libdeal.ii-dev 8.4.2-2+b1 / usr / include / deal.II / lac / pointer_matrix.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2002 - 2015 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__pointer_matrix_h
#define dealii__pointer_matrix_h

#include <deal.II/base/subscriptor.h>
#include <deal.II/base/smartpointer.h>
#include <deal.II/lac/vector.h>
#include <deal.II/lac/vector_memory.h>

DEAL_II_NAMESPACE_OPEN

template<typename VectorType> class VectorMemory;

class IdentityMatrix;
template <typename number> class FullMatrix;
template <typename number> class LAPACKFullMatrix;
template <typename number> class SparseMatrix;
template <typename number> class BlockSparseMatrix;
template <typename number> class SparseMatrixEZ;
template <typename number> class BlockSparseMatrixEZ;
template <typename number> class TridiagonalMatrix;
template <typename number, typename BlockVectorType> class BlockMatrixArray;

/*! @addtogroup Matrix2
 *@{
 */

/**
 * Abstract class for use in iterations.  This class provides the interface
 * required by LAC solver classes. It allows to use different concrete matrix
 * classes in the same context, as long as they apply to the same vector
 * class.
 *
 * @author Guido Kanschat, 2000, 2001, 2002
 */
template<typename VectorType>
class PointerMatrixBase : public Subscriptor
{
public:
  /**
   * Value type of this matrix. since the matrix itself is unknown, we take
   * the value type of the vector. Therefore, matrix entries must be
   * convertible to vector entries.
   *
   * This was defined to make this matrix a possible template argument to
   * BlockMatrixArray.
   */
  typedef typename VectorType::value_type value_type;

  /**
   * Virtual destructor.  Does nothing except making sure that the destructor
   * of any derived class is called whenever a pointer-to-base-class object is
   * destroyed.
   */
  virtual ~PointerMatrixBase ();

  /**
   * Reset the object to its original state.
   */
  virtual void clear () = 0;

  /**
   * Matrix-vector product.
   */
  virtual void vmult (VectorType       &dst,
                      const VectorType &src) const = 0;

  /**
   * Transposed matrix-vector product.
   */
  virtual void Tvmult (VectorType       &dst,
                       const VectorType &src) const = 0;

  /**
   * Matrix-vector product, adding to <tt>dst</tt>.
   */
  virtual void vmult_add (VectorType       &dst,
                          const VectorType &src) const = 0;

  /**
   * Transposed matrix-vector product, adding to <tt>dst</tt>.
   */
  virtual void Tvmult_add (VectorType       &dst,
                           const VectorType &src) const = 0;
};


/**
 * A pointer to be used as a matrix.  This class stores a pointer to a matrix
 * and can be used as a matrix itself in iterative methods.
 *
 * The main purpose for the existence of this class is its base class, which
 * only has a vector as template argument. Therefore, this interface provides
 * an abstract base class for matrices.
 *
 * @author Guido Kanschat 2000, 2001, 2002
 */
template<typename MatrixType, typename VectorType>
class PointerMatrix : public PointerMatrixBase<VectorType>
{
public:
  /**
   * Constructor.  The pointer in the argument is stored in this class. As
   * usual, the lifetime of <tt>*M</tt> must be longer than the one of the
   * PointerMatrix.
   *
   * If <tt>M</tt> is zero, no matrix is stored.
   */
  PointerMatrix (const MatrixType *M=0);

  /**
   * Constructor.
   *
   * This class internally stores a pointer to a matrix via a SmartPointer
   * object. The SmartPointer class allows to associate a name with the object
   * pointed to that identifies the object that has the pointer, in order to
   * identify objects that still refer to the object pointed to. The @p name
   * argument to this function is used to this end, i.e., you can in essence
   * assign a name to the current PointerMatrix object.
   */
  PointerMatrix(const char *name);

  /**
   * Constructor. <tt>M</tt> points to a matrix which must live longer than
   * the PointerMatrix.
   *
   * This class internally stores a pointer to a matrix via a SmartPointer
   * object. The SmartPointer class allows to associate a name with the object
   * pointed to that identifies the object that has the pointer, in order to
   * identify objects that still refer to the object pointed to. The @p name
   * argument to this function is used to this end, i.e., you can in essence
   * assign a name to the current PointerMatrix object.
   */
  PointerMatrix(const MatrixType *M,
                const char *name);

