Templated sparse vector class. More...

#include <itpp/base/svec.h>

Public Member Functions
	Sparse_Vec ()
	Default constructor.

	Sparse_Vec (int sz, int data_init=200)
	Initiate an empty sparse vector.

	Sparse_Vec (const Sparse_Vec< T > &v)
	Initiate a new sparse vector.

	Sparse_Vec (const Vec< T > &v)
	Initiate a new sparse vector from a dense vector.

	Sparse_Vec (const Vec< T > &v, T epsilon)
	Initiate a new sparse vector from a dense vector. Elements of `v` larger than `epsilon` are copied into the new sparse vector.

	~Sparse_Vec ()
	Destructor.

void	set_size (int sz, int data_init=-1)
	Set the size `sz` of the sparse vector. Default value `data_init=-1` `=>` allocated size for the data is not changed.

int	size () const
	Returns the size of the sparse vector.

int	nnz ()
	Number of non-zero elements in the sparse vector.

double	density ()
	Returns the density of the sparse vector: (number of non-zero elements)/(size of the vector)

void	set_small_element (const T &epsilon)
	Set that all elements smaller than epsilon should be set to zero.

void	remove_small_elements ()

void	resize_data (int new_size)
	Set the maximum number of non-zero elements to `new_size`.

void	compact ()
	Set the maximum number of non-zero elements equal to the actual number of non-zero elements.

void	full (Vec< T > &v) const
	Returns a full, dense vector in `v`.

Vec< T >	full () const
	Returns a full, dense vector.

T	operator() (int i) const
	Returns the element with index `i`.

void	set (int i, T v)
	Set element `i` equal to `v`.

void	set (const ivec &index_vec, const Vec< T > &v)
	Set the elements of the sparse vector with indices `index_vec` to the values in `v`.

void	set_new (int i, T v)
	Set a new element with index `i` equal to `v`.

void	set_new (const ivec &index_vec, const Vec< T > &v)
	Set new elements with indices `index_vec` equal to the values in `v` (no check whether the same index is used several times)

void	add_elem (const int i, const T v)
	Add element `i` with `v`.

void	add (const ivec &index_vec, const Vec< T > &v)
	Add `v` to the elements specified by `index_vec` with `v`.

void	zeros ()
	Set the sparse vector to the all zero vector (removes all non-zero elements)

void	zero_elem (const int i)
	Set the i-th element to zero (i.e. clear that element if it contains a non-zero value)

void	clear ()
	Clear all non-zero elements of the sparse vector.

void	clear_elem (const int i)
	Clear the i-th element (if it contains a non-zero value)

void	get_nz_data (int p, T &data_out)
	Extract the reference to the p-th non-zero data element.

T	get_nz_data (int p)
	Returns the p-th non-zero data element.

int	get_nz_index (int p)
	Returns the vector index of the p-th non-zero element.

void	get_nz (int p, int &idx, T &dat)
	Returns the p-th non-zero value in `dat` and the corresponding vector index in `idx`.

ivec	get_nz_indices ()
	Return the indices of non-zero values.

Sparse_Vec< T >	get_subvector (int i1, int i2) const
	Return sparse subvector from index `i1` to index `i2`.

T	sqr () const
	Returns the sum of all values squared.

void	operator= (const Sparse_Vec< T > &v)
	Assign sparse vector the value and length of the sparse vector `v`.

void	operator= (const Vec< T > &v)
	Assign sparse vector the value and length of the dense vector `v`.

Sparse_Vec< T >	operator- () const
	Returns the sign inverse of all elements in the sparse vector.

bool	operator== (const Sparse_Vec< T > &v)
	Compare two sparse vectors. False if wrong sizes or different values.

void	operator+= (const Sparse_Vec< T > &v)
	Add sparse vector `v` to all non-zero elements of the sparse vector.

void	operator+= (const Vec< T > &v)
	Add vector `v` to all non-zero elements of the sparse vector.

void	operator-= (const Sparse_Vec< T > &v)
	Subtract sparse vector `v` from all non-zero elements of the sparse vector.

void	operator-= (const Vec< T > &v)
	Subtract vector `v` from all non-zero elements of the sparse vector.

void	operator*= (const T &v)
	Multiply the scalar `v` to all non-zero elements of the sparse vector.

void	operator/= (const T &v)
	Divide all non-zero elements of the sparse vector with the scalar `v`.

Friends
Sparse_Vec< T >	operator+ (const Sparse_Vec< T > &v1, const Sparse_Vec< T > &v2)
	Addition v1+v2 where v1 and v2 are sparse vector.

