symmetric_band_matrix.c File Reference

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

Include dependency graph for symmetric_band_matrix.c:

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Functions
double **	G_math_matrix_to_sband_matrix (double **A, int rows, int bandwidth)
	Convert a symmetrix matrix into a symmetric band matrix. More...
double **	G_math_sband_matrix_to_matrix (double **A, int rows, int bandwidth)
	Convert a symmetric band matrix into a symmetric matrix. More...
void	G_math_Ax_sband (double **A, double *x, double *y, int rows, int bandwidth)
	Compute the matrix - vector product of symmetric band matrix A and vector x. More...

Function Documentation

G_math_Ax_sband()

void G_math_Ax_sband	(	double **	A,
		double *	x,
		double *	y,
		int	rows,
		int	bandwidth
	)

Compute the matrix - vector product of symmetric band matrix A and vector x.

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

y = A * x

Parameters

A	(double **)
x	(double) *)
y	(double * )
rows	(int)
bandwidth	(int)

Returns

(void)

Definition at line 123 of file symmetric_band_matrix.c.

G_math_matrix_to_sband_matrix()

double** G_math_matrix_to_sband_matrix	(	double **	A,
		int	rows,
		int	bandwidth
	)

Convert a symmetrix 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 symmetric band matrix

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

Parameters

A	(double**) the symmetric matrix
rows	(int)
bandwidth	(int)

Returns

B (double**) new created symmetric band matrix

Definition at line 34 of file symmetric_band_matrix.c.

G_math_sband_matrix_to_matrix()

double** G_math_sband_matrix_to_matrix	(	double **	A,
		int	rows,
		int	bandwidth
	)

Convert a symmetric band matrix into a symmetric matrix.

Such a symmetric band matrix with banwidth 3

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

Will be converted into this symmetric matrix

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

Parameters

A	(double**) the symmetric band matrix
rows	(int)
bandwidth	(int)

Returns

B (double**) new created symmetric matrix

Definition at line 80 of file symmetric_band_matrix.c.