/*************************************************************************************

Grid physics library, www.github.com/paboyle/Grid

Source file: ./lib/qcd/action/fermion/WilsonFermion.cc

Copyright (C) 2022

Author: Peter Boyle <pabobyle@ph.ed.ac.uk>
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
Author: Peter Boyle <peterboyle@Peters-MacBook-Pro-2.local>
Author: paboyle <paboyle@ph.ed.ac.uk>
Author: Fabian Joswig <fabian.joswig@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/qcd/action/fermion/FermionCore.h>
#include <Grid/qcd/action/fermion/WilsonFermion.h>

NAMESPACE_BEGIN(Grid);

/////////////////////////////////
// Constructor and gauge import
/////////////////////////////////

//template <class Impl>
//WilsonFermion<Impl>::WilsonFermion(GaugeField &_Umu, GridCartesian &Fgrid,
//                                   GridRedBlackCartesian &Hgrid, RealD _mass,
//                                   const ImplParams &p,
//                                   const WilsonAnisotropyCoefficients &anis)
//  :
//    Kernels(p),
//    _grid(&Fgrid),
//    _cbgrid(&Hgrid),
//    Stencil(&Fgrid, npoint, Even, directions, displacements,p),
//    StencilEven(&Hgrid, npoint, Even, directions,displacements,p),  // source is Even
//    StencilOdd(&Hgrid, npoint, Odd, directions,displacements,p),  // source is Odd
//    mass(_mass),
//    Lebesgue(_grid),
//    LebesgueEvenOdd(_cbgrid),
//    Umu(&Fgrid),
//    UmuEven(&Hgrid),
//    UmuOdd(&Hgrid),
//      _tmp(&Hgrid),
//      anisotropyCoeff(anis)
//{
//  Stencil.lo     = &Lebesgue;
//  StencilEven.lo = &LebesgueEvenOdd;
//  StencilOdd.lo  = &LebesgueEvenOdd;
//  // Allocate the required comms buffer
//  ImportGauge(_Umu);
//  if  (anisotropyCoeff.isAnisotropic){
//    diag_mass = mass + 1.0 + (Nd-1)*(anisotropyCoeff.nu / anisotropyCoeff.xi_0);
//  } else {
//    diag_mass = 4.0 + mass;
//  }
//
//  int vol4;
//  vol4=Fgrid.oSites();
//  Stencil.BuildSurfaceList(1,vol4);
//  vol4=Hgrid.oSites();
//  StencilEven.BuildSurfaceList(1,vol4);
//  StencilOdd.BuildSurfaceList(1,vol4);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::ImportGauge(const GaugeField &_Umu)
//{
//  GaugeField HUmu(_Umu.Grid());
//
//  //Here multiply the anisotropy coefficients
//  if (anisotropyCoeff.isAnisotropic)
//  {
//
//    for (int mu = 0; mu < Nd; mu++)
//    {
//      GaugeLinkField U_dir = (-0.5)*PeekIndex<LorentzIndex>(_Umu, mu);
//      if (mu != anisotropyCoeff.t_direction)
//        U_dir *= (anisotropyCoeff.nu / anisotropyCoeff.xi_0);
//
//      PokeIndex<LorentzIndex>(HUmu, U_dir, mu);
//    }
//  }
//  else
//  {
//    HUmu = _Umu * (-0.5);
//  }
//  Impl::DoubleStore(GaugeGrid(), Umu, HUmu);
//  pickCheckerboard(Even, UmuEven, Umu);
//  pickCheckerboard(Odd, UmuOdd, Umu);
//}
//
///////////////////////////////
//// Implement the interface
///////////////////////////////
//
//template <class Impl>
//void WilsonFermion<Impl>::M(const FermionField &in, FermionField &out)
//{
//  out.Checkerboard() = in.Checkerboard();
//  Dhop(in, out, DaggerNo);
//  axpy(out, diag_mass, in, out);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::Mdag(const FermionField &in, FermionField &out)
//{
//  out.Checkerboard() = in.Checkerboard();
//  Dhop(in, out, DaggerYes);
//  axpy(out, diag_mass, in, out);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::Meooe(const FermionField &in, FermionField &out)
//{
//  if (in.Checkerboard() == Odd) {
//    DhopEO(in, out, DaggerNo);
//  } else {
//    DhopOE(in, out, DaggerNo);
//  }
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::MeooeDag(const FermionField &in, FermionField &out)
//{
//  if (in.Checkerboard() == Odd) {
//    DhopEO(in, out, DaggerYes);
//  } else {
//    DhopOE(in, out, DaggerYes);
//  }
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::Mooee(const FermionField &in, FermionField &out)
//{
//  out.Checkerboard() = in.Checkerboard();
//  typename FermionField::scalar_type scal(diag_mass);
//  out = scal * in;
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::MooeeDag(const FermionField &in, FermionField &out)
//{
//  out.Checkerboard() = in.Checkerboard();
//  Mooee(in, out);
//}
//
//template<class Impl>
//void WilsonFermion<Impl>::MooeeInv(const FermionField &in, FermionField &out)
//{
//  out.Checkerboard() = in.Checkerboard();
