|
dune-istl 2.10
|
Matrix and Vector classes that support a block recursive structure capable of representing the natural structure from Finite Element discretisations. More...

Topics | |
| Block Recursive Iterative Kernels | |
| IO for matrices and vectors. | |
| Provides methods for reading and writing matrices and vectors in various formats. | |
| DenseMatVec | |
Files | |
| file | matrixmatrix.hh |
| provides functions for sparse matrix matrix multiplication. | |
| file | matrixutils.hh |
| Some handy generic functions for ISTL matrices. | |
Enumerations | |
| enum | Dune::BuildMode { Dune::row_wise , Dune::random , Dune::implicit , Dune::unknown } |
| enum | { Dune::SparsityPatternInitializer< T, A, n, m >::do_break =true } |
| enum | { Dune::MatrixInitializer< transpose, T, TA, n, m >::do_break =true } |
| enum | { Dune::MatrixInitializer< 1, T, TA, n, m >::do_break =false } |
| enum | { Dune::EntryAccumulatorFather< T, A, n, m >::do_break =false } |
Functions | |
| block_type & | Dune::ImplicitMatrixBuilder< M_ >::row_object::operator[] (size_type j) const |
| Returns entry in column j. | |
| Dune::ImplicitMatrixBuilder< M_ >::ImplicitMatrixBuilder (Matrix &m) | |
| Creates an ImplicitMatrixBuilder for matrix m. | |
| Dune::ImplicitMatrixBuilder< M_ >::ImplicitMatrixBuilder (Matrix &m, size_type rows, size_type cols, size_type avg_cols_per_row, double overflow_fraction) | |
| Sets up matrix m for implicit construction using the given parameters and creates an ImplicitBmatrixuilder for it. | |
| row_object | Dune::ImplicitMatrixBuilder< M_ >::operator[] (size_type i) const |
| Returns a proxy for entries in row i. | |
| size_type | Dune::ImplicitMatrixBuilder< M_ >::N () const |
| The number of rows in the matrix. | |
| size_type | Dune::ImplicitMatrixBuilder< M_ >::M () const |
| The number of columns in the matrix. | |
| *random access to the rows row_type & | Dune::operator[] (size_type i) |
| *constructor | Dune::RealRowIterator< T >::RealRowIterator (row_type *_p, size_type _i) |
| *empty use with care | Dune::RealRowIterator< T >::!RealRowIterator () |
| Dune::RealRowIterator< T >::RealRowIterator (const RealRowIterator< ValueType > &it) | |
| *return index size_type | Dune::RealRowIterator< T >::index () const |
| std::ptrdiff_t | Dune::RealRowIterator< T >::distanceTo (const RealRowIterator< ValueType > &other) const |
| std::ptrdiff_t | Dune::RealRowIterator< T >::distanceTo (const RealRowIterator< const ValueType > &other) const |
| *equality bool | Dune::RealRowIterator< T >::equals (const RealRowIterator< ValueType > &other) const |
| *equality bool | Dune::RealRowIterator< T >::equals (const RealRowIterator< const ValueType > &other) const |
| template<class T, class A, class A1, class A2, int n, int m, int k> | |
| void | Dune::matMultTransposeMat (BCRSMatrix< FieldMatrix< T, n, k >, A > &res, const BCRSMatrix< FieldMatrix< T, n, m >, A1 > &mat, const BCRSMatrix< FieldMatrix< T, k, m >, A2 > &matt, bool tryHard=false) |
| Calculate product of a sparse matrix with a transposed sparse matrices ( | |
| template<class T, class A, class A1, class A2, int n, int m, int k> | |
| void | Dune::matMultMat (BCRSMatrix< FieldMatrix< T, n, m >, A > &res, const BCRSMatrix< FieldMatrix< T, n, k >, A1 > &mat, const BCRSMatrix< FieldMatrix< T, k, m >, A2 > &matt, bool tryHard=false) |
| Calculate product of two sparse matrices ( | |
| template<class T, class A, class A1, class A2, int n, int m, int k> | |
| void | Dune::transposeMatMultMat (BCRSMatrix< FieldMatrix< T, n, m >, A > &res, const BCRSMatrix< FieldMatrix< T, k, n >, A1 > &mat, const BCRSMatrix< FieldMatrix< T, k, m >, A2 > &matt, bool tryHard=false) |
| Calculate product of a transposed sparse matrix with another sparse matrices ( | |
| template<class M> | |
| auto | Dune::countNonZeros (const M &, typename std::enable_if_t< Dune::IsNumber< M >::value > *sfinae=nullptr) |
| Get the number of nonzero fields in the matrix. | |
| template<class M> | |
| auto | Dune::countNonZeros (const M &matrix, typename std::enable_if_t<!Dune::IsNumber< M >::value > *sfinae=nullptr) |
| static constexpr size_type | Dune::MultiTypeBlockVector< Args >::size () |
| Return the number of non-zero vector entries. | |
