hogman_minimal: cs_utsolve.c Source File

00001 #include "cs.h"
00002 /* solve U'x=b where x and b are dense.  x=b on input, solution on output. */
00003 int cs_utsolve (const cs *U, double *x)
00004 {
00005     int p, j, n, *Up, *Ui ;
00006     double *Ux ;
00007     if (!CS_CSC (U) || !x) return (0) ;                     /* check inputs */
00008     n = U->n ; Up = U->p ; Ui = U->i ; Ux = U->x ;
00009     for (j = 0 ; j < n ; j++)
00010     {
00011         for (p = Up [j] ; p < Up [j+1]-1 ; p++)
00012         {
00013             x [j] -= Ux [p] * x [Ui [p]] ;
00014         }
00015         x [j] /= Ux [Up [j+1]-1] ;
00016     }
00017     return (1) ;
00018 }