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135 lines
3.9 KiB
C++
135 lines
3.9 KiB
C++
#ifndef QCD_PSEUDOFERMION_TWO_FLAVOUR_RATIO_H
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#define QCD_PSEUDOFERMION_TWO_FLAVOUR_RATIO_H
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namespace Grid{
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namespace QCD{
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///////////////////////////////////////
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// Two flavour ratio
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///////////////////////////////////////
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template<class Impl>
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class TwoFlavourRatioPseudoFermionAction : public Action<typename Impl::GaugeField> {
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public:
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INHERIT_IMPL_TYPES(Impl);
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private:
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FermionOperator<Impl> & NumOp;// the basic operator
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FermionOperator<Impl> & DenOp;// the basic operator
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OperatorFunction<FermionField> &DerivativeSolver;
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OperatorFunction<FermionField> &ActionSolver;
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FermionField Phi; // the pseudo fermion field for this trajectory
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public:
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TwoFlavourRatioPseudoFermionAction(FermionOperator<Impl> &_NumOp,
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FermionOperator<Impl> &_DenOp,
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OperatorFunction<FermionField> & DS,
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OperatorFunction<FermionField> & AS
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) : NumOp(_NumOp), DenOp(_DenOp), DerivativeSolver(DS), ActionSolver(AS), Phi(_NumOp.FermionGrid()) {};
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virtual void init(const GaugeField &U, GridParallelRNG& pRNG) {
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// P(phi) = e^{- phi^dag V (MdagM)^-1 Vdag phi}
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//
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// NumOp == V
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// DenOp == M
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//
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// Take phi = Vdag^{-1} Mdag eta ; eta = Mdag^{-1} Vdag Phi
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//
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// P(eta) = e^{- eta^dag eta}
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//
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// e^{x^2/2 sig^2} => sig^2 = 0.5.
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//
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// So eta should be of width sig = 1/sqrt(2) and must multiply by 0.707....
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//
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RealD scale = std::sqrt(0.5);
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FermionField eta(NumOp.FermionGrid());
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FermionField tmp(NumOp.FermionGrid());
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gaussian(pRNG,eta);
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NumOp.ImportGauge(U);
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DenOp.ImportGauge(U);
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// Note: this hard codes normal equations type solvers; alternate implementation needed for
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// non-herm style solvers.
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MdagMLinearOperator<FermionOperator<Impl> ,FermionField> MdagMOp(NumOp);
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DenOp.Mdag(eta,Phi); // Mdag eta
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ActionSolver(MdagMOp,Phi,tmp); // (VdagV)^-1 Mdag eta = V^-1 Vdag^-1 Mdag eta
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NumOp.M(tmp,Phi); // Vdag^-1 Mdag eta
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Phi=Phi*scale;
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};
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//////////////////////////////////////////////////////
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// S = phi^dag V (Mdag M)^-1 Vdag phi
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//////////////////////////////////////////////////////
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virtual RealD S(const GaugeField &U) {
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NumOp.ImportGauge(U);
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DenOp.ImportGauge(U);
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FermionField X(NumOp.FermionGrid());
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FermionField Y(NumOp.FermionGrid());
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MdagMLinearOperator<FermionOperator<Impl> ,FermionField> MdagMOp(DenOp);
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X=zero;
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NumOp.Mdag(Phi,Y); // Y= Vdag phi
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ActionSolver(MdagMOp,Y,X); // X= (MdagM)^-1 Vdag phi
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DenOp.M(X,Y); // Y= Mdag^-1 Vdag phi
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RealD action = norm2(Y);
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return action;
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};
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//////////////////////////////////////////////////////
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// dS/du = phi^dag dV (Mdag M)^-1 V^dag phi
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// - phi^dag V (Mdag M)^-1 [ Mdag dM + dMdag M ] (Mdag M)^-1 V^dag phi
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// + phi^dag V (Mdag M)^-1 dV^dag phi
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//////////////////////////////////////////////////////
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virtual void deriv(const GaugeField &U,GaugeField & dSdU) {
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NumOp.ImportGauge(U);
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DenOp.ImportGauge(U);
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MdagMLinearOperator<FermionOperator<Impl> ,FermionField> MdagMOp(DenOp);
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FermionField X(NumOp.FermionGrid());
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FermionField Y(NumOp.FermionGrid());
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GaugeField force(NumOp.GaugeGrid());
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X=zero;
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//Y=Vdag phi
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//X = (Mdag M)^-1 V^dag phi
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//Y = (Mdag)^-1 V^dag phi
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NumOp.Mdag(Phi,Y); // Y= Vdag phi
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DerivativeSolver(MdagMOp,Y,X); // X= (MdagM)^-1 Vdag phi
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DenOp.M(X,Y); // Y= Mdag^-1 Vdag phi
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// phi^dag V (Mdag M)^-1 dV^dag phi
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NumOp.MDeriv(force , X, Phi, DaggerYes ); dSdU=force;
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// phi^dag dV (Mdag M)^-1 V^dag phi
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NumOp.MDeriv(force , Phi, X ,DaggerNo ); dSdU=dSdU+force;
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// - phi^dag V (Mdag M)^-1 Mdag dM (Mdag M)^-1 V^dag phi
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// - phi^dag V (Mdag M)^-1 dMdag M (Mdag M)^-1 V^dag phi
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DenOp.MDeriv(force,Y,X,DaggerNo); dSdU=dSdU-force;
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DenOp.MDeriv(force,X,Y,DaggerYes); dSdU=dSdU-force;
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dSdU = - Ta(dSdU);
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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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