c++boost.gifSparse Vector

Sparse Vector

Description

The templated class sparse_vector<T, A> is the base container adaptor for sparse vectors. For a n-dimensional sparse vector and 0 <= i < n every non-zero element vi is mapped to the i-th element of the container.

Example

int main () {
    using namespace boost::numeric::ublas;
    sparse_vector<double> v (3, 3);
    for (int i = 0; i < v.size (); ++ i) 
        v (i) = i;
    std::cout << v << std::endl;
}

Definition

Defined in the header vector_sparse.hpp.

Template parameters

Parameter Description Default
T The type of object stored in the sparse vector.  
F Functor describing the storage organization. forward
A The type of the adapted array. map_array<std::size_t, T>

Model of

Vector.

Type requirements

None, except for those imposed by the requirements of Vector.

Public base classes

vector_expression<sparse_vector<T, A> >

Members

Member Description
sparse_vector () Allocates a sparse_vector that holds zero elements.
sparse_vector (size_type size, size_type non_zeros) Allocates a sparse_vector that holds at most size elements.
sparse_vector (const sparse_vector &v) The copy constructor.
template<class AE>
sparse_vector (size_type non_zeros, const vector_expression<AE> &ae)
The extended copy constructor.
void resize (size_type size, size_type non_zeros) Reallocates a sparse_vector to hold at most size elements. The content of the sparse_vector is preserved.
size_type size () const Returns the size of the sparse_vector.
const_reference operator () (size_type i) const Returns the value of the i-th element.
reference operator () (size_type i) Returns a reference of the i-th element.
const_reference operator [] (size_type i) const Returns the value of the i-th element.
reference operator [] (size_type i) Returns a reference of the i-th element.
sparse_vector &operator = (const sparse_vector &v) The assignment operator.
sparse_vector &assign_temporary (sparse_vector &v) Assigns a temporary. May change the sparse vector v.
template<class AE>
sparse_vector &operator = (const vector_expression<AE> &ae)
The extended assignment operator.
template<class AE>
sparse_vector &assign (const vector_expression<AE> &ae)
Assigns a vector expression to the sparse vector. Left and right hand side of the assignment should be independent.
template<class AE>
sparse_vector &operator += (const vector_expression<AE> &ae)
A computed assignment operator. Adds the vector expression to the sparse vector.
template<class AE>
sparse_vector &plus_assign (const vector_expression<AE> &ae)
Adds a vector expression to the sparse vector. Left and right hand side of the assignment should be independent.
template<class AE>
sparse_vector &operator -= (const vector_expression<AE> &ae)
A computed assignment operator. Subtracts the vector expression from the sparse vector.
template<class AE>
sparse_vector &minus_assign (const vector_expression<AE> &ae)
Subtracts a vector expression from the sparse vector. Left and right hand side of the assignment should be independent.
template<class AT>
sparse_vector &operator *= (const AT &at)
A computed assignment operator. Multiplies the sparse vector with a scalar.
template<class AT>
sparse_vector &operator /= (const AT &at)
A computed assignment operator. Divides the sparse vector through a scalar.
void swap (sparse_vector &v) Swaps the contents of the sparse vectors.
void insert (size_type i, const_reference t) Inserts the value t at the i-th element.
void erase (size_type i) Erases the value at the i-th element.
void clear () Clears the sparse vector.
const_iterator begin () const Returns a const_iterator pointing to the beginning of the sparse_vector.
const_iterator end () const Returns a const_iterator pointing to the end of the sparse_vector.
iterator begin () Returns a iterator pointing to the beginning of the sparse_vector.
iterator end () Returns a iterator pointing to the end of the sparse_vector.
const_reverse_iterator rbegin () const Returns a const_reverse_iterator pointing to the beginning of the reversed sparse_vector.
const_reverse_iterator rend () const Returns a const_reverse_iterator pointing to the end of the reversed sparse_vector.
reverse_iterator rbegin () Returns a reverse_iterator pointing to the beginning of the reversed sparse_vector.
reverse_iterator rend () Returns a reverse_iterator pointing to the end of the reversed sparse_vector.

