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#include "cs_mex.h"
/* find nonzero pattern of x=L\sparse(b). L must be sparse, real, and lower
* triangular. b must be a real sparse vector. */
void mexFunction
(
int nargout,
mxArray *pargout [ ],
int nargin,
const mxArray *pargin [ ]
)
{
cs Lmatrix, Bmatrix, *L, *B ;
double *x ;
int k, i, j, top, *xi, *perm ;
if (nargout > 1 || nargin != 2)
{
mexErrMsgTxt ("Usage: x = cs_reach(L,b)") ;
}
/* get inputs */
L = cs_mex_get_sparse (&Lmatrix, 1, 1, pargin [0]) ;
B = cs_mex_get_sparse (&Bmatrix, 0, 1, pargin [1]) ;
cs_mex_check (0, L->n, 1, 0, 1, 1, pargin [1]) ;
perm = cs_malloc (L->n, sizeof (int)) ;
for (k = 0 ; k < L->n ; k++) perm [k] = k ;
xi = cs_calloc (3*L->n, sizeof (int)) ;
top = cs_reach (L, B, 0, xi, perm) ;
pargout [0] = mxCreateDoubleMatrix (L->n - top, 1, mxREAL) ;
x = mxGetPr (pargout [0]) ;
for (j = 0, i = top ; i < L->n ; i++, j++) x [j] = xi [i] ;
cs_free (xi) ;
cs_free (perm) ;
}
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