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itpp::Sparse_Vec< T > Class Template Reference

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.
 
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.
 
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.
 
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.
 
operator* (const Sparse_Vec< T > &v1, const Sparse_Vec< T > &v2)
 Scalar product v1*v2 where v1 and v2 are sparse vectors.
 
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.
 
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
szSize of the sparse vector (i.e. maximum index is (sz - 1))
data_initMaximum 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
vThe 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
vThe 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,
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
szSize of the sparse vector (i.e. maximum index is (sz - 1))
data_initMaximum 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_sizeThe 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:
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