| static constexpr size_type | Dune::MultiTypeBlockVector< Args >::N () |
| Number of elements. | |
| size_type | Dune::MultiTypeBlockVector< Args >::dim () const |
| Number of scalar elements. | |
| template<size_type index> | |
| std::tuple_element< index, TupleType >::type & | Dune::MultiTypeBlockVector< Args >::operator[] (const std::integral_constant< size_type, index > indexVariable) |
| Random-access operator. | |
| template<size_type index> | |
| const std::tuple_element< index, TupleType >::type & | Dune::MultiTypeBlockVector< Args >::operator[] (const std::integral_constant< size_type, index > indexVariable) const |
| Const random-access operator. | |
| template<typename T> | |
| void | Dune::MultiTypeBlockVector< Args >::operator= (const T &newval) |
| Assignment operator. | |
| void | Dune::MultiTypeBlockVector< Args >::operator+= (const type &newv) |
| void | Dune::MultiTypeBlockVector< Args >::operator-= (const type &newv) |
| template<class T, std::enable_if_t< IsNumber< T >::value, int > = 0> | |
| void | Dune::MultiTypeBlockVector< Args >::operator*= (const T &w) |
| Multiplication with a scalar. | |
| template<class T, std::enable_if_t< IsNumber< T >::value, int > = 0> | |
| void | Dune::MultiTypeBlockVector< Args >::operator/= (const T &w) |
| Division by a scalar. | |
| field_type | Dune::MultiTypeBlockVector< Args >::operator* (const type &newv) const |
| field_type | Dune::MultiTypeBlockVector< Args >::dot (const type &newv) const |
| auto | Dune::MultiTypeBlockVector< Args >::one_norm () const |
| Compute the 1-norm. | |
| auto | Dune::MultiTypeBlockVector< Args >::one_norm_real () const |
| Compute the simplified 1-norm (uses 1-norm also for complex values). | |
| real_type | Dune::MultiTypeBlockVector< Args >::two_norm2 () const |
| Compute the squared Euclidean norm. | |
| real_type | Dune::MultiTypeBlockVector< Args >::two_norm () const |
| Compute the Euclidean norm. | |
| real_type | Dune::MultiTypeBlockVector< Args >::infinity_norm () const |
| Compute the maximum norm. | |
| real_type | Dune::MultiTypeBlockVector< Args >::infinity_norm_real () const |
| Compute the simplified maximum norm (uses 1-norm for complex values). | |
| template<typename Ta> | |
| void | Dune::MultiTypeBlockVector< Args >::axpy (const Ta &a, const type &y) |
| Axpy operation on this vector (*this += a * y). | |
| template<typename... Args> | |
| std::ostream & | Dune::operator<< (std::ostream &s, const MultiTypeBlockVector< Args... > &v) |
| Send MultiTypeBlockVector to an outstream. | |
Variables | |
| *the type representing the components typedef B | Dune::block_type |
| *the allocator type typedef A | Dune::allocator_type |
| *The type for the index access and the size typedef A::size_type | Dune::size_type |
| *implement row_type with compressed vector typedef Imp::CompressedBlockVectorWindow< B, size_type > | Dune::row_type |
| *brief The unqualified value type typedef std::remove_const< T >::type | Dune::RealRowIterator< T >::ValueType |
| double | Dune::CompressionStatistics< size_type >::avg |
| average number of non-zeroes per row. | |
| size_type | Dune::CompressionStatistics< size_type >::maximum |
| maximum number of non-zeroes per row. | |
| size_type | Dune::CompressionStatistics< size_type >::overflow_total |
| total number of elements written to the overflow area during construction. | |
| double | Dune::CompressionStatistics< size_type >::mem_ratio |
| fraction of wasted memory resulting from non-used overflow area. | |
| Dune::notbuilt =0 | |
| A sparse block matrix with compressed row storage. | |
| Dune::notAllocated =0 | |
| Matrix is not built at all, no memory has been allocated, build mode and size can still be set. | |
| Dune::building =1 | |
| Matrix is currently being built, some memory has been allocated, build mode and size are fixed. | |
| Dune::rowSizesBuilt =2 | |
| The row sizes of the matrix are known. | |
| Dune::built | |
| The matrix structure is fully built. | |
| *empty | Dune::RealRowIterator< T >::constructor |
| Matrix & | Dune::EntryAccumulatorFather< T, A, n, m >::mat |
| Col | Dune::EntryAccumulatorFather< T, A, n, m >::col |
Matrix and Vector classes that support a block recursive structure capable of representing the natural structure from Finite Element discretisations.
