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Grid/lib/qcd/action/gauge/WilsonGaugeAction.h
2018-01-14 22:50:35 +00:00

95 lines
3.0 KiB
C++

/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./lib/qcd/action/gauge/WilsonGaugeAction.h
Copyright (C) 2015
Author: Azusa Yamaguchi <ayamaguc@staffmail.ed.ac.uk>
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
Author: neo <cossu@post.kek.jp>
Author: paboyle <paboyle@ph.ed.ac.uk>
Author: Guido Cossu <guido.cossu@ed.ac.uk>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
See the full license in the file "LICENSE" in the top level distribution
directory
*************************************************************************************/
/* END LEGAL */
#ifndef QCD_WILSON_GAUGE_ACTION_H
#define QCD_WILSON_GAUGE_ACTION_H
NAMESPACE_BEGIN(Grid);
////////////////////////////////////////////////////////////////////////
// Wilson Gauge Action .. should I template the Nc etc..
////////////////////////////////////////////////////////////////////////
template <class Gimpl>
class WilsonGaugeAction : public Action<typename Gimpl::GaugeField> {
public:
INHERIT_GIMPL_TYPES(Gimpl);
/////////////////////////// constructors
explicit WilsonGaugeAction(RealD beta_):beta(beta_){};
virtual std::string action_name() {return "WilsonGaugeAction";}
virtual std::string LogParameters(){
std::stringstream sstream;
sstream << GridLogMessage << "[WilsonGaugeAction] Beta: " << beta << std::endl;
return sstream.str();
}
virtual void refresh(const GaugeField &U,
GridParallelRNG &pRNG){}; // noop as no pseudoferms
virtual RealD S(const GaugeField &U) {
RealD plaq = WilsonLoops<Gimpl>::avgPlaquette(U);
RealD vol = U._grid->gSites();
RealD action = beta * (1.0 - plaq) * (Nd * (Nd - 1.0)) * vol * 0.5;
return action;
};
virtual void deriv(const GaugeField &U, GaugeField &dSdU) {
// not optimal implementation FIXME
// extend Ta to include Lorentz indexes
RealD factor = 0.5 * beta / RealD(Nc);
//GaugeLinkField Umu(U._grid);
GaugeLinkField dSdU_mu(U._grid);
for (int mu = 0; mu < Nd; mu++) {
//Umu = PeekIndex<LorentzIndex>(U, mu);
// Staple in direction mu
//WilsonLoops<Gimpl>::Staple(dSdU_mu, U, mu);
//dSdU_mu = Ta(Umu * dSdU_mu) * factor;
WilsonLoops<Gimpl>::StapleMult(dSdU_mu, U, mu);
dSdU_mu = Ta(dSdU_mu) * factor;
PokeIndex<LorentzIndex>(dSdU, dSdU_mu, mu);
}
}
private:
RealD beta;
};
NAMESPACE_END(Grid);
#endif