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Grid/tests/forces/Test_gp_rect_force.cc
paboyle c399c2b44d Guido broke the charge conjugate plaquette action with premature optimisation.
This sector of the code does not matter for anything other than Guido's quenched HMC
studies, and any plaq specific optimisations should be retained in a private branch
instead of destroying the code simplicity.
2018-03-05 12:55:41 +00:00

126 lines
3.8 KiB
C++

/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./tests/Test_gp_rect_force.cc
Copyright (C) 2015
Author: paboyle <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 */
#include <Grid/Grid.h>
using namespace std;
using namespace Grid;
using namespace Grid::QCD;
int main (int argc, char ** argv)
{
Grid_init(&argc,&argv);
std::vector<int> latt_size = GridDefaultLatt();
std::vector<int> simd_layout = GridDefaultSimd(Nd,vComplex::Nsimd());
std::vector<int> mpi_layout = GridDefaultMpi();
GridCartesian Grid(latt_size,simd_layout,mpi_layout);
GridRedBlackCartesian RBGrid(&Grid);
int threads = GridThread::GetThreads();
std::cout<<GridLogMessage << "Grid is setup to use "<<threads<<" threads"<<std::endl;
std::vector<int> seeds({1,2,3,4});
GridParallelRNG pRNG(&Grid);
pRNG.SeedFixedIntegers(std::vector<int>({45,12,81,9}));
LatticeGaugeField U(&Grid);
SU3::HotConfiguration(pRNG,U);
double beta = 1.0;
double c1 = 0.331;
ConjugatePlaqPlusRectangleActionR Action(beta,c1);
// ConjugateWilsonGaugeActionR Action(beta);
//WilsonGaugeActionR Action(beta);
ComplexD S = Action.S(U);
// get the deriv of phidag MdagM phi with respect to "U"
LatticeGaugeField UdSdU(&Grid);
Action.deriv(U,UdSdU);
////////////////////////////////////
// Modify the gauge field a little
////////////////////////////////////
RealD dt = 0.0001;
LatticeColourMatrix mommu(&Grid);
LatticeColourMatrix forcemu(&Grid);
LatticeGaugeField mom(&Grid);
LatticeGaugeField Uprime(&Grid);
for(int mu=0;mu<Nd;mu++){
SU3::GaussianFundamentalLieAlgebraMatrix(pRNG, mommu); // Traceless antihermitian momentum; gaussian in lie alg
PokeIndex<LorentzIndex>(mom,mommu,mu);
// fourth order exponential approx
parallel_for(auto i=mom.begin();i<mom.end();i++){ // exp(pmu dt) * Umu
Uprime[i](mu) = U[i](mu) + mom[i](mu)*U[i](mu)*dt ;
}
}
ComplexD Sprime = Action.S(Uprime);
//////////////////////////////////////////////
// Use derivative to estimate dS
//////////////////////////////////////////////
LatticeComplex dS(&Grid); dS = zero;
for(int mu=0;mu<Nd;mu++){
auto UdSdUmu = PeekIndex<LorentzIndex>(UdSdU,mu);
mommu = PeekIndex<LorentzIndex>(mom,mu);
// Update gauge action density
// U = exp(p dt) U
// dU/dt = p U
// so dSdt = trace( dUdt dSdU) = trace( p UdSdUmu )
dS = dS - trace(mommu*UdSdUmu)*dt*2.0;
}
ComplexD dSpred = sum(dS);
std::cout << GridLogMessage << " S "<<S<<std::endl;
std::cout << GridLogMessage << " Sprime "<<Sprime<<std::endl;
std::cout << GridLogMessage << "dS "<<Sprime-S<<std::endl;
std::cout << GridLogMessage << "pred dS "<< dSpred <<std::endl;
assert( fabs(real(Sprime-S-dSpred)) < 1.0e-2 ) ;
std::cout<< GridLogMessage << "Done" <<std::endl;
Grid_finalize();
}