  // Use doc from base class
  virtual void clear();

  /**
   * Return whether the object is empty.
   */
  bool empty () const;

  /**
   * Assign a new matrix pointer. Deletes the old pointer and releases its
   * matrix.
   * @see SmartPointer
   */
  const PointerMatrix &operator= (const MatrixType *M);

  /**
   * Matrix-vector product.
   */
  virtual void vmult (VectorType       &dst,
                      const VectorType &src) const;

  /**
   * Transposed matrix-vector product.
   */
  virtual void Tvmult (VectorType       &dst,
                       const VectorType &src) const;

  /**
   * Matrix-vector product, adding to <tt>dst</tt>.
   */
  virtual void vmult_add (VectorType       &dst,
                          const VectorType &src) const;

  /**
   * Transposed matrix-vector product, adding to <tt>dst</tt>.
   */
  virtual void Tvmult_add (VectorType       &dst,
                           const VectorType &src) const;

private:
  /**
   * The pointer to the actual matrix.
   */
  SmartPointer<const MatrixType,PointerMatrix<MatrixType,VectorType> > m;
};


/**
 * A pointer to be used as a matrix.  This class stores a pointer to a matrix
 * and can be used as a matrix itself in iterative methods.
 *
 * The main purpose for the existence of this class is its base class, which
 * only has a vector as template argument. Therefore, this interface provides
 * an abstract base class for matrices.
 *
 * This class differs form PointerMatrix by its additional VectorMemory object
 * and by the fact that it implements the functions vmult_add() and
 * Tvmult_add() only using vmult() and Tvmult() of the MatrixType.
 *
 * @author Guido Kanschat 2006
 */
template<typename MatrixType, typename VectorType>
class PointerMatrixAux : public PointerMatrixBase<VectorType>
{
public:
  /**
   * Constructor.  The pointer in the argument is stored in this class. As
   * usual, the lifetime of <tt>*M</tt> must be longer than the one of the
   * PointerMatrixAux.
   *
   * If <tt>M</tt> is zero, no matrix is stored.
   *
   * If <tt>mem</tt> is zero, then GrowingVectorMemory is used.
   */
  PointerMatrixAux (VectorMemory<VectorType> *mem = 0,
                    const MatrixType         *M = 0);

  /**
   * Constructor not using a matrix.
   *
   * This class internally stores a pointer to a matrix via a SmartPointer
   * object. The SmartPointer class allows to associate a name with the object
   * pointed to that identifies the object that has the pointer, in order to
   * identify objects that still refer to the object pointed to. The @p name
   * argument to this function is used to this end, i.e., you can in essence
   * assign a name to the current PointerMatrix object.
   */
  PointerMatrixAux(VectorMemory<VectorType> *mem,
                   const char               *name);

  /**
   * Constructor. <tt>M</tt> points to a matrix which must live longer than
   * the PointerMatrixAux.
   *
   * This class internally stores a pointer to a matrix via a SmartPointer
   * object. The SmartPointer class allows to associate a name with the object
   * pointed to that identifies the object that has the pointer, in order to
   * identify objects that still refer to the object pointed to. The @p name
   * argument to this function is used to this end, i.e., you can in essence
   * assign a name to the current PointerMatrix object.
   */
  PointerMatrixAux(VectorMemory<VectorType> *mem,
                   const MatrixType         *M,
                   const char               *name);

  // Use doc from base class
  virtual void clear();

  /**
   * Return whether the object is empty.
   */
  bool empty () const;

  /**
   * Assign a new VectorMemory object for getting auxiliary vectors.
   */
  void set_memory(VectorMemory<VectorType> *mem);

  /**
   * Assign a new matrix pointer. Deletes the old pointer and releases its
   * matrix.
   * @see SmartPointer
   */
  const PointerMatrixAux &operator= (const MatrixType *M);

  /**
   * Matrix-vector product.
   */
  virtual void vmult (VectorType       &dst,
                      const VectorType &src) const;

