int glp_factorize(glp_prob *lp)
{ int m = lp->m;
int n = lp->n;
GLPROW **row = lp->row;
GLPCOL **col = lp->col;
int *head = lp->head;
int j, k, stat, ret;
/* invalidate the basis factorization */
lp->valid = 0;
/* build the basis header */
j = 0;
for (k = 1; k <= m+n; k++)
{ if (k <= m)
{ stat = row[k]->stat;
row[k]->bind = 0;
}
else
{ stat = col[k-m]->stat;
col[k-m]->bind = 0;
}
if (stat == GLP_BS)
{ j++;
if (j > m)
{ /* too many basic variables */
ret = GLP_EBADB;
goto fini;
}
head[j] = k;
if (k <= m)
row[k]->bind = j;
else
col[k-m]->bind = j;
}
}
if (j < m)
{ /* too few basic variables */
ret = GLP_EBADB;
goto fini;
}
/* try to factorize the basis matrix */
if (m > 0)
{ _glp_access_bfd(lp);
xassert(lp->bfd != NULL);
switch (bfd_factorize(lp->bfd, m, lp->head, b_col, lp))
{ case 0:
/* ok */
break;
case BFD_ESING:
/* singular matrix */
ret = GLP_ESING;
goto fini;
case BFD_ECOND:
/* ill-conditioned matrix */
ret = GLP_ECOND;
goto fini;
default:
xassert(lp != lp);
}
lp->valid = 1;
}
/* factorization successful */
ret = 0;
fini: /* bring the return code to the calling program */
return ret;
}
int spx_factorize(SPXLP *lp)
{ int ret;
ret = bfd_factorize(lp->bfd, lp->m, jth_col, lp);
lp->valid = (ret == 0);
return ret;
}