//  out = (1.0/(diag_mass))*in;
//}
//
//template<class Impl>
//void WilsonFermion<Impl>::MooeeInvDag(const FermionField &in, FermionField &out)
//{
//  out.Checkerboard() = in.Checkerboard();
//  MooeeInv(in,out);
//}
//template<class Impl>
//void WilsonFermion<Impl>::MomentumSpacePropagator(FermionField &out, const FermionField &in,RealD _m,std::vector<double> twist)
//{
//  typedef typename FermionField::vector_type vector_type;
//  typedef typename FermionField::scalar_type ScalComplex;
//  typedef Lattice<iSinglet<vector_type> > LatComplex;
//
//  // what type LatticeComplex
//  conformable(_grid,out.Grid());
//
//  Gamma::Algebra Gmu [] = {
//    Gamma::Algebra::GammaX,
//    Gamma::Algebra::GammaY,
//    Gamma::Algebra::GammaZ,
//    Gamma::Algebra::GammaT
//  };
//
//  Coordinate latt_size   = _grid->_fdimensions;
//
//  FermionField   num  (_grid); num  = Zero();
//  LatComplex    wilson(_grid); wilson= Zero();
//  LatComplex     one  (_grid); one = ScalComplex(1.0,0.0);
//
//  LatComplex denom(_grid); denom= Zero();
//  LatComplex kmu(_grid);
//  ScalComplex ci(0.0,1.0);
//  // momphase = n * 2pi / L
//  for(int mu=0;mu<Nd;mu++) {
//
//    LatticeCoordinate(kmu,mu);
//
//    RealD TwoPiL =  M_PI * 2.0/ latt_size[mu];
//
//    kmu = TwoPiL * kmu;
//    kmu = kmu + TwoPiL * one * twist[mu];//momentum for twisted boundary conditions
//
//    wilson = wilson + 2.0*sin(kmu*0.5)*sin(kmu*0.5); // Wilson term
//
//    num = num - sin(kmu)*ci*(Gamma(Gmu[mu])*in);    // derivative term
//
//    denom=denom + sin(kmu)*sin(kmu);
//  }
//
//  wilson = wilson + _m;     // 2 sin^2 k/2 + m
//
//  num   = num + wilson*in;     // -i gmu sin k + 2 sin^2 k/2 + m
//
//  denom= denom+wilson*wilson; // sin^2 k + (2 sin^2 k/2 + m)^2
//
//  denom= one/denom;
//
//  out = num*denom; // [ -i gmu sin k + 2 sin^2 k/2 + m] / [ sin^2 k + (2 sin^2 k/2 + m)^2 ]
//
//}
//
//
/////////////////////////////////////
//// Internal
/////////////////////////////////////
//
//template <class Impl>
//void WilsonFermion<Impl>::DerivInternal(StencilImpl &st, DoubledGaugeField &U,
//                                        GaugeField &mat, const FermionField &A,
//                                        const FermionField &B, int dag) {
//  assert((dag == DaggerNo) || (dag == DaggerYes));
//
//  Compressor compressor(dag);
//
//  FermionField Btilde(B.Grid());
//  FermionField Atilde(B.Grid());
//  Atilde = A;
//
//  st.HaloExchange(B, compressor);
//
//  for (int mu = 0; mu < Nd; mu++) {
//    ////////////////////////////////////////////////////////////////////////
//    // Flip gamma (1+g)<->(1-g) if dag
//    ////////////////////////////////////////////////////////////////////////
//    int gamma = mu;
//    if (!dag) gamma += Nd;
//
//    int Ls=1;
//    Kernels::DhopDirKernel(st, U, st.CommBuf(), Ls, B.Grid()->oSites(), B, Btilde, mu, gamma);
//
//    //////////////////////////////////////////////////
//    // spin trace outer product
//    //////////////////////////////////////////////////
//    Impl::InsertForce4D(mat, Btilde, Atilde, mu);
//  }
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::DhopDeriv(GaugeField &mat, const FermionField &U, const FermionField &V, int dag)
//{
//  conformable(U.Grid(), _grid);
//  conformable(U.Grid(), V.Grid());
//  conformable(U.Grid(), mat.Grid());
//
//  mat.Checkerboard() = U.Checkerboard();
//
//  DerivInternal(Stencil, Umu, mat, U, V, dag);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::DhopDerivOE(GaugeField &mat, const FermionField &U, const FermionField &V, int dag)
//{
//  conformable(U.Grid(), _cbgrid);
//  conformable(U.Grid(), V.Grid());
//  //conformable(U.Grid(), mat.Grid()); not general, leaving as a comment (Guido)
//  // Motivation: look at the SchurDiff operator
//
//  assert(V.Checkerboard() == Even);
//  assert(U.Checkerboard() == Odd);
//  mat.Checkerboard() = Odd;
//
//  DerivInternal(StencilEven, UmuOdd, mat, U, V, dag);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::DhopDerivEO(GaugeField &mat, const FermionField &U, const FermionField &V, int dag)
//{
//  conformable(U.Grid(), _cbgrid);
//  conformable(U.Grid(), V.Grid());
//  //conformable(U.Grid(), mat.Grid());
//
//  assert(V.Checkerboard() == Odd);
//  assert(U.Checkerboard() == Even);
