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Grid/lib/qcd/utils/WilsonLoops.h
Peter Boyle dc814f30da Binary IO file for generic Grid array parallel I/O.
Number of IO MPI tasks can be varied by selecting which
dimensions use parallel IO and which dimensions use Serial send to boss
I/O.

Thus can neck down from, say 1024 nodes = 4x4x8x8 to {1,8,32,64,128,256,1024} nodes
doing the I/O.

Interpolates nicely between ALL nodes write their data, a single boss per time-plane
in processor space [old UKQCD fortran code did this], and a single node doing all I/O.

Not sure I have the transfer sizes big enough and am not overly convinced fstream
is guaranteed to not give buffer inconsistencies unless I set streambuf size to zero.

Practically it has worked on 8 tasks, 2x1x2x2 writing /cloning NERSC configurations
on my MacOS + OpenMPI and Clang environment.

It is VERY easy to switch to pwrite at a later date, and also easy to send x-strips around from
each node in order to gather bigger chunks at the syscall level.

That would push us up to the circa 8x 18*4*8 == 4KB size write chunk, and by taking, say, x/y non
parallel we get to 16MB contiguous chunks written in multi 4KB transactions
per IOnode in 64^3 lattices for configuration I/O.

I suspect this is fine for system performance.
2015-08-26 13:40:29 +01:00

152 lines
4.5 KiB
C++

#ifndef QCD_UTILS_WILSON_LOOPS_H
#define QCD_UTILS_WILSON_LOOPS_H
namespace Grid {
namespace QCD {
// Common wilson loop observables
template<class GaugeMat,class GaugeLorentz>
class WilsonLoops {
public:
//////////////////////////////////////////////////
// directed plaquette oriented in mu,nu plane
//////////////////////////////////////////////////
static void dirPlaquette(GaugeMat &plaq,const std::vector<GaugeMat> &U, const int mu, const int nu)
{
plaq=CovShiftForward(U[mu],mu,U[nu])*adj(CovShiftForward(U[nu],nu,U[mu]));
}
//////////////////////////////////////////////////
// trace of directed plaquette oriented in mu,nu plane
//////////////////////////////////////////////////
static void traceDirPlaquette(LatticeComplex &plaq, const std::vector<GaugeMat> &U, const int mu, const int nu)
{
GaugeMat sp(U[0]._grid);
dirPlaquette(sp,U,mu,nu);
plaq=trace(sp);
}
//////////////////////////////////////////////////
// sum over all planes of plaquette
//////////////////////////////////////////////////
static void sitePlaquette(LatticeComplex &Plaq,const std::vector<GaugeMat> &U)
{
LatticeComplex sitePlaq(U[0]._grid);
Plaq=zero;
for(int mu=1;mu<Nd;mu++){
for(int nu=0;nu<mu;nu++){
traceDirPlaquette(sitePlaq,U,mu,nu);
Plaq = Plaq + sitePlaq;
}
}
}
//////////////////////////////////////////////////
// sum over all x,y,z,t and over all planes of plaquette
//////////////////////////////////////////////////
static RealD sumPlaquette(const GaugeLorentz &Umu){
std::vector<GaugeMat> U(4,Umu._grid);
for(int mu=0;mu<Nd;mu++){
U[mu] = PeekIndex<LorentzIndex>(Umu,mu);
}
LatticeComplex Plaq(Umu._grid);
sitePlaquette(Plaq,U);
TComplex Tp = sum(Plaq);
Complex p = TensorRemove(Tp);
return p.real();
}
//////////////////////////////////////////////////
// average over all x,y,z,t and over all planes of plaquette
//////////////////////////////////////////////////
static RealD avgPlaquette(const GaugeLorentz &Umu){
RealD sumplaq = sumPlaquette(Umu);
double vol = Umu._grid->gSites();
double faces = (1.0*Nd*(Nd-1))/2.0;
return sumplaq/vol/faces/Nc; // Nd , Nc dependent... FIXME
}
static RealD linkTrace(const GaugeLorentz &Umu){
std::vector<GaugeMat> U(4,Umu._grid);
LatticeComplex Tr(Umu._grid); Tr=zero;
for(int mu=0;mu<Nd;mu++){
U[mu] = PeekIndex<LorentzIndex>(Umu,mu);
Tr = Tr+trace(U[mu]);
}
TComplex Tp = sum(Tr);
Complex p = TensorRemove(Tp);
double vol = Umu._grid->gSites();
return p.real()/vol/4.0/3.0;
};
//////////////////////////////////////////////////
// the sum over all staples on each site
//////////////////////////////////////////////////
static void Staple(GaugeMat &staple,const GaugeLorentz &Umu,int mu){
GridBase *grid = Umu._grid;
std::vector<GaugeMat> U(4,grid);
for(int d=0;d<Nd;d++){
U[d] = PeekIndex<LorentzIndex>(Umu,d);
}
staple = zero;
GaugeMat tmp(grid);
for(int nu=0;nu<Nd;nu++){
if(nu != mu) {
// mu
// ^
// |__ nu
// __ __
// | |
// __| = __| *
//
staple += CovShiftForward(U[nu],nu,U[mu])*Cshift(adj(U[nu]),mu,+1);
//
// __ __
// | |
// |__ = | * __
//
//
tmp = CovShiftForward (U[mu],mu,U[nu]);
staple+= CovShiftBackward(U[nu],nu,tmp);
}
}
}
//////////////////////////////////////////////////////
// Similar to above for rectangle is required
//////////////////////////////////////////////////////
/*
void siteRectangle(GaugeMat &plaq,const std::vector<GaugeMat> &U, const int mu, const int nu){
RealD avgRectangle(const std::vector<GaugeMat> &U){}
RealD avgRectangle(const std::vector<GaugeMat> &U, const int mu, const int nu){}
void traceRectangle(LatticeComplex &plaq,const std::vector<GaugeMat> &U, const int mu, const int nu){}
void siteRectangle(GaugeMat &plaq,const std::vector<GaugeMat> &U, const int mu, const int nu){}
*/
};
typedef WilsonLoops<LatticeColourMatrix,LatticeGaugeField> ColourWilsonLoops;
typedef WilsonLoops<LatticeColourMatrix,LatticeGaugeField> U1WilsonLoops;
typedef WilsonLoops<LatticeColourMatrix,LatticeGaugeField> SU2WilsonLoops;
typedef WilsonLoops<LatticeColourMatrix,LatticeGaugeField> SU3WilsonLoops;
}}
#endif