The interface of our matrices is designed according to what they represent from a mathematical point of view. The vector classes are representations of vector spaces:







The matrix classes represent linear maps 








| typedef Matrix::block_type Dune::ImplicitMatrixBuilder< M_ >::block_type |
The block_type of the underlying matrix.
| typedef Matrix::ColIterator Dune::EntryAccumulatorFather< T, A, n, m >::Col |
| typedef Matrix::CreateIterator Dune::MatrixInitializer< transpose, T, TA, n, m >::CreateIterator |
| typedef Matrix::CreateIterator Dune::MatrixInitializer< 1, T, TA, n, m >::CreateIterator |
| typedef BCRSMatrix<FieldMatrix<T,n,m>,A>::CreateIterator Dune::SparsityPatternInitializer< T, A, n, m >::CreateIterator |
| using Dune::field_type = typename Imp::BlockTraits<B>::field_type |
| using Dune::FieldTraits< MultiTypeBlockVector< Args... > >::field_type = typename MultiTypeBlockVector<Args...>::field_type |
| using Dune::MultiTypeBlockVector< Args >::field_type = Std::detected_t<std::common_type_t, typename FieldTraits< std::decay_t<Args> >::field_type...> |
The type used for scalars.
Use the std::common_type_t of the Args' field_type and use nonesuch if no implementation of std::common_type is provided for the given field_type arguments.
| typedef BCRSMatrix<FieldMatrix<T,n,m>,A> Dune::EntryAccumulator< T, A, n, m, transpose >::Matrix |
| typedef BCRSMatrix<FieldMatrix<T,n,m>,A> Dune::EntryAccumulator< T, A, n, m, 0 >::Matrix |
| typedef BCRSMatrix<FieldMatrix<T,n,m>,A> Dune::EntryAccumulator< T, A, n, m, 1 >::Matrix |
| typedef BCRSMatrix<FieldMatrix<T,n,m>,A> Dune::EntryAccumulator< T, A, n, m, 2 >::Matrix |
| typedef BCRSMatrix<FieldMatrix<T,n,m>,A> Dune::EntryAccumulatorFather< T, A, n, m >::Matrix |
| typedef M_ Dune::ImplicitMatrixBuilder< M_ >::Matrix |
The underlying matrix.
| typedef Dune::BCRSMatrix<FieldMatrix<T,n,m>,TA> Dune::MatrixInitializer< transpose, T, TA, n, m >::Matrix |
| typedef Dune::BCRSMatrix<Dune::FieldMatrix<T,n,m>,TA> Dune::MatrixInitializer< 1, T, TA, n, m >::Matrix |
| using Dune::FieldTraits< MultiTypeBlockVector< Args... > >::real_type = typename MultiTypeBlockVector<Args...>::real_type |
| using Dune::MultiTypeBlockVector< Args >::real_type = Std::detected_t<std::common_type_t, typename FieldTraits< std::decay_t<Args> >::real_type...> |
| typedef Matrix::RowIterator Dune::EntryAccumulatorFather< T, A, n, m >::Row |
| typedef Matrix::size_type Dune::EntryAccumulator< T, A, n, m, transpose >::size_type |
| typedef Matrix::size_type Dune::EntryAccumulator< T, A, n, m, 0 >::size_type |
| typedef Matrix::size_type Dune::EntryAccumulator< T, A, n, m, 1 >::size_type |
| typedef Matrix::size_type Dune::EntryAccumulator< T, A, n, m, 2 >::size_type |
| typedef Matrix::size_type Dune::ImplicitMatrixBuilder< M_ >::size_type |
The size_type of the underlying matrix.