  /**
   * Transposed matrix-vector product.
   */
  virtual void Tvmult (VectorType       &dst,
                       const VectorType &src) const;

  /**
   * Matrix-vector product, adding to <tt>dst</tt>.
   */
  virtual void vmult_add (VectorType       &dst,
                          const VectorType &src) const;

  /**
   * Transposed matrix-vector product, adding to <tt>dst</tt>.
   */
  virtual void Tvmult_add (VectorType       &dst,
                           const VectorType &src) const;

private:
  /**
   * The backup memory if none was provided.
   */
  mutable GrowingVectorMemory<VectorType> my_memory;

  /**
   * Object for getting the auxiliary vector.
   */
  mutable SmartPointer<VectorMemory<VectorType>,PointerMatrixAux<MatrixType,VectorType> > mem;

  /**
   * The pointer to the actual matrix.
   */
  SmartPointer<const MatrixType,PointerMatrixAux<MatrixType,VectorType> > m;
};



/**
 * Implement matrix multiplications for a vector using the PointerMatrixBase
 * functionality. Objects of this class can be used in block matrices.
 *
 * Implements a matrix with image dimension 1 by using the scalar product
 * (#vmult()) and scalar multiplication (#Tvmult()) functions of the Vector
 * class.
 *
 * @author Guido Kanschat, 2006
 */
template <typename number>
class PointerMatrixVector : public PointerMatrixBase<Vector<number> >
{
public:
  /**
   * Constructor.  The pointer in the argument is stored in this class. As
   * usual, the lifetime of <tt>*M</tt> must be longer than the one of the
   * PointerMatrix.
   *
   * If <tt>M</tt> is zero, no matrix is stored.
   */
  PointerMatrixVector (const Vector<number> *M=0);

  /**
   * Constructor.
   *
   * This class internally stores a pointer to a matrix via a SmartPointer
   * object. The SmartPointer class allows to associate a name with the object
   * pointed to that identifies the object that has the pointer, in order to
   * identify objects that still refer to the object pointed to. The @p name
   * argument to this function is used to this end, i.e., you can in essence
   * assign a name to the current PointerMatrix object.
   */
  PointerMatrixVector (const char *name);

  /**
   * Constructor. <tt>M</tt> points to a matrix which must live longer than
   * the PointerMatrix.
   *
   * This class internally stores a pointer to a matrix via a SmartPointer
   * object. The SmartPointer class allows to associate a name with the object
   * pointed to that identifies the object that has the pointer, in order to
   * identify objects that still refer to the object pointed to. The @p name
   * argument to this function is used to this end, i.e., you can in essence
   * assign a name to the current PointerMatrix object.
   */
  PointerMatrixVector (const Vector<number> *M,
                       const char *name);

  // Use doc from base class
  virtual void clear();

  /**
   * Return whether the object is empty.
   */
  bool empty () const;

  /**
   * Assign a new matrix pointer. Deletes the old pointer and releases its
   * matrix.
   * @see SmartPointer
   */
  const PointerMatrixVector &operator= (const Vector<number> *M);

  /**
   * Matrix-vector product, actually the scalar product of <tt>src</tt> and
   * the vector representing this matrix.
   *
   * The dimension of <tt>dst</tt> is 1, while that of <tt>src</tt> is the
   * size of the vector representing this matrix.
   */
  virtual void vmult (Vector<number> &dst,
                      const Vector<number> &src) const;

  /**
   * Transposed matrix-vector product, actually the multiplication of the
   * vector representing this matrix with <tt>src(0)</tt>.
   *
   * The dimension of <tt>src</tt> is 1, while that of <tt>dst</tt> is the
   * size of the vector representing this matrix.
   */
  virtual void Tvmult (Vector<number> &dst,
                       const Vector<number> &src) const;

  /**
   * Matrix-vector product, adding to <tt>dst</tt>.
   *
   * The dimension of <tt>dst</tt> is 1, while that of <tt>src</tt> is the
   * size of the vector representing this matrix.
   */
  virtual void vmult_add (Vector<number> &dst,
                          const Vector<number> &src) const;

