/*! @file ilu_zsnode_dfs.c

 * \brief Determines the union of row structures of columns within the relaxed node

 *

 * 

 * -- SuperLU routine (version 4.0) --

 * Lawrence Berkeley National Laboratory

 * June 30, 2009

 * 

 */

#include "slu_zdefs.h"

/*! \brief

 *

 * 

 * Purpose

 * =======

 *    ilu_zsnode_dfs() - Determine the union of the row structures of those

 *    columns within the relaxed snode.

 *    Note: The relaxed snodes are leaves of the supernodal etree, therefore,

 *    the portion outside the rectangular supernode must be zero.

 *

 * Return value

 * ============

 *     0   success;

 *    >0   number of bytes allocated when run out of memory.

 * 

 */

int

ilu_zsnode_dfs(

	   const int  jcol,	    /* in - start of the supernode */

	   const int  kcol,	    /* in - end of the supernode */

	   const int  *asub,	    /* in */

	   const int  *xa_begin,    /* in */

	   const int  *xa_end,	    /* in */

	   int	      *marker,	    /* modified */

	   GlobalLU_t *Glu	    /* modified */

	   )

{

    register int i, k, nextl;

    int 	 nsuper, krow, kmark, mem_error;

    int 	 *xsup, *supno;

    int 	 *lsub, *xlsub;

    int 	 nzlmax;

    xsup    = Glu->xsup;

    supno   = Glu->supno;

    lsub    = Glu->lsub;

    xlsub   = Glu->xlsub;

    nzlmax  = Glu->nzlmax;

    nsuper = ++supno[jcol];	/* Next available supernode number */

    nextl = xlsub[jcol];

    for (i = jcol; i <= kcol; i++)

    {

	/* For each nonzero in A[*,i] */

	for (k = xa_begin[i]; k < xa_end[i]; k++)

	{

	    krow = asub[k];

	    kmark = marker[krow];

	    if ( kmark != kcol )

	    { /* First time visit krow */

		marker[krow] = kcol;

		lsub[nextl++] = krow;

		if ( nextl >= nzlmax )

		{

		    if ( (mem_error = zLUMemXpand(jcol, nextl, LSUB, &nzlmax,

			    Glu)) != 0)

			return (mem_error);

		    lsub = Glu->lsub;

		}

	    }

	}

	supno[i] = nsuper;

    }

    /* Supernode > 1 */

    if ( jcol < kcol )

	for (i = jcol+1; i <= kcol; i++) xlsub[i] = nextl;

    xsup[nsuper+1] = kcol + 1;

    supno[kcol+1]  = nsuper;

    xlsub[kcol+1]  = nextl;

    return 0;

}