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//
// Copyright (c) 2009
// Gunter Winkler
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
//
#ifndef _BOOST_UBLAS_SPARSE_VIEW_
#define _BOOST_UBLAS_SPARSE_VIEW_
#include <boost/numeric/ublas/matrix_expression.hpp>
#include <boost/numeric/ublas/detail/matrix_assign.hpp>
#if BOOST_UBLAS_TYPE_CHECK
#include <boost/numeric/ublas/matrix.hpp>
#endif
#include <boost/next_prior.hpp>
#include <boost/type_traits/remove_cv.hpp>
namespace boost { namespace numeric { namespace ublas {
// view a chunk of memory as ublas array
template < class T >
class c_array_view
: public storage_array< c_array_view<T> > {
private:
typedef c_array_view<T> self_type;
typedef T * pointer;
public:
// TODO: think about a const pointer
typedef const pointer array_type;
typedef std::size_t size_type;
typedef std::ptrdiff_t difference_type;
typedef T value_type;
typedef const T &const_reference;
typedef const T *const_pointer;
typedef const_pointer const_iterator;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
//
// typedefs required by vector concept
//
typedef dense_tag storage_category;
typedef const vector_reference<const self_type> const_closure_type;
c_array_view(size_type size, array_type data) :
size_(size), data_(data)
{}
~c_array_view()
{}
//
// immutable methods of container concept
//
BOOST_UBLAS_INLINE
size_type size () const {
return size_;
}
BOOST_UBLAS_INLINE
const_reference operator [] (size_type i) const {
BOOST_UBLAS_CHECK (i < size_, bad_index ());
return data_ [i];
}
BOOST_UBLAS_INLINE
const_iterator begin () const {
return data_;
}
BOOST_UBLAS_INLINE
const_iterator end () const {
return data_ + size_;
}
BOOST_UBLAS_INLINE
const_reverse_iterator rbegin () const {
return const_reverse_iterator (end ());
}
BOOST_UBLAS_INLINE
const_reverse_iterator rend () const {
return const_reverse_iterator (begin ());
}
private:
size_type size_;
array_type data_;
};
/** \brief Present existing arrays as compressed array based
* sparse matrix.
* This class provides CRS / CCS storage layout.
*
* see also http://www.netlib.org/utk/papers/templates/node90.html
*
* \param L layout type, either row_major or column_major
* \param IB index base, use 0 for C indexing and 1 for
* FORTRAN indexing of the internal index arrays. This
* does not affect the operator()(int,int) where the first
* row/column has always index 0.
* \param IA index array type, e.g., int[]
* \param TA value array type, e.g., double[]
*/
template<class L, std::size_t IB, class IA, class JA, class TA>
class compressed_matrix_view:
public matrix_expression<compressed_matrix_view<L, IB, IA, JA, TA> > {
public:
typedef typename vector_view_traits<TA>::value_type value_type;
private:
typedef value_type &true_reference;
typedef value_type *pointer;
typedef const value_type *const_pointer;
typedef L layout_type;
typedef compressed_matrix_view<L, IB, IA, JA, TA> self_type;
public:
#ifdef BOOST_UBLAS_ENABLE_PROXY_SHORTCUTS
using matrix_expression<self_type>::operator ();
#endif
// ISSUE require type consistency check
// is_convertable (IA::size_type, TA::size_type)
typedef typename boost::remove_cv<typename vector_view_traits<JA>::value_type>::type index_type;
// for compatibility, should be removed some day ...
typedef index_type size_type;
// size_type for the data arrays.