T	operator* (const Sparse_Vec< T > &v1, const Sparse_Vec< T > &v2)
	Scalar product v1*v2 where v1 and v2 are sparse vectors.

T	operator* (const Sparse_Vec< T > &v1, const Vec< T > &v2)
	Scalar product v1*v2 where v1 is a sparse vector and v2 is a dense vector.

T	operator* (const Vec< T > &v1, const Sparse_Vec< T > &v2)
	Scalar product v1*v2 where v1 is a dense vector and v2 is a sparse vector.

Sparse_Vec< T >	elem_mult (const Sparse_Vec< T > &v1, const Sparse_Vec< T > &v2)
	Element wise multiplication of two sparse vectors.

Vec< T >	elem_mult (const Sparse_Vec< T > &v1, const Vec< T > &v2)
	Element wise multiplication of a sparse vector and a dense vector.

Sparse_Vec< T >	elem_mult_s (const Sparse_Vec< T > &v1, const Vec< T > &v2)
	Element wise multiplication of a sparse vector and a dense vector returning a sparse vector.

Vec< T >	elem_mult (const Vec< T > &v1, const Sparse_Vec< T > &v2)
	Element wise multiplication of a a dense vector and a sparse vector.

Sparse_Vec< T >	elem_mult_s (const Vec< T > &v1, const Sparse_Vec< T > &v2)
	Element wise multiplication of a a dense vector and a sparse vector returning a sparse vector.

Detailed Description

template<class T>
class itpp::Sparse_Vec< T >

Templated sparse vector class.

Author: Tony Ottosson and Tobias Ringstrom

A sparse vector is a vector where most elements are zero. The maximum number of none-zero elements is a parameter to the constructor. The elements are stored in random order, i.e. they are not sorted.

Definition at line 107 of file svec.h.

Constructor & Destructor Documentation

template<class T >

Sparse_Vec< T >::Sparse_Vec	(	int	sz,
		int	data_init = `200`
	)

Initiate an empty sparse vector.

Parameters

sz	Size of the sparse vector (i.e. maximum index is (`sz` - 1))
data_init	Maximum number of non-zero elements in the sparse vector (default value 200)

Definition at line 394 of file svec.h.

template<class T>

Sparse_Vec< T >::Sparse_Vec ( const Sparse_Vec< T > & v )

Initiate a new sparse vector.

Parameters

v	The elements of `v` are copied into the new sparse vector

Definition at line 404 of file svec.h.

References itpp::eps.

template<class T>

Sparse_Vec< T >::Sparse_Vec ( const Vec< T > & v )

Initiate a new sparse vector from a dense vector.

Parameters

v	The elements of `v` are copied into the new sparse vector

Definition at line 421 of file svec.h.

References itpp::min(), and itpp::Vec< Num_T >::size().

template<class T>

Sparse_Vec< T >::Sparse_Vec	(	const Vec< T > &	v,
		T	epsilon
	)

Initiate a new sparse vector from a dense vector. Elements of v larger than epsilon are copied into the new sparse vector.

Note: If the type T is complex<double>, then the elements of v larger than abs(epsilon) are copied into the new sparse vector.

Definition at line 442 of file svec.h.

References itpp::abs(), itpp::eps, itpp::min(), and itpp::Vec< Num_T >::size().

Member Function Documentation

template<class T >

void Sparse_Vec< T >::set_size	(	int	sz,
		int	data_init = `-1`
	)

Set the size sz of the sparse vector. Default value data_init=-1 => allocated size for the data is not changed.

Parameters

sz	Size of the sparse vector (i.e. maximum index is (`sz` - 1))
data_init	Maximum number of non-zero elements in the sparse vector (default value -1 `=>` allocated size for the data is not changed)

Definition at line 470 of file svec.h.

template<class T >

void Sparse_Vec< T >::remove_small_elements ( )

Removes all elements that are smaller than epsilon from the non-zero elements.

Note: The small element epsilon can be set by the member function set_small_element. If no small value is set, the default value is always epsilon=0.

Definition at line 499 of file svec.h.

References itpp::abs(), and itpp::eps.

Referenced by itpp::Sparse_Vec< bin >::get_nz(), itpp::Sparse_Vec< bin >::get_nz_data(), itpp::Sparse_Vec< bin >::get_nz_index(), and itpp::Sparse_Vec< bin >::nnz().

template<class T >

void Sparse_Vec< T >::resize_data ( int new_size )

Set the maximum number of non-zero elements to new_size.

Parameters

new_size The new maximum number of non-zero elements.

Definition at line 524 of file svec.h.

References it_assert.

Referenced by itpp::elem_mult(), itpp::Sparse_Vec< T >::get_subvector(), and itpp::operator+().

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