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Added topological charge measurement

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This commit is contained in:
Guido Cossu
2017-03-17 16:14:57 +09:00
parent 91886068fe
commit 3d0fe15374
7 changed files with 87 additions and 18 deletions
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47
lib/qcd/observables/topological_charge.h
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@ -31,19 +31,54 @@ directory
#define HMC_TOP_CHARGE_H
namespace Grid {
namespace QCD (
namespace QCD {
// this is only defined for a gauge theory
template <class Impl>
class TopologicalCharge : public HmcObservable<typename Impl::Field> {
private:
std::string Stem;
public:
// here forces the Impl to be of gauge fields
// if not the compiler will complain
INHERIT_GIMPL_TYPES(Impl);
// necessary for HmcObservable compatibility
typedef typename Impl::Field Field;
void TrajectoryComplete(int traj,
Field &U,
GridSerialRNG &sRNG,
GridParallelRNG &pRNG) {
// 4d topological charge
// Bx = -iF(y,z), By = -iF(z,y), Bz = -iF(x,y)
GaugeLinkField Bx(U._grid), By(U._grid), Bz(U._grid);
WilsonLoops<Impl>::FieldStrength(Bx, U, Ydir, Zdir);
WilsonLoops<Impl>::FieldStrength(By, U, Zdir, Xdir);
WilsonLoops<Impl>::FieldStrength(Bz, U, Xdir, Ydir);
// Ex = -iF(t,x), Ey = -iF(t,y), Ez = -iF(t,z)
GaugeLinkField Ex(U._grid), Ey(U._grid), Ez(U._grid);
WilsonLoops<Impl>::FieldStrength(Ex, U, Tdir, Xdir);
WilsonLoops<Impl>::FieldStrength(Ey, U, Tdir, Ydir);
WilsonLoops<Impl>::FieldStrength(Ez, U, Tdir, Zdir);
double coeff = 8.0/(32.0*M_PI*M_PI);
LatticeComplex qfield = coeff*trace(Bx*Ex + By*Ey + Bz*Ez);
TComplex Tq = sum(qfield);
Real q = TensorRemove(Tq).real();
int def_prec = std::cout.precision();
std::cout << GridLogMessage
<< std::setprecision(std::numeric_limits<Real>::digits10 + 1)
<< "Topological Charge: [ " << traj << " ] "<< q << std::endl;
std::cout.precision(def_prec);
}
};
)
}
}
#endif // HMC_TOP_CHARGE_H