sparse_matrix.c File Reference

#include <stdlib.h>
#include <math.h>
#include <grass/gmath.h>
#include <grass/gis.h>

Include dependency graph for sparse_matrix.c:

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Functions
int	G_math_add_spvector (G_math_spvector **Asp, G_math_spvector *spvector, int row)
	Adds a sparse vector to a sparse matrix at position row. More...
G_math_spvector **	G_math_alloc_spmatrix (int rows)
	Allocate memory for a sparse matrix. More...
G_math_spvector *	G_math_alloc_spvector (int cols)
	Allocate memory for a sparse vector. More...
void	G_math_free_spvector (G_math_spvector *spvector)
	Release the memory of the sparse vector. More...
void	G_math_free_spmatrix (G_math_spvector **Asp, int rows)
	Release the memory of the sparse matrix. More...
void	G_math_print_spmatrix (G_math_spvector **Asp, int rows)
	print the sparse matrix Asp to stdout More...
double **	G_math_Asp_to_A (G_math_spvector **Asp, int rows)
	Convert a sparse matrix into a quadratic matrix. More...
double **	G_math_Asp_to_sband_matrix (G_math_spvector **Asp, int rows, int bandwidth)
	Convert a symmetric sparse matrix into a symmetric band matrix. More...
G_math_spvector **	G_math_A_to_Asp (double **A, int rows, double epsilon)
	Convert a quadratic matrix into a sparse matrix. More...
G_math_spvector **	G_math_sband_matrix_to_Asp (double **A, int rows, int bandwidth, double epsilon)
	Convert a symmetric band matrix into a sparse matrix. More...
void	G_math_Ax_sparse (G_math_spvector **Asp, double *x, double *y, int rows)
	Compute the matrix - vector product of sparse matrix **Asp and vector x. More...

Function Documentation

G_math_A_to_Asp()

G_math_spvector** G_math_A_to_Asp	(	double **	A,
		int	rows,
		double	epsilon
	)

Convert a quadratic matrix into a sparse matrix.

This function is multi-threaded with OpenMP. It creates its own parallel OpenMP region.

Parameters

A	(double **)
rows	(int)
epsilon	(double) – non-zero values are greater then epsilon

Returns

(G_math_spvector **)

Definition at line 253 of file sparse_matrix.c.

G_math_add_spvector()

int G_math_add_spvector	(	G_math_spvector **	Asp,
		G_math_spvector *	spvector,
		int	row
	)

Adds a sparse vector to a sparse matrix at position row.

Return 1 for success and -1 for failure

Parameters

Asp	G_math_spvector **
spvector	G_math_spvector *
row	int

Returns

int 1 success, -1 failure

Definition at line 35 of file sparse_matrix.c.

References G_debug(), and NULL.

G_math_alloc_spmatrix()

G_math_spvector** G_math_alloc_spmatrix

(

int

rows

)

Allocate memory for a sparse matrix.

Parameters

rows

int

Returns

G_math_spvector **

Definition at line 58 of file sparse_matrix.c.

References G_calloc, and G_debug().

G_math_alloc_spvector()

G_math_spvector* G_math_alloc_spvector

(

int

cols

)

Allocate memory for a sparse vector.

Parameters

cols

int

Returns

G_math_spvector *

Definition at line 76 of file sparse_matrix.c.

References G_math_spvector::cols, G_calloc, G_debug(), G_math_spvector::index, and G_math_spvector::values.

Referenced by N_assemble_les_2d_param(), and N_assemble_les_3d_param().

G_math_Asp_to_A()

double** G_math_Asp_to_A	(	G_math_spvector **	Asp,
		int	rows
	)

Convert a sparse matrix into a quadratic matrix.

This function is multi-threaded with OpenMP. It creates its own parallel OpenMP region.

Parameters

Asp	(G_math_spvector **)
rows	(int)

Returns

(double **)

Definition at line 179 of file sparse_matrix.c.

G_math_Asp_to_sband_matrix()

double** G_math_Asp_to_sband_matrix	(	G_math_spvector **	Asp,
		int	rows,
		int	bandwidth
	)

Convert a symmetric sparse matrix into a symmetric band matrix.

Symmetric matrix with bandwidth of 3

5 2 1 0
2 5 2 1
1 2 5 2
0 1 2 5

will be converted into the band matrix

5 2 1
5 2 1
5 2 0
5 0 0

Parameters

Asp	(G_math_spvector **)
rows	(int)
bandwidth	(int)

Returns

(double **) the resulting ymmetric band matrix [rows][bandwidth]

Definition at line 221 of file sparse_matrix.c.

G_math_Ax_sparse()

void G_math_Ax_sparse	(	G_math_spvector **	Asp,
		double *	x,
		double *	y,
		int	rows
	)

Compute the matrix - vector product of sparse matrix **Asp and vector x.

This function is multi-threaded with OpenMP and can be called within a parallel OpenMP region.

y = A * x

Parameters

Asp	(G_math_spvector **)
x	(double) *)
y	(double * )
rows	(int)

Returns

(void)

Definition at line 363 of file sparse_matrix.c.

Referenced by N_les_integrate_dirichlet_2d(), and N_les_integrate_dirichlet_3d().

G_math_free_spmatrix()

void G_math_free_spmatrix	(	G_math_spvector **	Asp,
		int	rows
	)

Release the memory of the sparse matrix.

Parameters

Asp	G_math_spvector **
rows	int

Returns

void

Definition at line 121 of file sparse_matrix.c.

References G_free(), G_math_free_spvector(), and NULL.

Referenced by N_free_les().

G_math_free_spvector()

void G_math_free_spvector

(

G_math_spvector *

spvector

)

Release the memory of the sparse vector.

Parameters

spvector

G_math_spvector *

Returns

void

Definition at line 98 of file sparse_matrix.c.

References G_free(), G_math_spvector::index, NULL, and G_math_spvector::values.

Referenced by G_math_free_spmatrix().

G_math_print_spmatrix()

void G_math_print_spmatrix	(	G_math_spvector **	Asp,
		int	rows
	)

print the sparse matrix Asp to stdout

Parameters

Asp	(G_math_spvector **)
rows	(int)

Returns

void

Definition at line 146 of file sparse_matrix.c.

References G_math_spvector::cols.

G_math_sband_matrix_to_Asp()

G_math_spvector** G_math_sband_matrix_to_Asp	(	double **	A,
		int	rows,
		int	bandwidth,
		double	epsilon
	)

Convert a symmetric band matrix into a sparse matrix.

WARNING: This function is experimental, do not use. Only the upper triangle matrix of the band strcuture is copied.

Parameters

A	(double **) the symmetric band matrix
rows	(int)
bandwidth	(int)
epsilon	(double) – non-zero values are greater then epsilon

Returns

(G_math_spvector **)

Definition at line 304 of file sparse_matrix.c.