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76 lines
2.4 KiB
C++
76 lines
2.4 KiB
C++
/*************************************************************************************
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Grid physics library, www.github.com/paboyle/Grid
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Source file: ./lib/qcd/action/gauge/shGordonAction.h
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Copyright (C) 2018
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Author: Guido Cossu <guido.cossu@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
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directory
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*************************************************************************************/
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/* END LEGAL */
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#ifndef SHGORDON_ACTION_H
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#define SHGORDON_ACTION_H
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namespace Grid {
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template <class Impl>
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class shGordonAction : public QCD::Action<typename Impl::Field> {
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public:
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INHERIT_FIELD_TYPES(Impl);
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private:
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RealD mass_square;
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RealD g;
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public:
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shGordonAction(RealD ms, RealD g) : mass_square(ms), g(g) {}
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virtual std::string LogParameters() {
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std::stringstream sstream;
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sstream << GridLogMessage << "[shGordonAction] g : " << g << std::endl;
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sstream << GridLogMessage << "[shGordonAction] mass_square : " << mass_square << std::endl;
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return sstream.str();
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}
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virtual std::string action_name() {return "shGordonAction";}
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virtual void refresh(const Field &U, GridParallelRNG &pRNG) {} // noop as no pseudoferms
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virtual RealD S(const Field &phi) {
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return 0.5*ScalarObs<Impl>::sumphider(phi) - 0.5*mass_square/(g*g)*sum(trace(exp(g*phi) + exp(-g*phi))) ;
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};
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virtual void deriv(const Field &phi,
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Field &force) {
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Field tmp(phi._grid);
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tmp = zero;
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for (int mu = 0; mu < QCD::Nd; mu++) tmp += Cshift(phi, mu, 1) - Cshift(phi, mu, -1);
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force+= 0.5*tmp - 0.5*mass_square/g*(exp(g*phi) - exp(-g*phi));
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}
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};
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} // namespace Grid
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#endif // SHGORDON_ACTION_H
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