PETScWrappers::MatrixIterators::const_iterator::Accessor Class Reference

List of all members.

Classes

class  ExcAccessToNonlocalRow
class  ExcBeyondEndOfMatrix

Public Member Functions

 Accessor (const MatrixBase *matrix, const unsigned int row, const unsigned int index)
unsigned int row () const
unsigned int index () const
unsigned int column () const
PetscScalar value () const

Private Member Functions

void visit_present_row ()

Private Attributes

MatrixBasematrix
unsigned int a_row
unsigned int a_index
std_cxx1x::shared_ptr< const
std::vector< unsigned int > > 
colnum_cache
std_cxx1x::shared_ptr< const
std::vector< PetscScalar > > 
value_cache

Friends

class const_iterator

Detailed Description

Accessor class for iterators


Constructor & Destructor Documentation

PETScWrappers::MatrixIterators::const_iterator::Accessor::Accessor ( const MatrixBase matrix,
const unsigned int  row,
const unsigned int  index 
)

Constructor. Since we use accessors only for read access, a const matrix pointer is sufficient.


Member Function Documentation

unsigned int PETScWrappers::MatrixIterators::const_iterator::Accessor::row (  )  const

Row number of the element represented by this object.

unsigned int PETScWrappers::MatrixIterators::const_iterator::Accessor::index (  )  const

Index in row of the element represented by this object.

unsigned int PETScWrappers::MatrixIterators::const_iterator::Accessor::column (  )  const

Column number of the element represented by this object.

PetscScalar PETScWrappers::MatrixIterators::const_iterator::Accessor::value (  )  const

Value of this matrix entry.

void PETScWrappers::MatrixIterators::const_iterator::Accessor::visit_present_row (  )  [private]

Discard the old row caches (they may still be used by other accessors) and generate new ones for the row pointed to presently by this accessor.


Friends And Related Function Documentation

friend class const_iterator [friend]

Make enclosing class a friend.


Member Data Documentation

The matrix accessed.

Current row number.

Current index in row.

std_cxx1x::shared_ptr<const std::vector<unsigned int> > PETScWrappers::MatrixIterators::const_iterator::Accessor::colnum_cache [private]

Cache where we store the column indices of the present row. This is necessary, since PETSc makes access to the elements of its matrices rather hard, and it is much more efficient to copy all column entries of a row once when we enter it than repeatedly asking PETSc for individual ones. This also makes some sense since it is likely that we will access them sequentially anyway.

In order to make copying of iterators/accessor of acceptable performance, we keep a shared pointer to these entries so that more than one accessor can access this data if necessary.

std_cxx1x::shared_ptr<const std::vector<PetscScalar> > PETScWrappers::MatrixIterators::const_iterator::Accessor::value_cache [private]

Similar cache for the values of this row.


The documentation for this class was generated from the following file:

deal.II documentation generated on Mon Nov 23 22:58:31 2009 by doxygen 1.6.1