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Optimised version of rectangle term staples.

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~3.4x faster than the naive.
This commit is contained in:
Azusa Yamaguchi
2015-12-29 19:22:59 +00:00
parent f7d61b8b81
commit 98de1cbb6a
3 changed files with 116 additions and 12 deletions
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36
lib/qcd/action/gauge/PlaqPlusRectangleAction.h
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@@ -34,29 +34,43 @@ namespace Grid{
return action;
};
virtual void deriv(const GaugeField &U,GaugeField & dSdU) {
virtual void deriv(const GaugeField &Umu,GaugeField & dSdU) {
//extend Ta to include Lorentz indexes
RealD factor_p = c_plaq/RealD(Nc)*0.5;
RealD factor_r = c_rect/RealD(Nc)*0.5;
GaugeLinkField Umu(U._grid);
GaugeLinkField dSdU_mu(U._grid);
GaugeLinkField staple(U._grid);
GridBase *grid = Umu._grid;
std::vector<GaugeLinkField> U (Nd,grid);
std::vector<GaugeLinkField> U2(Nd,grid);
for(int mu=0;mu<Nd;mu++){
U[mu] = PeekIndex<LorentzIndex>(Umu,mu);
WilsonLoops<GaugeField>::RectStapleDouble(U2[mu],U[mu],mu);
}
GaugeLinkField dSdU_mu(grid);
GaugeLinkField staple(grid);
for (int mu=0; mu < Nd; mu++){
Umu = PeekIndex<LorentzIndex>(U,mu);
// Staple in direction mu
WilsonLoops<GaugeField>::Staple(staple,U,mu);
dSdU_mu = Ta(Umu*staple)*factor_p;
WilsonLoops<GaugeField>::RectStaple(staple,U,mu);
dSdU_mu = dSdU_mu + Ta(Umu*staple)*factor_r;
WilsonLoops<GaugeField>::Staple(staple,Umu,mu);
dSdU_mu = Ta(U[mu]*staple)*factor_p;
// WilsonLoops<GaugeField>::RectStaple(staple,Umu,mu);
WilsonLoops<GaugeField>::RectStapleOptimised(staple,U2,U,mu);
dSdU_mu = dSdU_mu + Ta(U[mu]*staple)*factor_r;
PokeIndex<LorentzIndex>(dSdU, dSdU_mu, mu);
}
};
};
// Convenience for common physically defined cases.

2
lib/qcd/utils/CovariantCshift.h
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@@ -5,6 +5,7 @@ namespace QCD {
////////////////////////////////////////////////////////////////////////
// Low performance implementation of CovariantCshift API
////////////////////////////////////////////////////////////////////////
// Make these members of an Impl class for BC's.
template<class covariant,class gauge> Lattice<covariant> CovShiftForward(const Lattice<gauge> &Link,
int mu,
const Lattice<covariant> &field)
@@ -19,5 +20,6 @@ template<class covariant,class gauge> Lattice<covariant> CovShiftBackward(const
tmp = adj(Link)*field;
return Cshift(tmp,mu,-1);// moves towards positive mu
}
}}
#endif

88
lib/qcd/utils/WilsonLoops.h
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@@ -206,8 +206,96 @@ public:
//////////////////////////////////////////////////
// the sum over all staples on each site
//////////////////////////////////////////////////
static void RectStapleDouble(GaugeMat &U2,const GaugeMat & U,int mu){
U2 = U * Cshift(U,mu,1);
}
static void RectStapleOptimised(GaugeMat &Stap,std::vector<GaugeMat> &U2,std::vector<GaugeMat> &U,int mu){
Stap = zero;
GridBase *grid = U[0]._grid;
GaugeMat Staple2x1 (grid);
GaugeMat tmp (grid);
for(int nu=0;nu<Nd;nu++){
if ( nu!=mu) {
// Up staple ___ ___
// | |
tmp = Cshift(adj(U[nu]),nu,-1);
tmp = adj(U2[mu])*tmp;
tmp = Cshift(tmp,mu,-2);
Staple2x1 = CovShiftForward (U[nu],nu,tmp);
// Down staple
// |___ ___|
//
tmp = adj(U2[mu])*U[nu];
Staple2x1+= CovShiftBackward(U[nu],nu,Cshift(tmp,mu,-2));
// ___ ___
// | ___|
// |___ ___|
//
Stap+= Cshift(CovShiftForward (U[mu],mu,Staple2x1),mu,1);
// ___ ___
// |___ |
// |___ ___|
//
// tmp= Staple2x1* Cshift(U[mu],mu,-2);
// Stap+= Cshift(tmp,mu,1) ;
Stap+= Cshift(Staple2x1,mu,1)*Cshift(U[mu],mu,-1); ;
// --
// | |
//
// | |
tmp = Cshift(adj(U2[nu]),nu,-2);
tmp = CovShiftBackward(U[mu],mu,tmp);
tmp = U2[nu]*Cshift(tmp,nu,2);
Stap+= Cshift(tmp, mu, 1);
// | |
//
// | |
// --
tmp = CovShiftBackward(U[mu],mu,U2[nu]);
tmp = adj(U2[nu])*tmp;
tmp = Cshift(tmp,nu,-2);
Stap+=Cshift(tmp, mu, 1);
}}
}
static void RectStaple(GaugeMat &Stap,const GaugeLorentz &Umu,int mu){
#if 1
RectStapleUnoptimised(Stap,Umu,mu);
#else
GridBase *grid = Umu._grid;
std::vector<GaugeMat> U (Nd,grid);
std::vector<GaugeMat> U2(Nd,grid);
for(int mu=0;mu<Nd;mu++){
U[mu] = PeekIndex<LorentzIndex>(Umu,mu);
RectStapleDouble(U2[mu],U[mu],mu);
}
RectStapleOptimised(Stap,U2,U,mu);
#endif
}
static void RectStapleUnoptimised(GaugeMat &Stap,const GaugeLorentz &Umu,int mu){
GridBase *grid = Umu._grid;
std::vector<GaugeMat> U(4,grid);