//  mat.Checkerboard() = Even;
//
//  DerivInternal(StencilOdd, UmuEven, mat, U, V, dag);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::Dhop(const FermionField &in, FermionField &out, int dag)
//{
//  conformable(in.Grid(), _grid);  // verifies full grid
//  conformable(in.Grid(), out.Grid());
//
//  out.Checkerboard() = in.Checkerboard();
//
//  DhopInternal(Stencil, Lebesgue, Umu, in, out, dag);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::DhopOE(const FermionField &in, FermionField &out, int dag)
//{
//  conformable(in.Grid(), _cbgrid);    // verifies half grid
//  conformable(in.Grid(), out.Grid());  // drops the cb check
//
//  assert(in.Checkerboard() == Even);
//  out.Checkerboard() = Odd;
//
//  DhopInternal(StencilEven, LebesgueEvenOdd, UmuOdd, in, out, dag);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::DhopEO(const FermionField &in, FermionField &out,int dag)
//{
//  conformable(in.Grid(), _cbgrid);    // verifies half grid
//  conformable(in.Grid(), out.Grid());  // drops the cb check
//
//  assert(in.Checkerboard() == Odd);
//  out.Checkerboard() = Even;
//
//  DhopInternal(StencilOdd, LebesgueEvenOdd, UmuEven, in, out, dag);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::Mdir(const FermionField &in, FermionField &out, int dir, int disp)
//{
//  DhopDir(in, out, dir, disp);
//}
//template <class Impl>
//void WilsonFermion<Impl>::MdirAll(const FermionField &in, std::vector<FermionField> &out)
//{
//  DhopDirAll(in, out);
//}
////
//template <class Impl>
//void WilsonFermion<Impl>::DhopDir(const FermionField &in, FermionField &out, int dir, int disp)
//{
//  Compressor compressor(DaggerNo);
//  Stencil.HaloExchange(in, compressor);
//
//  int skip = (disp == 1) ? 0 : 1;
//  int dirdisp = dir + skip * 4;
//  int gamma = dir + (1 - skip) * 4;
//
//  DhopDirCalc(in, out, dirdisp, gamma, DaggerNo);
//};
//template <class Impl>
//void WilsonFermion<Impl>::DhopDirAll(const FermionField &in, std::vector<FermionField> &out)
//{
//  Compressor compressor(DaggerNo);
//  Stencil.HaloExchange(in, compressor);
//
//  assert((out.size()==8)||(out.size()==9));
//  for(int dir=0;dir<Nd;dir++){
//    for(int disp=-1;disp<=1;disp+=2){
//
//      int skip = (disp == 1) ? 0 : 1;
//      int dirdisp = dir + skip * 4;
//      int gamma = dir + (1 - skip) * 4;
//
//      DhopDirCalc(in, out[dirdisp], dirdisp, gamma, DaggerNo);
//    }
//  }
//}
//template <class Impl>
//void WilsonFermion<Impl>::DhopDirCalc(const FermionField &in, FermionField &out,int dirdisp, int gamma, int dag)
//{
//  int Ls=1;
//  uint64_t Nsite=in.oSites();
//  Kernels::DhopDirKernel(Stencil, Umu, Stencil.CommBuf(), Ls, Nsite, in, out, dirdisp, gamma);
//};
//
//template <class Impl>
//void WilsonFermion<Impl>::DhopInternal(StencilImpl &st, LebesgueOrder &lo,
//                                       DoubledGaugeField &U,
//                                       const FermionField &in,
//                                       FermionField &out, int dag)
//{
//#ifdef GRID_OMP
//  if ( WilsonKernelsStatic::Comms == WilsonKernelsStatic::CommsAndCompute )
//    DhopInternalOverlappedComms(st,lo,U,in,out,dag);
//  else
//#endif
//    DhopInternalSerial(st,lo,U,in,out,dag);
//}
//
//template <class Impl>
//void WilsonFermion<Impl>::DhopInternalOverlappedComms(StencilImpl &st, LebesgueOrder &lo,
//						      DoubledGaugeField &U,
//						      const FermionField &in,
//						      FermionField &out, int dag)
//{
//  GRID_TRACE("DhopOverlapped");
//  assert((dag == DaggerNo) || (dag == DaggerYes));
//
//  Compressor compressor(dag);
//  int len =  U.Grid()->oSites();
//
//  /////////////////////////////
//  // Start comms  // Gather intranode and extra node differentiated??
//  /////////////////////////////
//  std::vector<std::vector<CommsRequest_t> > requests;
//  st.Prepare();
//  {
//    GRID_TRACE("Gather");
//    st.HaloGather(in,compressor);
//  }
//
//  tracePush("Communication");
//  st.CommunicateBegin(requests);
//
//  /////////////////////////////
//  // Overlap with comms
//  /////////////////////////////
//  {
//    GRID_TRACE("MergeSHM");
//    st.CommsMergeSHM(compressor);
//  }
//
//  /////////////////////////////
//  // do the compute interior
//  /////////////////////////////
//  int Opt = WilsonKernelsStatic::Opt;
//  if (dag == DaggerYes) {
