GRASS GIS 7 Programmer's Manual  7.5.svn(2018)-r72721
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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:

Go to the source code of this file.

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_spvectorG_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_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.

References count, G_math_add_spvector(), G_math_alloc_spmatrix(), G_math_alloc_spvector(), G_math_spvector::index, NULL, and G_math_spvector::values.

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
AspG_math_spvector **
spvectorG_math_spvector *
rowint
Returns
int 1 success, -1 failure

Definition at line 35 of file sparse_matrix.c.

References G_debug(), and NULL.

Referenced by G_math_A_to_Asp(), G_math_sband_matrix_to_Asp(), N_assemble_les_2d_param(), and N_assemble_les_3d_param().

G_math_spvector** G_math_alloc_spmatrix ( int  rows)

Allocate memory for a sparse matrix.

Parameters
rowsint
Returns
G_math_spvector **

Definition at line 58 of file sparse_matrix.c.

References G_debug().

Referenced by G_math_A_to_Asp(), G_math_sband_matrix_to_Asp(), and N_alloc_les_param().

G_math_spvector* G_math_alloc_spvector ( int  cols)

Allocate memory for a sparse vector.

Parameters
colsint
Returns
G_math_spvector *

Definition at line 76 of file sparse_matrix.c.

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

Referenced by G_math_A_to_Asp(), G_math_sband_matrix_to_Asp(), N_assemble_les_2d_param(), and N_assemble_les_3d_param().

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.

References G_math_spvector::cols, G_alloc_matrix(), G_math_spvector::index, NULL, and G_math_spvector::values.

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.

References G_math_spvector::cols, G_alloc_matrix(), G_math_spvector::index, NULL, and G_math_spvector::values.

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.

References G_math_spvector::cols, G_math_spvector::index, and G_math_spvector::values.

Referenced by N_les_integrate_dirichlet_2d(), and N_les_integrate_dirichlet_3d().

void G_math_free_spmatrix ( G_math_spvector **  Asp,
int  rows 
)

Release the memory of the sparse matrix.

Parameters
AspG_math_spvector **
rowsint
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().

void G_math_free_spvector ( G_math_spvector spvector)

Release the memory of the sparse vector.

Parameters
spvectorG_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().

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_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.

References count, G_math_add_spvector(), G_math_alloc_spmatrix(), G_math_alloc_spvector(), G_math_spvector::index, NULL, and G_math_spvector::values.