 < alpha < 1 is related to the step size, cf https://arxiv.org/pdf/1405.5812.pdf
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static void SteepestDescentGaugeFix(GaugeLorentz &Umu,Real alpha,int maxiter,Real Omega_tol, Real Phi_tol,bool Fourier=false,int orthog=-1,bool err_on_no_converge=true) {
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GridBase *grid = Umu.Grid();
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GaugeMat xform(grid);
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SteepestDescentGaugeFix(Umu,xform,alpha,maxiter,Omega_tol,Phi_tol,Fourier,orthog,err_on_no_converge);
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}
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static void SteepestDescentGaugeFix(GaugeLorentz &Umu,GaugeMat &xform,Real alpha,int maxiter,Real Omega_tol, Real Phi_tol,bool Fourier=false,int orthog=-1,bool err_on_no_converge=true) {
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//Fix the gauge field Umu and also return the gauge transformation from the original gauge field, xform
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GridBase *grid = Umu.Grid();
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Real org_plaq =WilsonLoops<Gimpl>::avgPlaquette(Umu);
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Real org_link_trace=WilsonLoops<Gimpl>::linkTrace(Umu);
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Real old_trace = org_link_trace;
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Real trG;
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xform=1.0;
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std::vector<GaugeMat> U(Nd,grid);
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GaugeMat dmuAmu(grid);
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{
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Real plaq =WilsonLoops<Gimpl>::avgPlaquette(Umu);
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Real link_trace=WilsonLoops<Gimpl>::linkTrace(Umu);
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if( (orthog>=0) && (orthog<Nd) ){
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std::cout << GridLogMessage << " Gauge fixing to Coulomb gauge time="<<orthog<< " plaq= "<<plaq<<" link trace = "<<link_trace<< std::endl;
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} else {
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std::cout << GridLogMessage << " Gauge fixing to Landau gauge plaq= "<<plaq<<" link trace = "<<link_trace<< std::endl;
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}
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}
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for(int i=0;i<maxiter;i++){
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for(int mu=0;mu<Nd;mu++) U[mu]= PeekIndex<LorentzIndex>(Umu,mu);
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if ( Fourier==false ) {
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trG = SteepestDescentStep(U,xform,alpha,dmuAmu,orthog);
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} else {
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trG = FourierAccelSteepestDescentStep(U,xform,alpha,dmuAmu,orthog);
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}
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// std::cout << GridLogMessage << "trG "<< trG<< std::endl;
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// std::cout << GridLogMessage << "xform "<< norm2(xform)<< std::endl;
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// std::cout << GridLogMessage << "dmuAmu "<< norm2(dmuAmu)<< std::endl;
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for(int mu=0;mu<Nd;mu++) PokeIndex<LorentzIndex>(Umu,U[mu],mu);
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// Monitor progress and convergence test
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// infrequently to minimise cost overhead
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if ( i %20 == 0 ) {
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Real plaq =WilsonLoops<Gimpl>::avgPlaquette(Umu);
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Real link_trace=WilsonLoops<Gimpl>::linkTrace(Umu);
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if (Fourier)
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std::cout << GridLogMessage << "Fourier Iteration "<<i<< " plaq= "<<plaq<< " dmuAmu " << norm2(dmuAmu)<< std::endl;
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else
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std::cout << GridLogMessage << " Iteration "<<i<< " plaq= "<<plaq<< " dmuAmu " << norm2(dmuAmu)<< std::endl;
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Real Phi = 1.0 - old_trace / link_trace ;
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Real Omega= 1.0 - trG;
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std::cout << GridLogMessage << " Iteration "<<i<< " Phi= "<<Phi<< " Omega= " << Omega<< " trG " << trG <<std::endl;
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if ( (Omega < Omega_tol) && ( ::fabs(Phi) < Phi_tol) ) {
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std::cout << GridLogMessage << "Converged ! "<<std::endl;
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return;
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}
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old_trace = link_trace;
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}
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}
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std::cout << GridLogError << "Gauge fixing did not converge in " << maxiter << " iterations." << std::endl;
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if (err_on_no_converge)
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assert(0 && "Gauge fixing did not converge within the specified number of iterations");