typedef typename vector_view_traits<JA>::size_type array_size_type;
typedef typename vector_view_traits<JA>::difference_type difference_type;
typedef const value_type & const_reference;
// do NOT define reference type, because class is read only
// typedef value_type & reference;
typedef IA rowptr_array_type;
typedef JA index_array_type;
typedef TA value_array_type;
typedef const matrix_reference<const self_type> const_closure_type;
typedef matrix_reference<self_type> closure_type;
// FIXME: define a corresponding temporary type
// typedef compressed_vector<T, IB, IA, TA> vector_temporary_type;
// FIXME: define a corresponding temporary type
// typedef self_type matrix_temporary_type;
typedef sparse_tag storage_category;
typedef typename L::orientation_category orientation_category;
//
// private types for internal use
//
private:
typedef typename vector_view_traits<index_array_type>::const_iterator const_subiterator_type;
//
// Construction and destruction
//
private:
/// private default constructor because data must be filled by caller
BOOST_UBLAS_INLINE
compressed_matrix_view () { }
public:
BOOST_UBLAS_INLINE
compressed_matrix_view (index_type n_rows, index_type n_cols, array_size_type nnz
, const rowptr_array_type & iptr
, const index_array_type & jptr
, const value_array_type & values):
matrix_expression<self_type> (),
size1_ (n_rows), size2_ (n_cols),
nnz_ (nnz),
index1_data_ (iptr),
index2_data_ (jptr),
value_data_ (values) {
storage_invariants ();
}
BOOST_UBLAS_INLINE
compressed_matrix_view(const compressed_matrix_view& o) :
size1_(size1_), size2_(size2_),
nnz_(nnz_),
index1_data_(index1_data_),
index2_data_(index2_data_),
value_data_(value_data_)
{}
//
// implement immutable iterator types
//
class const_iterator1 {};
class const_iterator2 {};
typedef reverse_iterator_base1<const_iterator1> const_reverse_iterator1;
typedef reverse_iterator_base2<const_iterator2> const_reverse_iterator2;
//
// implement all read only methods for the matrix expression concept
//
//! return the number of rows
index_type size1() const {
return size1_;
}
//! return the number of columns
index_type size2() const {
return size2_;
}
//! return value at position (i,j)
value_type operator()(index_type i, index_type j) const {
const_pointer p = find_element(i,j);
if (!p) {
return zero_;
} else {
return *p;
}
}
private:
//
// private helper functions
//
const_pointer find_element (index_type i, index_type j) const {
index_type element1 (layout_type::index_M (i, j));
index_type element2 (layout_type::index_m (i, j));
const array_size_type itv = zero_based( index1_data_[element1] );
const array_size_type itv_next = zero_based( index1_data_[element1+1] );
const_subiterator_type it_start = boost::next(vector_view_traits<index_array_type>::begin(index2_data_),itv);
const_subiterator_type it_end = boost::next(vector_view_traits<index_array_type>::begin(index2_data_),itv_next);
const_subiterator_type it = find_index_in_row(it_start, it_end, element2) ;
if (it == it_end || *it != k_based (element2))
return 0;
return &value_data_ [it - vector_view_traits<index_array_type>::begin(index2_data_)];
}
const_subiterator_type find_index_in_row(const_subiterator_type it_start
, const_subiterator_type it_end
, index_type index) const {
return std::lower_bound( it_start
, it_end
, k_based (index) );
}
private:
void storage_invariants () const {
BOOST_UBLAS_CHECK (index1_data_ [layout_type::size_M (size1_, size2_)] == k_based (nnz_), external_logic ());
}
index_type size1_;
index_type size2_;
array_size_type nnz_;
const rowptr_array_type & index1_data_;
const index_array_type & index2_data_;
const value_array_type & value_data_;
static const value_type zero_;
BOOST_UBLAS_INLINE
static index_type zero_based (index_type k_based_index) {
return k_based_index - IB;
}
BOOST_UBLAS_INLINE
static index_type k_based (index_type zero_based_index) {
return zero_based_index + IB;
}
friend class iterator1;
friend class iterator2;
friend class const_iterator1;
friend class const_iterator2;
};
template<class L, std::size_t IB, class IA, class JA, class TA >
const typename compressed_matrix_view<L,IB,IA,JA,TA>::value_type
compressed_matrix_view<L,IB,IA,JA,TA>::zero_ = value_type/*zero*/();
template<class L, std::size_t IB, class IA, class JA, class TA >
compressed_matrix_view<L,IB,IA,JA,TA>
make_compressed_matrix_view(typename vector_view_traits<JA>::value_type n_rows
, typename vector_view_traits<JA>::value_type n_cols
, typename vector_view_traits<JA>::size_type nnz
, const IA & ia
, const JA & ja
, const TA & ta) {
return compressed_matrix_view<L,IB,IA,JA,TA>(n_rows, n_cols, nnz, ia, ja, ta);
}
}}}
#endif