1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
#include "cs.h"
/* C = A*B */
cs *cs_multiply (const cs *A, const cs *B)
{
int p, j, nz = 0, anz, *Cp, *Ci, *Bp, m, n, bnz, *w, values, *Bi ;
double *x, *Bx, *Cx ;
cs *C ;
if (!CS_CSC (A) || !CS_CSC (B)) return (NULL) ; /* check inputs */
if (A->n != B->m) return (NULL) ;
m = A->m ; anz = A->p [A->n] ;
n = B->n ; Bp = B->p ; Bi = B->i ; Bx = B->x ; bnz = Bp [n] ;
w = cs_calloc (m, sizeof (int)) ; /* get workspace */
values = (A->x != NULL) && (Bx != NULL) ;
x = values ? cs_malloc (m, sizeof (double)) : NULL ; /* get workspace */
C = cs_spalloc (m, n, anz + bnz, values, 0) ; /* allocate result */
if (!C || !w || (values && !x)) return (cs_done (C, w, x, 0)) ;
Cp = C->p ;
for (j = 0 ; j < n ; j++)
{
if (nz + m > C->nzmax && !cs_sprealloc (C, 2*(C->nzmax)+m))
{
return (cs_done (C, w, x, 0)) ; /* out of memory */
}
Ci = C->i ; Cx = C->x ; /* C->i and C->x may be reallocated */
Cp [j] = nz ; /* column j of C starts here */
for (p = Bp [j] ; p < Bp [j+1] ; p++)
{
nz = cs_scatter (A, Bi [p], Bx ? Bx [p] : 1, w, x, j+1, C, nz) ;
}
if (values) for (p = Cp [j] ; p < nz ; p++) Cx [p] = x [Ci [p]] ;
}
Cp [n] = nz ; /* finalize the last column of C */
cs_sprealloc (C, 0) ; /* remove extra space from C */
return (cs_done (C, w, x, 1)) ; /* success; free workspace, return C */
}
|
