/* This software was developed by Bruce Hendrickson and Robert Leland   *
 * at Sandia National Laboratories under US Department of Energy        *
 * contract DE-AC04-76DP00789 and is copyrighted by Sandia Corporation. */


/* Make linked list of elements in each set. */
void      make_setlists(setlists, list_ptrs, nsets, subsets, subassign,
	      loc2glob, subnvtxs, first)
int      *setlists;		/* space for linked lists of vertices in sets */
int      *list_ptrs;		/* headers of each linked list */
int       nsets;		/* number of sets being created this step */
short    *subsets;		/* subsets being created at current step */
short    *subassign;		/* assignment for vertices in (sub)graph */
int      *loc2glob;		/* mapping from subgraph to graph numbering */
int       subnvtxs;		/* number of vertices in (sub)graph */
int       first;		/* is this full graph or subgraph? */
{
    int set;			/* set a vertex belongs to */
    int i, j;			/* loop counters */

    if (first) {		/* Don't need to indirect set numbers. */
	for (i=0; i<nsets; i++) {
	    list_ptrs[subsets[i]] = 0;
	}

	for (i=subnvtxs; i; i--) {
	    set = subassign[i];
	    setlists[i] = list_ptrs[set];
	    list_ptrs[set] = i;
	}
    }

    else {
	for (i=0; i<nsets; i++) {
	    list_ptrs[subsets[i]] = 0;
	}

	for (i=subnvtxs; i; i--) {
	    set = subsets[subassign[i]];
	    j = loc2glob[i];
	    setlists[j] = list_ptrs[set];
	    list_ptrs[set] = j;
	}
    }
}