unitMatrix.hh

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*                                                                             */
/*   This file is part of the C++-library RFFGen.                              */
/*   Copyright 2015 Lars Lubkoll                                               */
/*                                                                             */
/*   RFFGen is free software: you can redistribute it and/or modify            */
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#ifndef RFFGEN_LINEAR_ALGEBRA_UNIT_MATRIX_HH
#define RFFGEN_LINEAR_ALGEBRA_UNIT_MATRIX_HH

#include "../Util/at.hh"
#include "../Util/voider.hh"
#include "../Util/zero.hh"
#include "dimension.hh"
#include "extractRowsAndCols.hh"

namespace RFFGen
{
  namespace LinearAlgebra
  {
    template <class Matrix, class = std::enable_if_t<Checks::isConstantSizeMatrix<Matrix>()> >
    Matrix unitMatrix()
    {
      Matrix A = zero<Matrix>();
      for(int i=0; i<dimension<Matrix>(); ++i) at(A,i,i) = 1;
      return A;
    }

    template <class Matrix, class = std::enable_if_t<!Checks::isConstantSizeMatrix<Matrix>()> >
    Matrix unitMatrix(int rows)
    {
      Matrix A = zero<Matrix>(rows,rows);
      for(int i=0; i<rows; ++i) at(A,i,i) = 1;
      return A;
    }
  }
}

#endif // RFFGEN_LINEAR_ALGEBRA_UNIT_MATRIX_HH