| typedef Matrix::size_type Dune::MatrixInitializer< transpose, T, TA, n, m >::size_type |
| typedef Matrix::size_type Dune::MatrixInitializer< 1, T, TA, n, m >::size_type |
| using Dune::MultiTypeBlockVector< Args >::size_type = std::size_t |
Type used for vector sizes.
| typedef BCRSMatrix<FieldMatrix<T,n,m>,A>::size_type Dune::SparsityPatternInitializer< T, A, n, m >::size_type |
| typedef BCRSMatrix<typename MatMultMatResult<FieldMatrix<T,n,k>,FieldMatrix<T,k,m> >::type, std::allocator<typename MatMultMatResult<FieldMatrix<T,n,k>,FieldMatrix<T,k,m> >::type> > Dune::MatMultMatResult< BCRSMatrix< FieldMatrix< T, n, k >, A >, BCRSMatrix< FieldMatrix< T, k, m >, A1 > >::type |
| typedef FieldMatrix<T,n,m> Dune::MatMultMatResult< FieldMatrix< T, n, k >, FieldMatrix< T, k, m > >::type |
| typedef MultiTypeBlockVector<Args...> Dune::MultiTypeBlockVector< Args >::type |
own class' type
| typedef BCRSMatrix<typename MatMultMatResult<FieldMatrix<T,n,k>,FieldMatrix<T,k,m> >::type, std::allocator<typename MatMultMatResult<FieldMatrix<T,n,k>,FieldMatrix<T,k,m> >::type> > Dune::TransposedMatMultMatResult< BCRSMatrix< FieldMatrix< T, k, n >, A >, BCRSMatrix< FieldMatrix< T, k, m >, A1 > >::type |
| typedef FieldMatrix<T,n,m> Dune::TransposedMatMultMatResult< FieldMatrix< T, k, n >, FieldMatrix< T, k, m > >::type |
| using std::tuple_element< i, Dune::MultiTypeBlockVector< Args... > >::type = typename std::tuple_element<i, std::tuple<Args...> >::type |
| enum Dune::BuildMode |
| Enumerator | |
|---|---|
| row_wise | Build in a row-wise manner. Rows are built up in sequential order. Size of the row and the column indices are defined. A row can be used as soon as it is initialized. With respect to memory there are two variants of this scheme: (a) number of non-zeroes known in advance (application finite difference schemes), (b) number of non-zeroes not known in advance (application: Sparse LU, ILU(n)). |
| random | Build entries randomly. For general finite element implementations the number of rows n is known, the number of non-zeroes might also be known (e.g. #edges + #nodes for P2) but the size of a row and the indices of a row cannot be defined in sequential order. |
| implicit | Build entries randomly with an educated guess for the number of entries per row. Allows random order generation as in random mode, but row sizes do not need to be given first. Instead an average number of non-zeroes per row is passed to the constructor. Matrix setup is finished with compress(), full data access during build stage is possible. |
| unknown | Build mode not set! |
|
inline |
|
inline |
Axpy operation on this vector (*this += a * y).
| Ta | Type of the scalar 'a' |
|
inline |
Get the number of nonzero fields in the matrix.
This is not the number of nonzero blocks, but the number of non zero scalar entries (on blocklevel 1) if the matrix is viewed as a flat matrix.
For FieldMatrix this is simply the number of columns times the number of rows, for a BCRSMatrix<FieldMatrix<K,n,m>> this is the number of nonzero blocks time n*m.
|
inline |
|
inline |
Number of scalar elements.
|
inline |
|
inline |
|
inline |
|
inline |
|
inline |
|
inline |
Creates an ImplicitMatrixBuilder for matrix m.
|
inline |
Sets up matrix m for implicit construction using the given parameters and creates an ImplicitBmatrixuilder for it.
