void MlevelNodeBisectionL2(ctrl_t *ctrl, graph_t *graph, idx_t niparts)
{
idx_t i, mincut, nruns=5;
graph_t *cgraph;
idx_t *bestwhere;
/* if the graph is small, just find a single vertex separator */
if (graph->nvtxs < 5000) {
MlevelNodeBisectionL1(ctrl, graph, niparts);
return;
}
WCOREPUSH;
ctrl->CoarsenTo = gk_max(100, graph->nvtxs/30);
cgraph = CoarsenGraphNlevels(ctrl, graph, 4);
bestwhere = iwspacemalloc(ctrl, cgraph->nvtxs);
mincut = graph->tvwgt[0];
for (i=0; i<nruns; i++) {
MlevelNodeBisectionL1(ctrl, cgraph, 0.7*niparts);
if (i == 0 || cgraph->mincut < mincut) {
mincut = cgraph->mincut;
if (i < nruns-1)
icopy(cgraph->nvtxs, cgraph->where, bestwhere);
}
if (mincut == 0)
break;
if (i < nruns-1)
FreeRData(cgraph);
}
if (mincut != cgraph->mincut)
icopy(cgraph->nvtxs, bestwhere, cgraph->where);
WCOREPOP;
Refine2WayNode(ctrl, graph, cgraph);
}
void MlevelNodeBisectionMultiple(ctrl_t *ctrl, graph_t *graph)
{
idx_t i, mincut;
idx_t *bestwhere;
/* if the graph is small, just find a single vertex separator */
if (ctrl->nseps == 1 || graph->nvtxs < (ctrl->compress ? 1000 : 2000)) {
MlevelNodeBisectionL2(ctrl, graph, LARGENIPARTS);
return;
}
WCOREPUSH;
bestwhere = iwspacemalloc(ctrl, graph->nvtxs);
mincut = graph->tvwgt[0];
for (i=0; i<ctrl->nseps; i++) {
MlevelNodeBisectionL2(ctrl, graph, LARGENIPARTS);
if (i == 0 || graph->mincut < mincut) {
mincut = graph->mincut;
if (i < ctrl->nseps-1)
icopy(graph->nvtxs, graph->where, bestwhere);
}
if (mincut == 0)
break;
if (i < ctrl->nseps-1)
FreeRData(graph);
}
if (mincut != graph->mincut) {
icopy(graph->nvtxs, bestwhere, graph->where);
Compute2WayNodePartitionParams(ctrl, graph);
}
WCOREPOP;
}
idx_t MlevelKWayPartitioning(ctrl_t *ctrl, graph_t *graph, idx_t *part)
{
idx_t i, objval=0, curobj=0, bestobj=0;
real_t curbal=0.0, bestbal=0.0;
graph_t *cgraph;
for (i=0; i<ctrl->ncuts; i++) {
cgraph = CoarsenGraph(ctrl, graph);
IFSET(ctrl->dbglvl, METIS_DBG_TIME, gk_startwctimer(ctrl->InitPartTmr));
AllocateKWayPartitionMemory(ctrl, cgraph);
/* Compute the initial partitioning */
switch (ctrl->iptype) {
case METIS_IPTYPE_METISRB:
FreeWorkSpace(ctrl); /* Release the work space, for the recursive metis call */
InitKWayPartitioningRB(ctrl, cgraph);
AllocateWorkSpace(ctrl, graph); /* Re-allocate the work space */
break;
case METIS_IPTYPE_GROW:
AllocateRefinementWorkSpace(ctrl, 2*cgraph->nedges);
InitKWayPartitioningGrow(ctrl, cgraph);
break;
default:
gk_errexit(SIGERR, "Unknown iptype: %d\n", ctrl->iptype);
}
IFSET(ctrl->dbglvl, METIS_DBG_TIME, gk_stopwctimer(ctrl->InitPartTmr));
IFSET(ctrl->dbglvl, METIS_DBG_IPART, printf("Initial %"PRIDX \
"-way partitioning cut: %"PRIDX"\n", ctrl->nparts, objval));
RefineKWay(ctrl, graph, cgraph);
switch (ctrl->objtype) {
case METIS_OBJTYPE_CUT:
curobj = graph->mincut;
break;
case METIS_OBJTYPE_VOL:
curobj = graph->minvol;
break;
default:
gk_errexit(SIGERR, "Unknown objtype: %d\n", ctrl->objtype);
}
curbal = ComputeLoadImbalanceDiff(graph, ctrl->nparts, ctrl->pijbm, ctrl->ubfactors);
if (i == 0
|| (curbal <= 0.0005 && bestobj > curobj)
|| (bestbal > 0.0005 && curbal < bestbal)) {
icopy(graph->nvtxs, graph->where, part);
bestobj = curobj;
bestbal = curbal;
}
FreeRData(graph);
if (bestobj == 0)
break;
}
FreeGraph(&graph);
return bestobj;
}
