File: cs_utsolve.c

package info (click to toggle)
naev 0.8.2-1
  • links: PTS, VCS
  • area: main
  • in suites: bookworm, forky, sid, trixie
  • size: 386,084 kB
  • sloc: ansic: 93,149; xml: 87,292; python: 2,347; sh: 904; makefile: 654; lisp: 162; awk: 4
file content (18 lines) | stat: -rw-r--r-- 469 bytes parent folder | download | duplicates (6) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
 
#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) ;
}