vnl_crs_index Class Reference

Represents the configuration of a sparse matrix but not the data. More...

#include <vnl_crs_index.h>

Public Types
typedef std::pair< int, int >	idx_pair
typedef std::vector< idx_pair >	sparse_vector

Public Member Functions
	vnl_crs_index ()
	Constructor - default. More...
	vnl_crs_index (const std::vector< std::vector< bool > > &mask)
	Constructor - from a binary mask. More...
	~vnl_crs_index ()=default
	Destructor. More...
int	num_rows () const
	number of rows in the sparse matrix. More...
int	num_cols () const
	number of columns in the sparse matrix. More...
int	num_non_zero () const
	number of non-zero elements. More...
sparse_vector	sparse_row (int i) const
	returns row i as a vector of index-column pairs. More...
sparse_vector	sparse_col (int j) const
	returns column j as a vector of index-row pairs. More...
int	operator() (int i, int j) const
	return the index at location (i,j). More...

Private Attributes
unsigned int	num_cols_
	The number of columns in the matrix. More...
std::vector< int >	col_idx_
	The column for each non-zero element. More...
std::vector< int >	row_ptr_
	The index of the first non-zero element in each row. More...

Detailed Description

Represents the configuration of a sparse matrix but not the data.

This is essentially a sparse matrix of indices into a data vector Compressed row storage is used for representation This class is useful when working with several sparse matrices that share a common sparse structure.

Definition at line 26 of file vnl_crs_index.h.

Member Typedef Documentation

idx_pair

typedef std::pair<int,int> vnl_crs_index::idx_pair

Definition at line 29 of file vnl_crs_index.h.

sparse_vector

typedef std::vector<idx_pair> vnl_crs_index::sparse_vector

Definition at line 30 of file vnl_crs_index.h.

Constructor & Destructor Documentation

vnl_crs_index() [1/2]

vnl_crs_index::vnl_crs_index ( )

inline

Constructor - default.

Definition at line 33 of file vnl_crs_index.h.

vnl_crs_index() [2/2]

vnl_crs_index::vnl_crs_index

(

const std::vector< std::vector< bool > > &

mask

)

Constructor - from a binary mask.

Definition at line 10 of file vnl_crs_index.cxx.

~vnl_crs_index()

vnl_crs_index::~vnl_crs_index ( )

default

Destructor.

Member Function Documentation

num_cols()

int vnl_crs_index::num_cols ( ) const

inline

number of columns in the sparse matrix.

Definition at line 45 of file vnl_crs_index.h.

num_non_zero()

int vnl_crs_index::num_non_zero ( ) const

inline

number of non-zero elements.

Definition at line 48 of file vnl_crs_index.h.

num_rows()

int vnl_crs_index::num_rows ( ) const

inline

number of rows in the sparse matrix.

Definition at line 42 of file vnl_crs_index.h.

operator()()

int vnl_crs_index::operator()	(	int	i,
		int	j
	)		const

return the index at location (i,j).

returns -1 if the entry is 0

Definition at line 31 of file vnl_crs_index.cxx.

sparse_col()

vnl_crs_index::sparse_vector vnl_crs_index::sparse_col

(

int

j

)

const

returns column j as a vector of index-row pairs.

Note

because of CRS this method is a bit less efficient than sparse_row

Definition at line 69 of file vnl_crs_index.cxx.

sparse_row()

vnl_crs_index::sparse_vector vnl_crs_index::sparse_row

(

int

i

)

const

returns row i as a vector of index-column pairs.

Definition at line 56 of file vnl_crs_index.cxx.

Member Data Documentation

col_idx_

std::vector<int> vnl_crs_index::col_idx_

private

The column for each non-zero element.

Definition at line 65 of file vnl_crs_index.h.

num_cols_

unsigned int vnl_crs_index::num_cols_

private

The number of columns in the matrix.

Definition at line 63 of file vnl_crs_index.h.

row_ptr_

std::vector<int> vnl_crs_index::row_ptr_

private

The index of the first non-zero element in each row.

Definition at line 67 of file vnl_crs_index.h.

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

• core/vnl/vnl_crs_index.h
• core/vnl/vnl_crs_index.cxx