//    GRID_TRACE("DhopDagInterior");
//    Kernels::DhopDagKernel(Opt,st,U,st.CommBuf(),1,U.oSites(),in,out,1,0);
//  } else {
//    GRID_TRACE("DhopInterior");
//    Kernels::DhopKernel(Opt,st,U,st.CommBuf(),1,U.oSites(),in,out,1,0);
//  }
//
//  /////////////////////////////
//  // Complete comms
//  /////////////////////////////
//  st.CommunicateComplete(requests);
//  tracePop("Communication");
//
//  {
//    GRID_TRACE("Merge");
//    st.CommsMerge(compressor);
//  }
//  /////////////////////////////
//  // do the compute exterior
//  /////////////////////////////
//
//  if (dag == DaggerYes) {
//    GRID_TRACE("DhopDagExterior");
//    Kernels::DhopDagKernel(Opt,st,U,st.CommBuf(),1,U.oSites(),in,out,0,1);
//  } else {
//    GRID_TRACE("DhopExterior");
//    Kernels::DhopKernel(Opt,st,U,st.CommBuf(),1,U.oSites(),in,out,0,1);
//  }
//};
////
//template <class Impl>
//void WilsonFermion<Impl>::DhopInternalSerial(StencilImpl &st, LebesgueOrder &lo,
//                                       DoubledGaugeField &U,
//                                       const FermionField &in,
//                                       FermionField &out, int dag)
//{
//  GRID_TRACE("DhopSerial");
//  assert((dag == DaggerNo) || (dag == DaggerYes));
//  Compressor compressor(dag);
//  {
//    GRID_TRACE("HaloExchange");
//    st.HaloExchange(in, compressor);
//  }
//
//  int Opt = WilsonKernelsStatic::Opt;
//  if (dag == DaggerYes) {
//    GRID_TRACE("DhopDag");
//    Kernels::DhopDagKernel(Opt,st,U,st.CommBuf(),1,U.oSites(),in,out);
//  } else {
//    GRID_TRACE("Dhop");
//    Kernels::DhopKernel(Opt,st,U,st.CommBuf(),1,U.oSites(),in,out);
//  }
//};
///*Change ends */
//
///*******************************************************************************
// * Conserved current utilities for Wilson fermions, for contracting propagators
// * to make a conserved current sink or inserting the conserved current
// * sequentially.
// ******************************************************************************/
//template <class Impl>
//void WilsonFermion<Impl>::ContractConservedCurrent(PropagatorField &q_in_1,
//                                                   PropagatorField &q_in_2,
//                                                   PropagatorField &q_out,
//                                                   PropagatorField &src,
//                                                   Current curr_type,
//                                                   unsigned int mu)
//{
//  if(curr_type != Current::Vector)
//  {
//    std::cout << GridLogError << "Only the conserved vector current is implemented so far." << std::endl;
//    exit(1);
//  }
//
//  Gamma g5(Gamma::Algebra::Gamma5);
//  conformable(_grid, q_in_1.Grid());
//  conformable(_grid, q_in_2.Grid());
//  conformable(_grid, q_out.Grid());
//  auto UGrid= this->GaugeGrid();
//
//  PropagatorField tmp_shifted(UGrid);
//  PropagatorField g5Lg5(UGrid);
//  PropagatorField R(UGrid);
//  PropagatorField gmuR(UGrid);
//
//    Gamma::Algebra Gmu [] = {
//    Gamma::Algebra::GammaX,
//    Gamma::Algebra::GammaY,
//    Gamma::Algebra::GammaZ,
//    Gamma::Algebra::GammaT,
//  };
//  Gamma gmu=Gamma(Gmu[mu]);
//
//  g5Lg5=g5*q_in_1*g5;
//  tmp_shifted=Cshift(q_in_2,mu,1);
//  Impl::multLinkField(R,this->Umu,tmp_shifted,mu);
//  gmuR=gmu*R;
//
//  q_out=adj(g5Lg5)*R;
//  q_out-=adj(g5Lg5)*gmuR;
//
//  tmp_shifted=Cshift(q_in_1,mu,1);
//  Impl::multLinkField(g5Lg5,this->Umu,tmp_shifted,mu);
//  g5Lg5=g5*g5Lg5*g5;
//  R=q_in_2;
//  gmuR=gmu*R;
//
//  q_out-=adj(g5Lg5)*R;
//  q_out-=adj(g5Lg5)*gmuR;
//}
//
template <class Impl>
void WilsonFermion<Impl>::SeqConservedCurrent(PropagatorField &q_in,
                                              PropagatorField &q_out,
                                              PropagatorField &src,
                                              Current curr_type,
                                              unsigned int mu,
                                              unsigned int tmin,
                                              unsigned int tmax,
					      ComplexField &lattice_cmplx)
{
  if(curr_type != Current::Vector)
  {
    std::cout << GridLogError << "Only the conserved vector current is implemented so far." << std::endl;
    exit(1);
  }