  /**
   * Transposed matrix-vector product, adding to <tt>dst</tt>.
   *
   * The dimension of <tt>src</tt> is 1, while that of <tt>dst</tt> is the
   * size of the vector representing this matrix.
   */
  virtual void Tvmult_add (Vector<number> &dst,
                           const Vector<number> &src) const;

private:
  /**
   * The pointer to the actual matrix.
   */
  SmartPointer<const Vector<number>,PointerMatrixVector<number> > m;
};



/**
 * This function helps you creating a PointerMatrixBase object if you do not
 * want to provide the full template arguments of PointerMatrix or
 * PointerMatrixAux.
 *
 * Note that this function by default creates a PointerMatrixAux, emulating
 * the functions <tt>vmult_add</tt> and <tt>Tvmult_add</tt>, using an
 * auxiliary vector. It is overloaded for the library matrix classes
 * implementing these functions themselves. If you have such a class, you
 * should overload the function in order to save memory and time.
 *
 * The result is a PointerMatrixBase* pointing to <tt>matrix</tt>. The
 * <tt>VectorType</tt> argument is a dummy just used to determine the template
 * arguments.
 *
 * @relates PointerMatrixBase @relates PointerMatrixAux
 */
template <typename VectorType, typename MatrixType>
inline
PointerMatrixBase<VectorType> *
new_pointer_matrix_base(MatrixType &matrix, const VectorType &, const char *name = "PointerMatrixAux")
{
  return new PointerMatrixAux<MatrixType, VectorType>(0, &matrix, name);
}

/**
 * Specialized version for IdentityMatrix.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename numberv>
PointerMatrixBase<Vector<numberv> > *
new_pointer_matrix_base(const IdentityMatrix &matrix, const Vector<numberv> &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<IdentityMatrix, Vector<numberv> >(&matrix, name);
}


/**
 * Specialized version for FullMatrix.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename numberv, typename numberm>
PointerMatrixBase<Vector<numberv> > *
new_pointer_matrix_base(const FullMatrix<numberm> &matrix, const Vector<numberv> &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<FullMatrix<numberm>, Vector<numberv> >(&matrix, name);
}


/**
 * Specialized version for LAPACKFullMatrix.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename numberv, typename numberm>
PointerMatrixBase<Vector<numberv> > *
new_pointer_matrix_base(const LAPACKFullMatrix<numberm> &matrix, const Vector<numberv> &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<LAPACKFullMatrix<numberm>, Vector<numberv> >(&matrix, name);
}


/**
 * Specialized version for SparseMatrix.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename numberv, typename numberm>
PointerMatrixBase<Vector<numberv> > *
new_pointer_matrix_base(const SparseMatrix<numberm> &matrix, const Vector<numberv> &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<SparseMatrix<numberm>, Vector<numberv> >(&matrix, name);
}


/**
 * Specialized version for BlockSparseMatrix.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename VectorType, typename numberm>
PointerMatrixBase<VectorType> *
new_pointer_matrix_base(const BlockSparseMatrix<numberm> &matrix, const VectorType &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<BlockSparseMatrix<numberm>, VectorType>(&matrix, name);
}


/**
 * Specialized version for SparseMatrixEZ.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename numberv, typename numberm>
PointerMatrixBase<Vector<numberv> > *
new_pointer_matrix_base(const SparseMatrixEZ<numberm> &matrix, const Vector<numberv> &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<SparseMatrixEZ<numberm>, Vector<numberv> >(&matrix, name);
}


/**
 * Specialized version for BlockSparseMatrixEZ.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename VectorType, typename numberm>
PointerMatrixBase<VectorType> *
new_pointer_matrix_base(const BlockSparseMatrixEZ<numberm> &matrix, const VectorType &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<BlockSparseMatrixEZ<numberm>, VectorType>(&matrix, name);
}


/**
 * Specialized version for BlockMatrixArray.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename numberv, typename numberm, typename BLOCK_VectorType>
PointerMatrixBase<BLOCK_VectorType> *
new_pointer_matrix_base(const BlockMatrixArray<numberm,BLOCK_VectorType> &matrix, const BLOCK_VectorType &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<BlockMatrixArray<numberm,BLOCK_VectorType>, BlockVector<numberv> >(&matrix, name);
}


