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

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

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

Copyright (C) 2017

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: David Murphy <dmurphy@phys.columbia.edu>

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_Eigen_Dense.h>
#include <Grid/qcd/action/fermion/FermionCore.h>
#include <Grid/qcd/action/fermion/MobiusEOFAFermion.h>

namespace Grid {
namespace QCD {

  /*
  * Dense matrix versions of routines
  */
  template<class Impl>
  void MobiusEOFAFermion<Impl>::MooeeInv(const FermionField& psi, FermionField& chi)
  {
    this->MooeeInternal(psi, chi, DaggerNo, InverseYes);
  }

  template<class Impl>
  void MobiusEOFAFermion<Impl>::MooeeInv_shift(const FermionField& psi, FermionField& chi)
  {
    this->MooeeInternal(psi, chi, DaggerNo, InverseYes);
  }

  template<class Impl>
  void MobiusEOFAFermion<Impl>::MooeeInvDag(const FermionField& psi, FermionField& chi)
  {
    this->MooeeInternal(psi, chi, DaggerYes, InverseYes);
  }

  template<class Impl>
  void MobiusEOFAFermion<Impl>::MooeeInvDag_shift(const FermionField& psi, FermionField& chi)
  {
    this->MooeeInternal(psi, chi, DaggerYes, InverseYes);
  }

  template<class Impl>
  void MobiusEOFAFermion<Impl>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv)
  {
    int Ls = this->Ls;
    int LLs = psi._grid->_rdimensions[0];
    int vol = psi._grid->oSites()/LLs;

    int pm      = this->pm;
    RealD shift = this->shift;
    RealD alpha = this->alpha;
    RealD k     = this->k;
    RealD mq1   = this->mq1;

    chi.checkerboard = psi.checkerboard;

    assert(Ls==LLs);

    Eigen::MatrixXd Pplus  = Eigen::MatrixXd::Zero(Ls,Ls);
    Eigen::MatrixXd Pminus = Eigen::MatrixXd::Zero(Ls,Ls);

    for(int s=0;s<Ls;s++){
        Pplus(s,s)  = this->bee[s];
        Pminus(s,s) = this->bee[s];
    }

    for(int s=0; s<Ls-1; s++){
        Pminus(s,s+1) = -this->cee[s];
    }

    for(int s=0; s<Ls-1; s++){
        Pplus(s+1,s) = -this->cee[s+1];
    }
    Pplus (0,Ls-1) = mq1*this->cee[0];
    Pminus(Ls-1,0) = mq1*this->cee[Ls-1];

    if(shift != 0.0){
      Coeff_t N = 2.0 * ( std::pow(alpha+1.0,Ls) + mq1*std::pow(alpha-1.0,Ls) );
      for(int s=0; s<Ls; ++s){
        if(pm == 1){ Pplus(s,Ls-1) += shift * k * N * std::pow(-1.0,s) * std::pow(alpha-1.0,s) / std::pow(alpha+1.0,Ls+s+1); }
        else{ Pminus(Ls-1-s,Ls-1) -= shift * k * N * std::pow(-1.0,s) * std::pow(alpha-1.0,s) / std::pow(alpha+1.0,Ls+s+1); }
      }
    }

    Eigen::MatrixXd PplusMat ;
    Eigen::MatrixXd PminusMat;

    if(inv){
      PplusMat  = Pplus.inverse();
      PminusMat = Pminus.inverse();
    } else {
      PplusMat  = Pplus;
      PminusMat = Pminus;
    }

    if(dag){
      PplusMat.adjointInPlace();
      PminusMat.adjointInPlace();
    }

    // For the non-vectorised s-direction this is simple

    for(auto site=0; site<vol; site++){

        SiteSpinor     SiteChi;
        SiteHalfSpinor SitePplus;
        SiteHalfSpinor SitePminus;

        for(int s1=0; s1<Ls; s1++){
            SiteChi = zero;
            for(int s2=0; s2<Ls; s2++){
                int lex2 = s2 + Ls*site;
                if(PplusMat(s1,s2) != 0.0){
                    spProj5p(SitePplus,psi[lex2]);
                    accumRecon5p(SiteChi, PplusMat(s1,s2)*SitePplus);
                }
                if(PminusMat(s1,s2) != 0.0){
                    spProj5m(SitePminus, psi[lex2]);
                    accumRecon5m(SiteChi, PminusMat(s1,s2)*SitePminus);
                }
            }
            chi[s1+Ls*site] = SiteChi*0.5;
        }
    }
  }

  #ifdef MOBIUS_EOFA_DPERP_DENSE

    INSTANTIATE_DPERP_MOBIUS_EOFA(GparityWilsonImplF);
    INSTANTIATE_DPERP_MOBIUS_EOFA(GparityWilsonImplD);
    INSTANTIATE_DPERP_MOBIUS_EOFA(WilsonImplF);
    INSTANTIATE_DPERP_MOBIUS_EOFA(WilsonImplD);
    INSTANTIATE_DPERP_MOBIUS_EOFA(ZWilsonImplF);
    INSTANTIATE_DPERP_MOBIUS_EOFA(ZWilsonImplD);

    template void MobiusEOFAFermion<GparityWilsonImplF>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<GparityWilsonImplD>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<WilsonImplF>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<WilsonImplD>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<ZWilsonImplF>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<ZWilsonImplD>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);

    INSTANTIATE_DPERP_MOBIUS_EOFA(GparityWilsonImplFH);
    INSTANTIATE_DPERP_MOBIUS_EOFA(GparityWilsonImplDF);
    INSTANTIATE_DPERP_MOBIUS_EOFA(WilsonImplFH);
    INSTANTIATE_DPERP_MOBIUS_EOFA(WilsonImplDF);
    INSTANTIATE_DPERP_MOBIUS_EOFA(ZWilsonImplFH);
    INSTANTIATE_DPERP_MOBIUS_EOFA(ZWilsonImplDF);

    template void MobiusEOFAFermion<GparityWilsonImplFH>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<GparityWilsonImplDF>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<WilsonImplFH>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<WilsonImplDF>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<ZWilsonImplFH>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);
    template void MobiusEOFAFermion<ZWilsonImplDF>::MooeeInternal(const FermionField& psi, FermionField& chi, int dag, int inv);

  #endif

}}