dense_matrix_base.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2024 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner

// This library is free software; you can 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.

// This library 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
// Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA



#ifndef LIBMESH_DENSE_MATRIX_BASE_H
#define LIBMESH_DENSE_MATRIX_BASE_H

// Local Includes
#include "libmesh/libmesh_common.h"
#include "libmesh/compare_types.h"
#include "libmesh/int_range.h"

// C++ includes

namespace libMesh
{

// Forward declarations
template <typename T> class DenseVectorBase;
template <typename T> class DenseVector;

template<typename T>
class DenseMatrixBase
{

protected:
  DenseMatrixBase(const unsigned int new_m=0,
                  const unsigned int new_n=0) : _m(new_m), _n(new_n) {}

public:
  DenseMatrixBase (DenseMatrixBase &&) = default;
  DenseMatrixBase (const DenseMatrixBase &) = default;
  DenseMatrixBase & operator= (const DenseMatrixBase &) = default;
  DenseMatrixBase & operator= (DenseMatrixBase &&) = default;
  virtual ~DenseMatrixBase() = default;

  virtual void zero() = 0;

  virtual T el(const unsigned int i,
               const unsigned int j) const = 0;

  virtual T & el(const unsigned int i,
                 const unsigned int j) = 0;

  virtual void left_multiply (const DenseMatrixBase<T> & M2) = 0;

  virtual void right_multiply (const DenseMatrixBase<T> & M3) = 0;

  unsigned int m() const { return _m; }

  unsigned int n() const { return _n; }

  void print(std::ostream & os = libMesh::out) const;

  friend std::ostream & operator << (std::ostream & os, const DenseMatrixBase<T> & m)
  {
    m.print(os);
    return os;
  }

  void print_scientific(std::ostream & os, unsigned precision=8) const;

  template <typename T2, typename T3>
  typename boostcopy::enable_if_c<
    ScalarTraits<T2>::value, void >::type
  add (const T2 factor,
       const DenseMatrixBase<T3> & mat);

  DenseVector<T> diagonal() const;

protected:

  static void multiply (DenseMatrixBase<T> & M1,
                        const DenseMatrixBase<T> & M2,
                        const DenseMatrixBase<T> & M3);

  void condense(const unsigned int i,
                const unsigned int j,
                const T val,
                DenseVectorBase<T> & rhs);

  unsigned int _m;

  unsigned int _n;
};







template<typename T>
template<typename T2, typename T3>
inline
typename boostcopy::enable_if_c<
  ScalarTraits<T2>::value, void >::type
DenseMatrixBase<T>::add (const T2 factor,
                         const DenseMatrixBase<T3> & mat)
{
  libmesh_assert_equal_to (this->m(), mat.m());
  libmesh_assert_equal_to (this->n(), mat.n());

  for (auto j : make_range(this->n()))
    for (auto i : make_range(this->m()))
      this->el(i,j) += factor*mat.el(i,j);
}


} // namespace libMesh

#endif // LIBMESH_DENSE_MATRIX_BASE_H