diagonal_matrix.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2016 - 2017 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------

#ifndef dealii__diagonal_matrix_h
#define dealii__diagonal_matrix_h


#include <deal.II/lac/vector.h>

DEAL_II_NAMESPACE_OPEN

template <typename VectorType=Vector<double> >
class DiagonalMatrix : public Subscriptor
{
public:
  typedef typename VectorType::value_type value_type;
  typedef typename VectorType::size_type size_type;

  DiagonalMatrix();

  void reinit (const VectorType &vec);

  void compress (VectorOperation::values operation);

  VectorType &get_vector();

  void clear();

  const VectorType &get_vector() const;

  size_type m () const;

  size_type n () const;

  value_type operator()(const size_type i,
                        const size_type j) const;

  value_type &operator()(const size_type i,
                         const size_type j);

  template <typename number2>
  void add (const size_type  row,
            const size_type  n_cols,
            const size_type *col_indices,
            const number2   *values,
            const bool       elide_zero_values = true,
            const bool       col_indices_are_sorted = false);

  void add (const size_type i,
            const size_type j,
            const value_type value);

  void vmult (VectorType       &dst,
              const VectorType &src) const;

  void Tvmult (VectorType       &dst,
               const VectorType &src) const;

  void vmult_add (VectorType       &dst,
                  const VectorType &src) const;

  void Tvmult_add (VectorType       &dst,
                   const VectorType &src) const;

  std::size_t memory_consumption () const;

private:
  VectorType diagonal;
};

/* ---------------------------------- Inline functions ------------------- */

#ifndef DOXYGEN

template <typename VectorType>
DiagonalMatrix<VectorType>::DiagonalMatrix()
  :
  Subscriptor()
{}



template <typename VectorType>
void
DiagonalMatrix<VectorType>::clear()
{
  diagonal.reinit(0);
}



template <typename VectorType>
std::size_t
DiagonalMatrix<VectorType>::memory_consumption () const
{
  return diagonal.memory_consumption();
}



template <typename VectorType>
void
DiagonalMatrix<VectorType>::reinit(const VectorType &vec)
{
  diagonal = vec;
}



template <typename VectorType>
void
DiagonalMatrix<VectorType>::compress (VectorOperation::values operation)
{
  diagonal.compress(operation);
}



template <typename VectorType>
VectorType &
DiagonalMatrix<VectorType>::get_vector()
{
  return diagonal;
}



template <typename VectorType>
const VectorType &
DiagonalMatrix<VectorType>::get_vector() const
{
  return diagonal;
}



template <typename VectorType>
typename VectorType::size_type
DiagonalMatrix<VectorType>::m() const
{
  return diagonal.size();
}



template <typename VectorType>
typename VectorType::size_type
DiagonalMatrix<VectorType>::n() const
{
  return diagonal.size();
}



template <typename VectorType>
typename VectorType::value_type
DiagonalMatrix<VectorType>::operator()(const size_type i,
                                       const size_type j) const
{
  Assert (i==j, ExcIndexRange(j,i,i+1));
  (void) j;
  return diagonal(i);
}



template <typename VectorType>
typename VectorType::value_type &
DiagonalMatrix<VectorType>::operator()(const size_type i,
                                       const size_type j)
{
  Assert (i==j, ExcIndexRange(j,i,i+1));
  (void)j;
  return diagonal(i);
}



template <typename VectorType>
template <typename number2>
void
DiagonalMatrix<VectorType>::add (const size_type  row,
                                 const size_type  n_cols,
                                 const size_type *col_indices,
                                 const number2   *values,
                                 const bool       ,
                                 const bool       )
{
  for (size_type i=0; i<n_cols; ++i)
    if (col_indices[i] == row)
      diagonal(row) += values[i];
}



template <typename VectorType>
void
DiagonalMatrix<VectorType>::add (const size_type i,
                                 const size_type j,
                                 const value_type value)
{
  if (i == j)
    diagonal(i) += value;
}



template <typename VectorType>
void
DiagonalMatrix<VectorType>::vmult(VectorType       &dst,
                                  const VectorType &src) const
{
  dst = src;
  dst.scale(diagonal);
}



template <typename VectorType>
void
DiagonalMatrix<VectorType>::Tvmult(VectorType       &dst,
                                   const VectorType &src) const
{
  vmult(dst, src);
}



template <typename VectorType>
void
DiagonalMatrix<VectorType>::vmult_add(VectorType       &dst,
                                      const VectorType &src) const
{
  VectorType tmp(src);
  tmp.scale(diagonal);
  dst += tmp;
}



template <typename VectorType>
void
DiagonalMatrix<VectorType>::Tvmult_add(VectorType       &dst,
                                       const VectorType &src) const
{
  vmult_add(dst, src);
}


#endif

DEAL_II_NAMESPACE_CLOSE

#endif