Using this constructor, you can perform the necessary matrix setup and the creation of the ImplicitMatrixBuilder in a single step. The matrix must still be in the build stage notAllocated, otherwise a BCRSMatrixError will be thrown. For a detailed explanation of the matrix parameters, see BCRSMatrix.
| m | the matrix to be built |
| rows | the number of matrix rows |
| cols | the number of matrix columns |
| avg_cols_per_row | the average number of non-zero columns per row |
| overflow_fraction | the amount of overflow to reserve in the matrix |
|
inline |
|
inline |
Compute the maximum norm.
|
inline |
Compute the simplified maximum norm (uses 1-norm for complex values).
|
inline |
The number of columns in the matrix.
| void Dune::matMultMat | ( | BCRSMatrix< FieldMatrix< T, n, m >, A > & | res, |
| const BCRSMatrix< FieldMatrix< T, n, k >, A1 > & | mat, | ||
| const BCRSMatrix< FieldMatrix< T, k, m >, A2 > & | matt, | ||
| bool | tryHard = false ) |
| void Dune::matMultTransposeMat | ( | BCRSMatrix< FieldMatrix< T, n, k >, A > & | res, |
| const BCRSMatrix< FieldMatrix< T, n, m >, A1 > & | mat, | ||
| const BCRSMatrix< FieldMatrix< T, k, m >, A2 > & | matt, | ||
| bool | tryHard = false ) |
|
inline |
The number of rows in the matrix.
|
inlinestaticconstexpr |
Number of elements.
|
inline |
Compute the 1-norm.
|
inline |
Compute the simplified 1-norm (uses 1-norm also for complex values).
|
inline |
|
inline |
Multiplication with a scalar.
|
inline |
operator for MultiTypeBlockVector += MultiTypeBlockVector operations
|
inline |
operator for MultiTypeBlockVector -= MultiTypeBlockVector operations
|
inline |
Division by a scalar.
| std::ostream & Dune::operator<< | ( | std::ostream & | s, |
| const MultiTypeBlockVector< Args... > & | v ) |
Send MultiTypeBlockVector to an outstream.
|
inline |
Assignment operator.
|
inline |
Returns a proxy for entries in row i.
|
inline |
Returns entry in column j.
|
inline |
Random-access operator.
This method mimics the behavior of normal vector access with square brackets like, e.g., v[5] = 1. The problem is that the return type is different for each value of the argument in the brackets. Therefore we implement a trick using std::integral_constant. To access the first entry of a MultiTypeBlockVector named v write
The name '_0' used here as a static replacement of the integer number zero is arbitrary. Any other variable name can be used. If you don't like the separate variable, you can writee
|
inline |
Const random-access operator.
This is the const version of the random-access operator. See the non-const version for a full explanation of how to use it.
|
inline |
|
inline |
|
inlinestaticconstexpr |
Return the number of non-zero vector entries.
As this is a dense vector data structure, all entries are non-zero, and hence 'size' returns the same number as 'N'.
| void Dune::transposeMatMultMat | ( | BCRSMatrix< FieldMatrix< T, n, m >, A > & | res, |
| const BCRSMatrix< FieldMatrix< T, k, n >, A1 > & | mat, | ||
| const BCRSMatrix< FieldMatrix< T, k, m >, A2 > & | matt, | ||
| bool | tryHard = false ) |
|
inline |
Compute the Euclidean norm.
|
inline |
Compute the squared Euclidean norm.
| * the allocator type typedef A Dune::allocator_type |
| double Dune::CompressionStatistics< size_type >::avg |
average number of non-zeroes per row.
| * the type representing the components typedef B Dune::block_type |
| Dune::building =1 |
Matrix is currently being built, some memory has been allocated, build mode and size are fixed.
| Dune::built |
The matrix structure is fully built.
|
protected |
| * empty Dune::RealRowIterator< T >::constructor |
|
protected |
| size_type Dune::CompressionStatistics< size_type >::maximum |
maximum number of non-zeroes per row.
| double Dune::CompressionStatistics< size_type >::mem_ratio |
fraction of wasted memory resulting from non-used overflow area.
mem_ratio is equal to nonzeros()/(# allocated matrix entries).
| Dune::notAllocated =0 |
Matrix is not built at all, no memory has been allocated, build mode and size can still be set.
| Dune::notbuilt =0 |
A sparse block matrix with compressed row storage.
Implements a block compressed row storage scheme. The block type B can be any type implementing the matrix interface.
Different ways to build up a compressed row storage matrix are supported:
Error checking: no error checking is provided normally. Setting the compile time switch DUNE_ISTL_WITH_CHECKING enables error checking.
Details:
Rows are built up in sequential order. Size of the row and the column indices are defined. A row can be used as soon as it is initialized. With respect to memory there are two variants of this scheme: (a) number of non-zeroes known in advance (application finite difference schemes), (b) number of non-zeroes not known in advance (application: Sparse LU, ILU(n)).