/**
 * Specialized version for TridiagonalMatrix.
 *
 * @relates PointerMatrixBase @relates PointerMatrix
 */
template <typename numberv, typename numberm>
PointerMatrixBase<Vector<numberv> > *
new_pointer_matrix_base(const TridiagonalMatrix<numberm> &matrix, const Vector<numberv> &, const char *name = "PointerMatrix")
{
  return new PointerMatrix<TridiagonalMatrix<numberm>, Vector<numberv> >(&matrix, name);
}



/*@}*/
//---------------------------------------------------------------------------

template<typename VectorType>
inline
PointerMatrixBase<VectorType>::~PointerMatrixBase ()
{}



//----------------------------------------------------------------------//


template<typename MatrixType, typename VectorType>
PointerMatrix<MatrixType, VectorType>::PointerMatrix (const MatrixType *M)
  : m(M, typeid(*this).name())
{}


template<typename MatrixType, typename VectorType>
PointerMatrix<MatrixType, VectorType>::PointerMatrix (const char *name)
  : m(0, name)
{}


template<typename MatrixType, typename VectorType>
PointerMatrix<MatrixType, VectorType>::PointerMatrix (const MatrixType *M,
                                                      const char       *name)
  : m(M, name)
{}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrix<MatrixType, VectorType>::clear ()
{
  m = 0;
}


template<typename MatrixType, typename VectorType>
inline const PointerMatrix<MatrixType, VectorType> &
PointerMatrix<MatrixType, VectorType>::operator= (const MatrixType *M)
{
  m = M;
  return *this;
}


template<typename MatrixType, typename VectorType>
inline bool
PointerMatrix<MatrixType, VectorType>::empty () const
{
  if (m == 0)
    return true;
  return m->empty();
}

template<typename MatrixType, typename VectorType>
inline void
PointerMatrix<MatrixType, VectorType>::vmult (VectorType       &dst,
                                              const VectorType &src) const
{
  Assert (m != 0, ExcNotInitialized());
  m->vmult (dst, src);
}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrix<MatrixType, VectorType>::Tvmult (VectorType       &dst,
                                               const VectorType &src) const
{
  Assert (m != 0, ExcNotInitialized());
  m->Tvmult (dst, src);
}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrix<MatrixType, VectorType>::vmult_add (VectorType       &dst,
                                                  const VectorType &src) const
{
  Assert (m != 0, ExcNotInitialized());
  m->vmult_add (dst, src);
}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrix<MatrixType, VectorType>::Tvmult_add (VectorType       &dst,
                                                   const VectorType &src) const
{
  Assert (m != 0, ExcNotInitialized());
  m->Tvmult_add (dst, src);
}



//----------------------------------------------------------------------//


template<typename MatrixType, typename VectorType>
PointerMatrixAux<MatrixType, VectorType>::PointerMatrixAux (VectorMemory<VectorType> *mem,
                                                            const MatrixType *M)
  : mem(mem, typeid(*this).name()),
    m(M, typeid(*this).name())
{
  if (mem == 0) mem = &my_memory;
}


template<typename MatrixType, typename VectorType>
PointerMatrixAux<MatrixType, VectorType>::PointerMatrixAux (VectorMemory<VectorType> *mem,
                                                            const char               *name)
  : mem(mem, name),
    m(0, name)
{
  if (mem == 0) mem = &my_memory;
}


template<typename MatrixType, typename VectorType>
PointerMatrixAux<MatrixType, VectorType>::PointerMatrixAux (VectorMemory<VectorType> *mem,
                                                            const MatrixType         *M,
                                                            const char               *name)
  : mem(mem, name),
    m(M, name)
{
  if (mem == 0) mem = &my_memory;
}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrixAux<MatrixType, VectorType>::clear ()
{
  m = 0;
}


template<typename MatrixType, typename VectorType>
inline const PointerMatrixAux<MatrixType, VectorType> &
PointerMatrixAux<MatrixType, VectorType>::operator= (const MatrixType *M)
{
  m = M;
  return *this;
}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrixAux<MatrixType, VectorType>::set_memory(VectorMemory<VectorType> *M)
{
  mem = M;
  if (mem == 0)
    mem = &my_memory;
}


