#include <dense_submatrix.h>

Inheritance diagram for libMesh::DenseSubMatrix< T >:

Public Member Functions
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
unsigned int	n () const
void	print (std::ostream &os=libMesh::out) const
void	print_scientific (std::ostream &os) const
template<typename T2 , typename T3 >
boostcopy::enable_if_c < ScalarTraits< T2 >::value, void >::type	add (const T2 factor, const DenseMatrixBase< T3 > &mat)
Protected Member Functions
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)
Protected Attributes
unsigned int	_m
unsigned int	_n
Friends
std::ostream &	operator<< (std::ostream &os, const DenseMatrixBase< T > &m)

Detailed Description

template<typename T>
class libMesh::DenseSubMatrix< T >

Defines a dense submatrix for use in Finite Element-type computations. Useful for storing element stiffness matrices before summation into a global matrix, particularly when you have systems of equations.

Author:: Benjamin S. Kirk, 2003

Definition at line 46 of file dense_submatrix.h.

Member Function Documentation

template<typename T >

template<typename T2 , typename T3 >

boostcopy::enable_if_c< ScalarTraits< T2 >::value, void >::type libMesh::DenseMatrixBase< T >::add	(	const T2	factor,
		const DenseMatrixBase< T3 > &	mat
	)		`[inline, inherited]`

Adds factor to every element in the matrix. This should only work if T += T2 * T3 is valid C++ and if T2 is scalar. Return type is void

Definition at line 184 of file dense_matrix_base.h.

References libMesh::DenseMatrixBase< T >::el(), libMesh::DenseMatrixBase< T >::m(), and libMesh::DenseMatrixBase< T >::n().

{
  libmesh_assert_equal_to (this->m(), mat.m());
  libmesh_assert_equal_to (this->n(), mat.n());

  for (unsigned int j=0; j<this->n(); j++)
    for (unsigned int i=0; i<this->m(); i++)
      this->el(i,j) += factor*mat.el(i,j);
}

template<typename T>

void libMesh::DenseMatrixBase< T >::condense	(	const unsigned int	i,
		const unsigned int	j,
		const T	val,
		DenseVectorBase< T > &	rhs
	)		`[protected, inherited]`

Condense-out the (i,j) entry of the matrix, forcing it to take on the value val. This is useful in numerical simulations for applying boundary conditions. Preserves the symmetry of the matrix.

Definition at line 58 of file dense_matrix_base.C.

References libMesh::DenseVectorBase< T >::el(), and libMesh::DenseVectorBase< T >::size().

{
  libmesh_assert_equal_to (this->_m, rhs.size());
  libmesh_assert_equal_to (iv, jv);


  // move the known value into the RHS
  // and zero the column
  for (unsigned int i=0; i<this->m(); i++)
    {
      rhs.el(i) -= this->el(i,jv)*val;
      this->el(i,jv) = 0.;
    }

  // zero the row
  for (unsigned int j=0; j<this->n(); j++)
    this->el(iv,j) = 0.;

  this->el(iv,jv) = 1.;
  rhs.el(iv) = val;

}

template<typename T>

virtual T libMesh::DenseMatrixBase< T >::el	(	const unsigned int	i,
		const unsigned int	j
	)		const `[pure virtual, inherited]`

Returns:: the (i,j) element of the matrix. Since internal data representations may differ, you must redefine this function.

Implemented in libMesh::DenseMatrix< T >, and libMesh::DenseMatrix< Number >.

Referenced by libMesh::DenseMatrixBase< T >::add(), and libMesh::DenseMatrixBase< T >::multiply().

template<typename T>

virtual T& libMesh::DenseMatrixBase< T >::el	(	const unsigned int	i,
		const unsigned int	j
	)		`[pure virtual, inherited]`

Returns:: the (i,j) element of the matrix as a writeable reference. Since internal data representations may differ, you must redefine this function.

Implemented in libMesh::DenseMatrix< T >, and libMesh::DenseMatrix< Number >.

template<typename T>

virtual void libMesh::DenseMatrixBase< T >::left_multiply ( const DenseMatrixBase< T > & M2 ) [pure virtual, inherited]

Performs the operation: (*this) <- M2 * (*this)

Implemented in libMesh::DenseMatrix< T >, and libMesh::DenseMatrix< Number >.

template<typename T>

unsigned int libMesh::DenseMatrixBase< T >::m ( ) const [inline, inherited]

Returns:: the row-dimension of the matrix.

Definition at line 99 of file dense_matrix_base.h.

{ return _m; }

template<typename T>

void libMesh::DenseMatrixBase< T >::multiply	(	DenseMatrixBase< T > &	M1,
		const DenseMatrixBase< T > &	M2,
		const DenseMatrixBase< T > &	M3
	)		`[protected, inherited]`

Performs the computation M1 = M2 * M3 where: M1 = (m x n) M2 = (m x p) M3 = (p x n)

Definition at line 31 of file dense_matrix_base.C.

References libMesh::DenseMatrixBase< T >::el(), libMesh::DenseMatrixBase< T >::m(), and libMesh::DenseMatrixBase< T >::n().

{
  // Assertions to make sure we have been
  // passed matrices of the correct dimension.
  libmesh_assert_equal_to (M1.m(), M2.m());
  libmesh_assert_equal_to (M1.n(), M3.n());
  libmesh_assert_equal_to (M2.n(), M3.m());

  const unsigned int m_s = M2.m();
  const unsigned int p_s = M2.n();
  const unsigned int n_s = M1.n();

  // Do it this way because there is a
  // decent chance (at least for constraint matrices)
  // that M3(k,j) = 0. when right-multiplying.
  for (unsigned int k=0; k<p_s; k++)
    for (unsigned int j=0; j<n_s; j++)
      if (M3.el(k,j) != 0.)
        for (unsigned int i=0; i<m_s; i++)
          M1.el(i,j) += M2.el(i,k) * M3.el(k,j);
}

template<typename T>

unsigned int libMesh::DenseMatrixBase< T >::n ( ) const [inline, inherited]

Returns:: the column-dimension of the matrix.

Definition at line 104 of file dense_matrix_base.h.

{ return _n; }

template<typename T >

void libMesh::DenseMatrixBase< T >::print ( std::ostream & os = libMesh::out ) const [inherited]

Pretty-print the matrix, by default to libMesh::out.

Definition at line 128 of file dense_matrix_base.C.

{
  for (unsigned int i=0; i<this->m(); i++)
    {
      for (unsigned int j=0; j<this->n(); j++)
        os << std::setw(8)
           << this->el(i,j) << " ";

      os << std::endl;
    }

  return;
}

template<typename T >

void libMesh::DenseMatrixBase< T >::print_scientific ( std::ostream & os ) const [inherited]

Prints the matrix entries with more decimal places in scientific notation.

Definition at line 86 of file dense_matrix_base.C.

{
#ifndef LIBMESH_BROKEN_IOSTREAM

  // save the initial format flags
  std::ios_base::fmtflags os_flags = os.flags();

  // Print the matrix entries.
  for (unsigned int i=0; i<this->m(); i++)
    {
      for (unsigned int j=0; j<this->n(); j++)
        os << std::setw(15)
           << std::scientific
           << std::setprecision(8)
           << this->el(i,j) << " ";

      os << std::endl;
    }

  // reset the original format flags
  os.flags(os_flags);

#else

  // Print the matrix entries.
  for (unsigned int i=0; i<this->m(); i++)
    {
      for (unsigned int j=0; j<this->n(); j++)
        os << std::setprecision(8)
           << this->el(i,j)
           << " ";

      os << std::endl;
    }


#endif
}