Interface

    // Array based sparse vector class 
    template<class T, class A>
    class sparse_vector: 
        public vector_expression<sparse_vector<T, A> > {
    public:      
        typedef std::size_t size_type;
        typedef std::ptrdiff_t difference_type;
        typedef T value_type;
        typedef const T &const_reference;
        typedef T &reference;
        typedef const T *const_pointer;
        typedef T *pointer;
        typedef F functor_type;
        typedef A array_type;
        typedef const A const_array_type;
        typedef const sparse_vector<T, A> const_self_type;
        typedef sparse_vector<T, A> self_type;
        typedef const vector_const_reference<const_self_type> const_closure_type;
        typedef vector_reference<self_type> closure_type;
        typedef typename A::const_iterator const_iterator_type;
        typedef typename A::iterator iterator_type;
        typedef sparse_tag storage_category;

        // Construction and destruction
        sparse_vector (); 
        sparse_vector (size_type size, size_type non_zeros = 0);
        sparse_vector (const sparse_vector &v);
        template<class AE>
        sparse_vector (const vector_expression<AE> &ae, size_type non_zeros = 0);

        // Accessors
        size_type size () const;
        size_type non_zeros () const;
        const_array_type &data () const;
        array_type &data ();

        // Resizing
        void resize (size_type size, size_type non_zeros = 0);

        // Element access
        const_reference operator () (size_type i) const;
        reference operator () (size_type i);

        const_reference operator [] (size_type i) const;
        reference operator [] (size_type i);

        // Assignment
        sparse_vector &operator = (const sparse_vector &v);
        sparse_vector &assign_temporary (sparse_vector &v);
        template<class AE>
        sparse_vector &operator = (const vector_expression<AE> &ae);
        template<class AE>
        sparse_vector &reset (const vector_expression<AE> &ae);
        template<class AE>
        sparse_vector &assign (const vector_expression<AE> &ae);
        template<class AE>
        sparse_vector &operator += (const vector_expression<AE> &ae);
        template<class AE>
        sparse_vector &plus_assign (const vector_expression<AE> &ae);
        template<class AE>
        sparse_vector &operator -= (const vector_expression<AE> &ae);
        template<class AE>
        sparse_vector &minus_assign (const vector_expression<AE> &ae);
        template<class AT>
        sparse_vector &operator *= (const AT &at);
        template<class AT>
        sparse_vector &operator /= (const AT &at);

        // Swapping
        void swap (sparse_vector &v);
        friend void swap (sparse_vector &v1, sparse_vector &v2);

        // Element insertion and erasure
        void insert (size_type i, const_reference t);
        void erase (size_type i);
        void clear ();

        class const_iterator;
        class iterator;

        // Element lookup
        const_iterator find (size_type i) const;
        iterator find (size_type i);
        const_iterator find_first (size_type i) const;
        iterator find_first (size_type i);
        const_iterator find_last (size_type i) const;
        iterator find_last (size_type i);

        // Iterators simply are pointers.

        class const_iterator:
            public container_const_reference<sparse_vector>,
            public bidirectional_iterator_base<const_iterator, value_type> {
        public:
            typedef sparse_bidirectional_iterator_tag iterator_category;
            typedef typename sparse_vector::difference_type difference_type;
            typedef typename sparse_vector::value_type value_type;
            typedef typename sparse_vector::const_reference reference;
            typedef typename sparse_vector::const_pointer pointer;

            // Construction and destruction
            const_iterator ();
            const_iterator (const sparse_vector &v, const const_iterator_type &it);
            const_iterator (const iterator &it);

            // Arithmetic
            const_iterator &operator ++ ();
            const_iterator &operator -- ();

            // Dereference
            reference operator * () const;

            // Index
            size_type index () const;

            // Assignment
            const_iterator &operator = (const const_iterator &it);

            // Comparison
            bool operator == (const const_iterator &it) const;
        };

        const_iterator begin () const;
        const_iterator end () const;

        class iterator:
            public container_reference<sparse_vector>,
            public bidirectional_iterator_base<iterator, value_type> {
        public:
            typedef sparse_bidirectional_iterator_tag iterator_category;
            typedef typename sparse_vector::difference_type difference_type;
            typedef typename sparse_vector::value_type value_type;
            typedef typename sparse_vector::reference reference;
            typedef typename sparse_vector::pointer pointer;

            // Construction and destruction
            iterator ();
            iterator (sparse_vector &v, const iterator_type &it);

            // Arithmetic
            iterator &operator ++ ();
            iterator &operator -- ();

            // Dereference
            reference operator * () const;

            // Index
            size_type index () const;

            // Assignment
            iterator &operator = (const iterator &it);

            // Comparison
            bool operator == (const iterator &it) const;
        };

        iterator begin ();
        iterator end ();

        // Reverse iterator

        typedef reverse_iterator_base<const_iterator> const_reverse_iterator;

        const_reverse_iterator rbegin () const;
        const_reverse_iterator rend () const;

        typedef reverse_iterator_base<iterator> reverse_iterator;

        reverse_iterator rbegin ();
        reverse_iterator rend ();
    };

Copyright (©) 2000-2002 Joerg Walter, Mathias Koch
Permission to copy, use, modify, sell and distribute this document is granted provided this copyright notice appears in all copies. This document is provided ``as is'' without express or implied warranty, and with no claim as to its suitability for any purpose.

Last revised: 8/3/2002