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PauliVillars based 4D -> 5D reconstruction with Fourier Accelerated PV inverse

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by Christoph. Differs from the one by Rudy in BFM since it vectorises the twisted
4D solves in pairs.
This commit is contained in:
Peter Boyle
2018-10-11 12:35:32 +01:00
parent fe6a372f75
commit 49f25e08e8
9 changed files with 823 additions and 10 deletions
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237
Grid/qcd/action/fermion/FourierAcceleratedPV.h Normal file
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/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./lib/qcd/action/fermion/FourierAcceleratedPV.h
Copyright (C) 2015
Author: Christoph Lehner
Author: Peter Boyle <pabobyle@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 */
#pragma once
namespace Grid {
namespace QCD {
template<typename M>
void get_real_const_bc(M& m, RealD& _b, RealD& _c) {
ComplexD b,c;
b=m.bs[0];
c=m.cs[0];
std::cout << GridLogMessage << "b=" << b << ", c=" << c << std::endl;
for (size_t i=1;i<m.bs.size();i++) {
assert(m.bs[i] == b);
assert(m.cs[i] == c);
}
assert(b.imag() == 0.0);
assert(c.imag() == 0.0);
_b = b.real();
_c = c.real();
}
template<typename Vi, typename M, typename G>
class FourierAcceleratedPV {
public:
ConjugateGradient<Vi> &cg;
M& dwfPV;
G& Umu;
GridCartesian* grid5D;
GridRedBlackCartesian* gridRB5D;
int group_in_s;
FourierAcceleratedPV(M& _dwfPV, G& _Umu, ConjugateGradient<Vi> &_cg, int _group_in_s = 2)
: dwfPV(_dwfPV), Umu(_Umu), cg(_cg), group_in_s(_group_in_s)
{
assert( dwfPV.FermionGrid()->_fdimensions[0] % (2*group_in_s) == 0);
grid5D = QCD::SpaceTimeGrid::makeFiveDimGrid(2*group_in_s, (GridCartesian*)Umu._grid);
gridRB5D = QCD::SpaceTimeGrid::makeFiveDimRedBlackGrid(2*group_in_s, (GridCartesian*)Umu._grid);
}
void rotatePV(const Vi& _src, Vi& dst, bool forward) const {
GridStopWatch gsw1, gsw2;
typedef typename Vi::scalar_type Coeff_t;
int Ls = dst._grid->_fdimensions[0];
Vi _tmp(dst._grid);
double phase = M_PI / (double)Ls;
Coeff_t bzero(0.0,0.0);
FFT theFFT((GridCartesian*)dst._grid);
if (!forward) {
gsw1.Start();
for (int s=0;s<Ls;s++) {
Coeff_t a(::cos(phase*s),-::sin(phase*s));
axpby_ssp(_tmp,a,_src,bzero,_src,s,s);
}
gsw1.Stop();
gsw2.Start();
theFFT.FFT_dim(dst,_tmp,0,FFT::forward);
gsw2.Stop();
} else {
gsw2.Start();
theFFT.FFT_dim(_tmp,_src,0,FFT::backward);
gsw2.Stop();
gsw1.Start();
for (int s=0;s<Ls;s++) {
Coeff_t a(::cos(phase*s),::sin(phase*s));
axpby_ssp(dst,a,_tmp,bzero,_tmp,s,s);
}
gsw1.Stop();
}
std::cout << GridLogMessage << "Timing rotatePV: " << gsw1.Elapsed() << ", " << gsw2.Elapsed() << std::endl;
}
void pvInv(const Vi& _src, Vi& _dst) const {
std::cout << GridLogMessage << "Fourier-Accelerated Outer Pauli Villars"<<std::endl;
typedef typename Vi::scalar_type Coeff_t;
int Ls = _dst._grid->_fdimensions[0];
GridStopWatch gswT;
gswT.Start();
RealD b,c;
get_real_const_bc(dwfPV,b,c);
RealD M5 = dwfPV.M5;
