CPPLapack Code

//=============================================================================
/*! drovector*dssmatrix operator */
inline _drovector operator*(const drovector& vec, const dssmatrix& mat)
{
#ifdef  CPPL_VERBOSE
  std::cerr << "# [MARK] operator*(const drovector&, const dssmatrix&)" << std::endl;
#endif//CPPL_VERBOSE
  
#ifdef  CPPL_DEBUG
  if(vec.L!=mat.N){
    std::cerr << "[ERROR] operator*(const drovector&, const dssmatrix&)" << std::endl
              << "These vector and matrix can not make a product." << std::endl
              << "Your input was (" << vec.L << ") * (" << mat.N << "x" << mat.N << ")." << std::endl;
    exit(1);
  }
#endif//CPPL_DEBUG
  
  drovector newvec(mat.N);
  newvec.zero();
  
  for(int c=0; c<mat.VOL; c++){
    newvec(mat.Indx[c]) +=mat.Array[c]*vec(mat.Jndx[c]);
    if(mat.Indx[c]!=mat.Jndx[c]){
      newvec(mat.Jndx[c]) +=mat.Array[c]*vec(mat.Indx[c]);
    }
  }
  
  return _(newvec);
}