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};
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static Real SteepestDescentStep(std::vector<GaugeMat> &U,GaugeMat &xform, Real alpha, GaugeMat & dmuAmu,int orthog) {
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GridBase *grid = U[0].Grid();
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GaugeMat g(grid);
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ExpiAlphaDmuAmu(U,g,alpha,dmuAmu,orthog);
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Real vol = grid->gSites();
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Real trG = TensorRemove(sum(trace(g))).real()/vol/Nc;
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xform = g*xform ;
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SU<Nc>::GaugeTransform<Gimpl>(U,g);
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return trG;
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}
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static Real FourierAccelSteepestDescentStep(std::vector<GaugeMat> &U,GaugeMat &xform, Real alpha, GaugeMat & dmuAmu,int orthog) {
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GridBase *grid = U[0].Grid();
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Real vol = grid->gSites();
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FFT theFFT((GridCartesian *)grid);
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LatticeComplex Fp(grid);
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LatticeComplex psq(grid); psq=Zero();
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LatticeComplex pmu(grid);
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LatticeComplex one(grid); one = Complex(1.0,0.0);
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GaugeMat g(grid);
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GaugeMat dmuAmu_p(grid);
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DmuAmu(U,dmuAmu,orthog);
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std::vector<int> mask(Nd,1);
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for(int mu=0;mu<Nd;mu++) if (mu==orthog) mask[mu]=0;
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theFFT.FFT_dim_mask(dmuAmu_p,dmuAmu,mask,FFT::forward);
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//////////////////////////////////
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// Work out Fp = psq_max/ psq...
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// Avoid singularities in Fp
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//////////////////////////////////
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Coordinate latt_size = grid->GlobalDimensions();
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Coordinate coor(grid->_ndimension,0);
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for(int mu=0;mu<Nd;mu++) {
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if ( mu != orthog ) {
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Real TwoPiL = M_PI * 2.0/ latt_size[mu];
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LatticeCoordinate(pmu,mu);
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pmu = TwoPiL * pmu ;
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psq = psq + 4.0*sin(pmu*0.5)*sin(pmu*0.5);
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}
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}
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Complex psqMax(16.0);
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Fp = psqMax*one/psq;
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pokeSite(TComplex(16.0),Fp,coor);
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if( (orthog>=0) && (orthog<Nd) ){
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for(int t=0;t<grid->GlobalDimensions()[orthog];t++){
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coor[orthog]=t;
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pokeSite(TComplex(16.0),Fp,coor);
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}
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}
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dmuAmu_p = dmuAmu_p * Fp;
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theFFT.FFT_dim_mask(dmuAmu,dmuAmu_p,mask,FFT::backward);
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GaugeMat ciadmam(grid);
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Complex cialpha(0.0,-alpha);
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ciadmam = dmuAmu*cialpha;
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SU<Nc>::taExp(ciadmam,g);
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Real trG = TensorRemove(sum(trace(g))).real()/vol/Nc;
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xform = g*xform ;
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SU<Nc>::GaugeTransform<Gimpl>(U,g);
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return trG;
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}
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static void ExpiAlphaDmuAmu(const std::vector<GaugeMat> &U,GaugeMat &g, Real alpha, GaugeMat &dmuAmu,int orthog) {
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GridBase *grid = g.Grid();
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Complex cialpha(0.0,-alpha);
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GaugeMat ciadmam(grid);
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DmuAmu(U,dmuAmu,orthog);
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ciadmam = dmuAmu*cialpha;
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SU<Nc>::taExp(ciadmam,g);
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}
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};
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NAMESPACE_END(Grid);
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#endif
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