19 lines
469 B
C
19 lines
469 B
C
#include "cs.h"
|
|
/* solve U'x=b where x and b are dense. x=b on input, solution on output. */
|
|
int cs_utsolve (const cs *U, double *x)
|
|
{
|
|
int p, j, n, *Up, *Ui ;
|
|
double *Ux ;
|
|
if (!CS_CSC (U) || !x) return (0) ; /* check inputs */
|
|
n = U->n ; Up = U->p ; Ui = U->i ; Ux = U->x ;
|
|
for (j = 0 ; j < n ; j++)
|
|
{
|
|
for (p = Up [j] ; p < Up [j+1]-1 ; p++)
|
|
{
|
|
x [j] -= Ux [p] * x [Ui [p]] ;
|
|
}
|
|
x [j] /= Ux [Up [j+1]-1] ;
|
|
}
|
|
return (1) ;
|
|
}
|