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f7d61b8b81
http://arxiv.org/pdf/hep-lat/0610075.pdf plaq and rect regress plausibly over 100 trajectories and under HMC with average plaq and rectangle coming out ok.
99 lines
2.8 KiB
C++
99 lines
2.8 KiB
C++
#ifndef QCD_PLAQ_PLUS_RECTANGLE_ACTION_H
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#define QCD_PLAQ_PLUS_RECTANGLE_ACTION_H
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namespace Grid{
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namespace QCD{
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////////////////////////////////////////////////////////////////////////
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// PlaqPlusRectangleActoin
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////////////////////////////////////////////////////////////////////////
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template<class GaugeField>
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class PlaqPlusRectangleAction : public Action<GaugeField> {
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public:
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typedef LorentzScalar<GaugeField> GaugeLinkField;
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private:
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RealD c_plaq;
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RealD c_rect;
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public:
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PlaqPlusRectangleAction(RealD b,RealD c): c_plaq(b),c_rect(c){};
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virtual void refresh(const GaugeField &U, GridParallelRNG& pRNG) {}; // noop as no pseudoferms
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virtual RealD S(const GaugeField &U) {
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RealD vol = U._grid->gSites();
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RealD plaq = WilsonLoops<GaugeField>::avgPlaquette(U);
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RealD rect = WilsonLoops<GaugeField>::avgRectangle(U);
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RealD action=c_plaq*(1.0 -plaq)*(Nd*(Nd-1.0))*vol*0.5
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+c_rect*(1.0 -rect)*(Nd*(Nd-1.0))*vol;
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return action;
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};
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virtual void deriv(const GaugeField &U,GaugeField & dSdU) {
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//extend Ta to include Lorentz indexes
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RealD factor_p = c_plaq/RealD(Nc)*0.5;
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RealD factor_r = c_rect/RealD(Nc)*0.5;
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GaugeLinkField Umu(U._grid);
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GaugeLinkField dSdU_mu(U._grid);
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GaugeLinkField staple(U._grid);
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for (int mu=0; mu < Nd; mu++){
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Umu = PeekIndex<LorentzIndex>(U,mu);
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// Staple in direction mu
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WilsonLoops<GaugeField>::Staple(staple,U,mu);
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dSdU_mu = Ta(Umu*staple)*factor_p;
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WilsonLoops<GaugeField>::RectStaple(staple,U,mu);
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dSdU_mu = dSdU_mu + Ta(Umu*staple)*factor_r;
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PokeIndex<LorentzIndex>(dSdU, dSdU_mu, mu);
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}
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};
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};
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// Convenience for common physically defined cases.
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//
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// RBC c1 parameterisation is not really RBC but don't have good
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// reference and we are happy to change name if prior use of this plaq coeff
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// parameterisation is made known to us.
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template<class GaugeField>
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class RBCGaugeAction : public PlaqPlusRectangleAction<GaugeField> {
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public:
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RBCGaugeAction(RealD beta,RealD c1) : PlaqPlusRectangleAction<GaugeField>(beta*(1.0-8.0*c1), beta*c1) {
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};
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};
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template<class GaugeField>
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class IwasakiGaugeAction : public RBCGaugeAction<GaugeField> {
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public:
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IwasakiGaugeAction(RealD beta) : RBCGaugeAction<GaugeField>(beta,-0.331) {
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};
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};
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template<class GaugeField>
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class SymanzikGaugeAction : public RBCGaugeAction<GaugeField> {
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public:
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SymanzikGaugeAction(RealD beta) : RBCGaugeAction<GaugeField>(beta,-1.0/12.0) {
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};
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};
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template<class GaugeField>
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class DBW2GaugeAction : public RBCGaugeAction<GaugeField> {
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public:
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DBW2GaugeAction(RealD beta) : RBCGaugeAction<GaugeField>(beta,-1.4067) {
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};
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};
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}
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}
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#endif
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