template<typename MatrixType, typename VectorType>
inline bool
PointerMatrixAux<MatrixType, VectorType>::empty () const
{
  if (m == 0)
    return true;
  return m->empty();
}

template<typename MatrixType, typename VectorType>
inline void
PointerMatrixAux<MatrixType, VectorType>::vmult (VectorType       &dst,
                                                 const VectorType &src) const
{
  if (mem == 0)
    mem = &my_memory;
  Assert (mem != 0, ExcNotInitialized());
  Assert (m != 0, ExcNotInitialized());
  m->vmult (dst, src);
}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrixAux<MatrixType, VectorType>::Tvmult (VectorType       &dst,
                                                  const VectorType &src) const
{
  if (mem == 0)
    mem = &my_memory;
  Assert (mem != 0, ExcNotInitialized());
  Assert (m != 0, ExcNotInitialized());
  m->Tvmult (dst, src);
}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrixAux<MatrixType, VectorType>::vmult_add (VectorType       &dst,
                                                     const VectorType &src) const
{
  if (mem == 0)
    mem = &my_memory;
  Assert (mem != 0, ExcNotInitialized());
  Assert (m != 0, ExcNotInitialized());
  VectorType *v = mem->alloc();
  v->reinit(dst);
  m->vmult (*v, src);
  dst += *v;
  mem->free(v);
}


template<typename MatrixType, typename VectorType>
inline void
PointerMatrixAux<MatrixType, VectorType>::Tvmult_add (VectorType       &dst,
                                                      const VectorType &src) const
{
  if (mem == 0)
    mem = &my_memory;
  Assert (mem != 0, ExcNotInitialized());
  Assert (m != 0, ExcNotInitialized());
  VectorType *v = mem->alloc();
  v->reinit(dst);
  m->Tvmult (*v, src);
  dst += *v;
  mem->free(v);
}


//----------------------------------------------------------------------//


template<typename number>
PointerMatrixVector<number>::PointerMatrixVector (const Vector<number> *M)
  : m(M, typeid(*this).name())
{}


template<typename number>
PointerMatrixVector<number>::PointerMatrixVector (const char *name)
  : m(0, name)
{}


template<typename number>
PointerMatrixVector<number>::PointerMatrixVector (const Vector<number> *M,
                                                  const char           *name)
  : m(M, name)
{}


template<typename number>
inline void
PointerMatrixVector<number>::clear ()
{
  m = 0;
}


template<typename number>
inline const PointerMatrixVector<number> &
PointerMatrixVector<number>::operator= (const Vector<number> *M)
{
  m = M;
  return *this;
}


template<typename number>
inline bool
PointerMatrixVector<number>::empty () const
{
  if (m == 0)
    return true;
  return m->empty();
}

template<typename number>
inline void
PointerMatrixVector<number>::vmult (Vector<number>       &dst,
                                    const Vector<number> &src) const
{
  Assert (m != 0, ExcNotInitialized());
  Assert (dst.size() == 1, ExcDimensionMismatch(dst.size(), 1));

  dst(0) = *m * src;
}


template<typename number>
inline void
PointerMatrixVector<number>::Tvmult (Vector<number>       &dst,
                                     const Vector<number> &src) const
{
  Assert (m != 0, ExcNotInitialized());
  Assert(src.size() == 1, ExcDimensionMismatch(src.size(), 1));

  dst.equ (src(0), *m);
}


template<typename number>
inline void
PointerMatrixVector<number>::vmult_add (Vector<number>       &dst,
                                        const Vector<number> &src) const
{
  Assert (m != 0, ExcNotInitialized());
  Assert (dst.size() == 1, ExcDimensionMismatch(dst.size(), 1));

  dst(0) += *m * src;
}


template<typename number>
inline void
PointerMatrixVector<number>::Tvmult_add (Vector<number>       &dst,
                                         const Vector<number> &src) const
{
  Assert (m != 0, ExcNotInitialized());
  Assert(src.size() == 1, ExcDimensionMismatch(src.size(), 1));

  dst.add (src(0), *m);
}


DEAL_II_NAMESPACE_CLOSE

#endif