Grid/lib/qcd/action/scalar/ScalarImpl.h

#ifndef SCALAR_IMPL
#define SCALAR_IMPL


namespace Grid {
  //namespace QCD {

template <class S>
class ScalarImplTypes {
 public:
    typedef S Simd;

    template <typename vtype>
    using iImplField = iScalar<iScalar<iScalar<vtype> > >;

    typedef iImplField<Simd> SiteField;
    typedef SiteField        SitePropagator;
    typedef SiteField        SiteComplex;
    
    typedef Lattice<SiteField> Field;
    typedef Field              ComplexField;
    typedef Field              FermionField;
    typedef Field              PropagatorField;
    
    static inline void generate_momenta(Field& P, GridParallelRNG& pRNG){
      gaussian(pRNG, P);
    }

    static inline Field projectForce(Field& P){return P;}

    static inline void update_field(Field& P, Field& U, double ep) {
      U += P*ep;
    }

    static inline RealD FieldSquareNorm(Field& U) {
      return (- sum(trace(U*U))/2.0);
    }

    static inline void HotConfiguration(GridParallelRNG &pRNG, Field &U) {
      gaussian(pRNG, U);
    }

    static inline void TepidConfiguration(GridParallelRNG &pRNG, Field &U) {
      gaussian(pRNG, U);
    }

    static inline void ColdConfiguration(GridParallelRNG &pRNG, Field &U) {
      U = 1.0;
    }
    
    static void MomentumSpacePropagator(Field &out, RealD m)
    {
      GridBase           *grid = out._grid;
      Field              kmu(grid), one(grid);
      const unsigned int nd    = grid->_ndimension;
      std::vector<int>   &l    = grid->_fdimensions;
      
      one = Complex(1.0,0.0);
      out = m*m;
      for(int mu = 0; mu < nd; mu++)
      {
        Real twoPiL = M_PI*2./l[mu];
        
        LatticeCoordinate(kmu,mu);
        kmu = 2.*sin(.5*twoPiL*kmu);
        out = out + kmu*kmu;
      }
      out = one/out;
    }
    
    static void FreePropagator(const Field &in, Field &out,
                               const Field &momKernel)
    {
      FFT   fft((GridCartesian *)in._grid);
      Field inFT(in._grid);
      
      fft.FFT_all_dim(inFT, in, FFT::forward);
      inFT = inFT*momKernel;
      fft.FFT_all_dim(out, inFT, FFT::backward);
    }
    
    static void FreePropagator(const Field &in, Field &out, RealD m)
    {
      Field momKernel(in._grid);
      
      MomentumSpacePropagator(momKernel, m);
      FreePropagator(in, out, momKernel);
    }
    
  };

  template <class S, unsigned int N>
  class ScalarAdjMatrixImplTypes {
  public:
    typedef S Simd;
    typedef QCD::SU<N> Group;
    
    template <typename vtype>
    using iImplField   = iScalar<iScalar<iMatrix<vtype, N>>>;
    template <typename vtype>
    using iImplComplex = iScalar<iScalar<iScalar<vtype>>>;

    typedef iImplField<Simd>   SiteField;
    typedef SiteField          SitePropagator;
    typedef iImplComplex<Simd> SiteComplex;
    
    typedef Lattice<SiteField>   Field;
    typedef Lattice<SiteComplex> ComplexField;
    typedef Field                FermionField;
    typedef Field                PropagatorField;

    static inline void generate_momenta(Field& P, GridParallelRNG& pRNG) {
      Group::GaussianFundamentalLieAlgebraMatrix(pRNG, P);
    }

    static inline Field projectForce(Field& P) {return P;}

    static inline void update_field(Field& P, Field& U, double ep) {
      U += P*ep;
    }

    static inline RealD FieldSquareNorm(Field& U) {
      return (TensorRemove(sum(trace(U*U))).real());
    }

    static inline void HotConfiguration(GridParallelRNG &pRNG, Field &U) {
      Group::GaussianFundamentalLieAlgebraMatrix(pRNG, U);
    }

    static inline void TepidConfiguration(GridParallelRNG &pRNG, Field &U) {
      Group::GaussianFundamentalLieAlgebraMatrix(pRNG, U, 0.01);
    }

    static inline void ColdConfiguration(GridParallelRNG &pRNG, Field &U) {
      U = zero;
    }

  };




  typedef ScalarImplTypes<vReal> ScalarImplR;
  typedef ScalarImplTypes<vRealF> ScalarImplF;
  typedef ScalarImplTypes<vRealD> ScalarImplD;
  typedef ScalarImplTypes<vComplex> ScalarImplCR;
  typedef ScalarImplTypes<vComplexF> ScalarImplCF;
  typedef ScalarImplTypes<vComplexD> ScalarImplCD;
    
  // Hardcoding here the size of the matrices
  typedef ScalarAdjMatrixImplTypes<vComplex,  QCD::Nc> ScalarAdjImplR;
  typedef ScalarAdjMatrixImplTypes<vComplexF, QCD::Nc> ScalarAdjImplF;
  typedef ScalarAdjMatrixImplTypes<vComplexD, QCD::Nc> ScalarAdjImplD;

  template <int Colours > using ScalarNxNAdjImplR = ScalarAdjMatrixImplTypes<vComplex,   Colours >;
  template <int Colours > using ScalarNxNAdjImplF = ScalarAdjMatrixImplTypes<vComplexF,  Colours >;
  template <int Colours > using ScalarNxNAdjImplD = ScalarAdjMatrixImplTypes<vComplexD,  Colours >;
  
  //}
}

#endif