// U(true) Rightinv TMinv U(false) = Minv
Vi _src_diag(_dst._grid);
Vi _src_diag_slice(dwfPV.GaugeGrid());
Vi _dst_diag_slice(dwfPV.GaugeGrid());
Vi _src_diag_slices(grid5D);
Vi _dst_diag_slices(grid5D);
Vi _dst_diag(_dst._grid);
rotatePV(_src,_src_diag,false);
// now do TM solves
Gamma G5(Gamma::Algebra::Gamma5);
GridStopWatch gswA, gswB;
gswA.Start();
typedef typename M::Impl_t Impl;
//WilsonTMFermion<Impl> tm(x.Umu,*x.UGridF,*x.UrbGridF,0.0,0.0,solver_outer.parent.par.wparams_f);
std::vector<RealD> vmass(grid5D->_fdimensions[0],0.0);
std::vector<RealD> vmu(grid5D->_fdimensions[0],0.0);
WilsonTMFermion5D<Impl> tm(Umu,*grid5D,*gridRB5D,
*(GridCartesian*)dwfPV.GaugeGrid(),
*(GridRedBlackCartesian*)dwfPV.GaugeRedBlackGrid(),
vmass,vmu);
//SchurRedBlackDiagTwoSolve<Vi> sol(cg);
SchurRedBlackDiagMooeeSolve<Vi> sol(cg); // same performance as DiagTwo
gswA.Stop();
gswB.Start();
for (int sgroup=0;sgroup<Ls/2/group_in_s;sgroup++) {
for (int sidx=0;sidx<group_in_s;sidx++) {
int s = sgroup*group_in_s + sidx;
int sprime = Ls-s-1;
RealD phase = M_PI / (RealD)Ls * (2.0 * s + 1.0);
RealD cosp = ::cos(phase);
RealD sinp = ::sin(phase);
RealD denom = b*b + c*c + 2.0*b*c*cosp;
RealD mass = -(b*b*M5 + c*(1.0 - cosp + c*M5) + b*(-1.0 + cosp + 2.0*c*cosp*M5))/denom;
RealD mu = (b+c)*sinp/denom;
vmass[2*sidx + 0] = mass;
vmass[2*sidx + 1] = mass;
vmu[2*sidx + 0] = mu;
vmu[2*sidx + 1] = -mu;
}
tm.update(vmass,vmu);
for (int sidx=0;sidx<group_in_s;sidx++) {
int s = sgroup*group_in_s + sidx;
int sprime = Ls-s-1;
ExtractSlice(_src_diag_slice,_src_diag,s,0);
InsertSlice(_src_diag_slice,_src_diag_slices,2*sidx + 0,0);
ExtractSlice(_src_diag_slice,_src_diag,sprime,0);
InsertSlice(_src_diag_slice,_src_diag_slices,2*sidx + 1,0);
}
GridStopWatch gsw;
gsw.Start();
_dst_diag_slices = zero; // zero guess
sol(tm,_src_diag_slices,_dst_diag_slices);
gsw.Stop();
std::cout << GridLogMessage << "Solve[sgroup=" << sgroup << "] completed in " << gsw.Elapsed() << ", " << gswA.Elapsed() << std::endl;
for (int sidx=0;sidx<group_in_s;sidx++) {
int s = sgroup*group_in_s + sidx;
int sprime = Ls-s-1;
RealD phase = M_PI / (RealD)Ls * (2.0 * s + 1.0);
RealD cosp = ::cos(phase);
RealD sinp = ::sin(phase);
// now rotate with inverse of
Coeff_t pA = b + c*cosp;
Coeff_t pB = - Coeff_t(0.0,1.0)*c*sinp;
Coeff_t pABden = pA*pA - pB*pB;
// (pA + pB * G5) * (pA - pB*G5) = (pA^2 - pB^2)
ExtractSlice(_dst_diag_slice,_dst_diag_slices,2*sidx + 0,0);
_dst_diag_slice = (pA/pABden) * _dst_diag_slice - (pB/pABden) * (G5 * _dst_diag_slice);
InsertSlice(_dst_diag_slice,_dst_diag,s,0);
ExtractSlice(_dst_diag_slice,_dst_diag_slices,2*sidx + 1,0);
_dst_diag_slice = (pA/pABden) * _dst_diag_slice + (pB/pABden) * (G5 * _dst_diag_slice);
InsertSlice(_dst_diag_slice,_dst_diag,sprime,0);
}
}
gswB.Stop();
rotatePV(_dst_diag,_dst,true);
gswT.Stop();
std::cout << GridLogMessage << "PV completed in " << gswT.Elapsed() << " (Setup: " << gswA.Elapsed() << ", s-loop: " << gswB.Elapsed() << ")" << std::endl;
}
};
}}