portelli/Grid
1
0
Fork 0
mirror of https://github.com/paboyle/Grid.git synced 2025-04-10 14:10:46 +01:00
Code Releases Activity
Grid/Grid/qcd/action/gauge/Photon.h

326 lines
9.2 KiB
C++
Raw Blame History

/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./lib/qcd/action/gauge/Photon.h
Copyright (C) 2015
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
See the full license in the file "LICENSE" in the top level distribution directory
*************************************************************************************/
/* END LEGAL */
#ifndef QCD_PHOTON_ACTION_H
#define QCD_PHOTON_ACTION_H
namespace Grid{
namespace QCD{
template <class S>
class QedGImpl
{
public:
typedef S Simd;
template <typename vtype>
using iImplGaugeLink = iScalar<iScalar<iScalar<vtype>>>;
template <typename vtype>
using iImplGaugeField = iVector<iScalar<iScalar<vtype>>, Nd>;
typedef iImplGaugeLink<Simd> SiteLink;
typedef iImplGaugeField<Simd> SiteField;
typedef SiteLink SiteComplex;
typedef Lattice<SiteLink> LinkField;
typedef Lattice<SiteField> Field;
typedef Field ComplexField;
};
typedef QedGImpl<vComplex> QedGImplR;
template <class GImpl>
class Photon
{
public:
INHERIT_GIMPL_TYPES(GImpl);
typedef typename SiteGaugeLink::scalar_object ScalarSite;
typedef typename ScalarSite::scalar_type ScalarComplex;
GRID_SERIALIZABLE_ENUM(Gauge, undef, feynman, 1, coulomb, 2, landau, 3);
GRID_SERIALIZABLE_ENUM(ZmScheme, undef, qedL, 1, qedTL, 2);
public:
Photon(GridBase *grid, Gauge gauge, ZmScheme zmScheme, std::vector<Real> improvement);
Photon(GridBase *grid, Gauge gauge, ZmScheme zmScheme);
virtual ~Photon(void) = default;
void FreePropagator(const GaugeField &in, GaugeField &out);
void MomentumSpacePropagator(const GaugeField &in, GaugeField &out);
void StochasticWeight(GaugeLinkField &weight);
void StochasticField(GaugeField &out, GridParallelRNG &rng);
void StochasticField(GaugeField &out, GridParallelRNG &rng,
const GaugeLinkField &weight);
void UnitField(GaugeField &out);
private:
void makeSpatialNorm(LatticeInteger &spNrm);
void makeKHat(std::vector<GaugeLinkField> &khat);
void makeInvKHatSquared(GaugeLinkField &out);
void zmSub(GaugeLinkField &out);
void transverseProjectSpatial(GaugeField &out);
void gaugeTransform(GaugeField &out);
private:
GridBase *grid_;
Gauge gauge_;
ZmScheme zmScheme_;
std::vector<Real> improvement_;
};
typedef Photon<QedGImplR> PhotonR;
template<class GImpl>
Photon<GImpl>::Photon(GridBase *grid, Gauge gauge, ZmScheme zmScheme,
std::vector<Real> improvements)
: grid_(grid), gauge_(gauge), zmScheme_(zmScheme), improvement_(improvements)
{}
template<class GImpl>
Photon<GImpl>::Photon(GridBase *grid, Gauge gauge, ZmScheme zmScheme)
: Photon(grid, gauge, zmScheme, std::vector<Real>())
{}
template<class GImpl>
void Photon<GImpl>::FreePropagator(const GaugeField &in, GaugeField &out)
{
FFT theFFT(dynamic_cast<GridCartesian *>(grid_));
GaugeField in_k(grid_);
GaugeField prop_k(grid_);
theFFT.FFT_all_dim(in_k, in, FFT::forward);
MomentumSpacePropagator(prop_k, in_k);
theFFT.FFT_all_dim(out, prop_k, FFT::backward);
}
template<class GImpl>
void Photon<GImpl>::makeSpatialNorm(LatticeInteger &spNrm)
{
LatticeInteger coor(grid_);
std::vector<int> l = grid_->FullDimensions();
spNrm = zero;
for(int mu = 0; mu < grid_->Nd() - 1; mu++)
{
LatticeCoordinate(coor, mu);
coor = where(coor < Integer(l[mu]/2), coor, coor - Integer(l[mu]));
spNrm = spNrm + coor*coor;
}
}
template<class GImpl>
void Photon<GImpl>::makeKHat(std::vector<GaugeLinkField> &khat)
{
const unsigned int nd = grid_->Nd();
std::vector<int> l = grid_->FullDimensions();
Complex ci(0., 1.);
khat.resize(nd, grid_);
for (unsigned int mu = 0; mu < nd; ++mu)