For general finite element implementations the number of rows n is known, the number of non-zeroes might also be known (e.g. #edges + #nodes for P2) but the size of a row and the indices of a row can not be defined in sequential order.
With the 'random scheme` described above, the sparsity pattern has to be determined and stored before the matrix is assembled. This requires a dedicated iteration over the grid elements, which can be costly in terms of time. Also, additional memory is needed to store the pattern before it can be given to the 'random' build mode.
On the other hand, often one has good a priori knowledge about the number of entries a row contains on average. The implicit mode tries to make use of that knowledge, and allows the setup of matrix pattern and numerical values together.
Constructing and filling a BCRSMatrix with the 'implicit' mode is performed in two steps: In a setup phase, matrix entries with numerical values can be inserted into the matrix. Then, a compression algorithm is called which defragments and optimizes the memory layout. After this compression step, the matrix is ready to be used, and no further nonzero entries can be added.
To use this mode, either construct a matrix object via
or default-construct the matrix and then call
The parameter _avg specifies the expected number of (block) entries per matrix row.
When the BCRSMatrix object is first constructed with the 'implicit' build mode, two areas for matrix entry storage are allocated:
1) A large continuous chunk of memory that can hold the expected number of entries. In addition, this chunk contains an extra part of memory called the 'compression buffer', located before the memory for the matrix itself. The size of this buffer will be _avg * _n * compressionBufferSize.
2) An associative container indexed by 
You can then start filling your matrix by calling entry(size_type row, size_type col), which returns the corresponding matrix entry, creating it on the fly if it does not exist yet. The matrix pattern is hence created implicitly by simply accessing nonzero entries during the initial matrix assembly. Note that new entries are not zero-initialized, though, and hence the first operation on each entry has to be an assignment.
If a row contains more non-zero entries than what was specified in the _avg parameter, the surplus entries are stored in the 'overflow area' during the initial setup phase. After all indices are added, call compress() to trigger the compression step that optimizes the matrix and integrates any entries from the overflow area into the standard BCRS storage. This compression step builds up the final memory layout row by row. It will fail with an exception if the compression buffer is not large enough, which would lead to compressed rows overwriting uncompressed ones. More precisely, if 


![\[ M_i = \textrm{avg} + A + \sum_{j<i} (\textrm{avg} - \textrm{nnz}_j)
\]](form_23.png)
for all 

The data of the matrix is now located at the beginning of the allocated area, and covers what used to be the compression buffer. In exchange, there is now unused space at the end of the large allocated piece of memory. This will go unused and cannot be freed during the lifetime of the matrix, but it has no negative impact on run-time performance. No matrix entries may be added after the compression step.
The compress() method returns a value of type Dune::CompressionStatistics, which you can inspect to tune the construction parameters _avg and compressionBufferSize.
Use of copy constructor, assignment operator and matrix vector arithmetic is not supported until the matrix is fully built.
The following sample code constructs a 
Internally the index array now looks like this:
The second row denotes the beginnings of the matrix rows. The eight 'x' on the left are the compression buffer. The overflow area contains the entries (1,5,0.0), (3,8,0.0), (5,8,0.0), (7,8,0.0), and (9,8,0.0). These are entries of rows 1, 3, 5, 7, and 9, which have three entries each, even though only two were anticipated.
Internally the index array now looks like this:
The compression buffer on the left is gone now, and the matrix has a real CRS layout. The 'x' on the right will be unused for the rest of the matrix' lifetime. */ template<class B, class A=std::allocator > class BCRSMatrix { friend struct MatrixDimension<BCRSMatrix>; public: enum BuildStage { /** Matrix is not built at all, no memory has been allocated, build mode and size can still be set.
| size_type Dune::CompressionStatistics< size_type >::overflow_total |
total number of elements written to the overflow area during construction.
| * implement row_type with compressed vector typedef Imp::CompressedBlockVectorWindow<B,size_type> Dune::row_type |
| Dune::rowSizesBuilt =2 |
The row sizes of the matrix are known.
Only used in random mode.
| * The type for the index access and the size typedef A::size_type Dune::size_type |
| * brief The unqualified value type typedef std::remove_const<T>::type Dune::RealRowIterator< T >::ValueType |