  int tshift = (mu == Nd-1) ? 1 : 0;
  unsigned int LLt    = GridDefaultLatt()[Tp];
  conformable(_grid, q_in.Grid());
  conformable(_grid, q_out.Grid());
  auto UGrid= this->GaugeGrid();

  PropagatorField tmp(UGrid);
  PropagatorField Utmp(UGrid);
  PropagatorField L(UGrid);
  PropagatorField zz (UGrid);
  zz=Zero();
  LatticeInteger lcoor(UGrid); LatticeCoordinate(lcoor,Nd-1);

    Gamma::Algebra Gmu [] = {
    Gamma::Algebra::GammaX,
    Gamma::Algebra::GammaY,
    Gamma::Algebra::GammaZ,
    Gamma::Algebra::GammaT,
  };
  Gamma gmu=Gamma(Gmu[mu]);

  tmp = Cshift(q_in,mu,1);
  Impl::multLinkField(Utmp,this->Umu,tmp,mu);
  tmp = ( Utmp*lattice_cmplx - gmu*Utmp*lattice_cmplx ); // Forward hop
  tmp = where((lcoor>=tmin),tmp,zz); // Mask the time
//  q_out = where((lcoor<=tmax),tmp,zz); // Position of current complicated
//
//  tmp = q_in *lattice_cmplx;
//  tmp = Cshift(tmp,mu,-1);
//  Impl::multLinkField(Utmp,this->Umu,tmp,mu+Nd); // Adjoint link
//  tmp = -( Utmp + gmu*Utmp );
//  // Mask the time
//  if (tmax == LLt - 1 && tshift == 1){ // quick fix to include timeslice 0 if tmax + tshift is over the last timeslice
//    unsigned int t0 = 0;
//    tmp = where(((lcoor==t0) || (lcoor>=tmin+tshift)),tmp,zz);
//  } else {
//    tmp = where((lcoor>=tmin+tshift),tmp,zz);
//  }
//  q_out+= where((lcoor<=tmax+tshift),tmp,zz); // Position of current complicated
}

template class WilsonFermion<WilsonImplD>; 

NAMESPACE_END(Grid);