{
Real twoPiL = M_PI*2./l[mu];
LatticeCoordinate(khat[mu], mu);
khat[mu] = exp(0.5*ci*khat[mu])*2.*sin(.5*twoPiL*khat[mu]);
}
}
template<class GImpl>
void Photon<GImpl>::makeInvKHatSquared(GaugeLinkField &out)
{
std::vector<GaugeLinkField> khat;
GaugeLinkField lone(grid_);
const unsigned int nd = grid_->Nd();
std::vector<int> zm(nd, 0);
ScalarSite one = ScalarComplex(1., 0.), z = ScalarComplex(0., 0.);
out = zero;
makeKHat(khat);
for(int mu = 0; mu < nd; mu++)
{
out = out + khat[mu]*conjugate(khat[mu]);
}
lone = ScalarComplex(1., 0.);
pokeSite(one, out, zm);
out = lone/out;
pokeSite(z, out, zm);
}
template<class GImpl>
void Photon<GImpl>::zmSub(GaugeLinkField &out)
{
switch (zmScheme_)
{
case ZmScheme::qedTL:
{
std::vector<int> zm(grid_->Nd(), 0);
ScalarSite z = ScalarComplex(0., 0.);
pokeSite(z, out, zm);
break;
}
case ZmScheme::qedL:
{
LatticeInteger spNrm(grid_);
makeSpatialNorm(spNrm);
out = where(spNrm == Integer(0), 0.*out, out);
for(int i = 0; i < improvement_.size(); i++)
{
Real f = sqrt(improvement_[i] + 1);
out = where(spNrm == Integer(i + 1), f*out, out);
}
}
default:
assert(0);
break;
}
}
template<class GImpl>
void Photon<GImpl>::transverseProjectSpatial(GaugeField &out)
{
const unsigned int nd = grid_->Nd();
GaugeLinkField invKHat(grid_), cst(grid_);
LatticeInteger spNrm(grid_);
std::vector<GaugeLinkField> khat, a(nd, grid_), aProj(nd, grid_);
invKHat = zero;
makeSpatialNorm(spNrm);
makeKHat(khat);
for (unsigned int mu = 0; mu < nd; ++mu)
{
a[mu] = peekLorentz(out, mu);
if (mu < nd - 1)
{
invKHat += khat[mu]*conjugate(khat[mu]);
}
}
cst = ScalarComplex(1., 0.);
invKHat = where(spNrm == Integer(0), cst, invKHat);
invKHat = cst/invKHat;
cst = zero;
invKHat = where(spNrm == Integer(0), cst, invKHat);
for (unsigned int mu = 0; mu < nd; ++mu)
{
aProj[mu] = a[mu];
for (unsigned int nu = 0; nu < nd - 1; ++nu)
{
aProj[mu] -= invKHat*khat[mu]*conjugate(khat[nu])*a[nu];
}
pokeLorentz(out, aProj[mu], mu);
}
}
template<class GImpl>
void Photon<GImpl>::gaugeTransform(GaugeField &out)
{
switch (gauge_)
{
case Gauge::feynman:
break;
case Gauge::coulomb:
transverseProjectSpatial(out);
break;
case Gauge::landau:
assert(0);
break;
default:
assert(0);
break;
}
}
template<class GImpl>
void Photon<GImpl>::MomentumSpacePropagator(const GaugeField &in,
GaugeField &out)
{
LatticeComplex momProp(grid_);
makeInvKHatSquared(momProp);
zmSub(momProp);
out = in*momProp;
}
template<class GImpl>
void Photon<GImpl>::StochasticWeight(GaugeLinkField &weight)
{
const unsigned int nd = grid_->Nd();
std::vector<int> l = grid_->FullDimensions();
Integer vol = 1;
for(unsigned int mu = 0; mu < nd; mu++)
{
vol = vol*l[mu];
}
makeInvKHatSquared(weight);
weight = sqrt(vol)*sqrt(weight);
zmSub(weight);
}
template<class GImpl>
void Photon<GImpl>::StochasticField(GaugeField &out, GridParallelRNG &rng)
{
GaugeLinkField weight(grid_);
StochasticWeight(weight);
StochasticField(out, rng, weight);
}
template<class GImpl>
void Photon<GImpl>::StochasticField(GaugeField &out, GridParallelRNG &rng,
const GaugeLinkField &weight)
{
const unsigned int nd = grid_->Nd();
GaugeLinkField r(grid_);
GaugeField aTilde(grid_);
FFT fft(dynamic_cast<GridCartesian *>(grid_));
for(unsigned int mu = 0; mu < nd; mu++)
{
gaussian(rng, r);
r = weight*r;
pokeLorentz(aTilde, r, mu);
}
gaugeTransform(aTilde);
fft.FFT_all_dim(out, aTilde, FFT::backward);
out = real(out);
}
template<class GImpl>
void Photon<GImpl>::UnitField(GaugeField &out)
{
const unsigned int nd = grid_->Nd();
GaugeLinkField r(grid_);
r = ScalarComplex(1., 0.);
for(unsigned int mu = 0; mu < nd; mu++)
{
pokeLorentz(out, r, mu);
}
out = real(out);
}
}}
#endif
View Git Blame Copy Permalink