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2008-04-15 18:56:58 +01:00

253 lines
7.9 KiB
C

/*
* Copyright 1997, Regents of the University of Minnesota
*
* initpart.c
*
* This file contains code that performs log(p) parallel multilevel
* recursive bissection
*
* Started 3/4/96
* George
*
* $Id: initpart.c,v 1.2 2003/07/21 17:18:49 karypis Exp $
*/
#include <parmetislib.h>
#define DEBUG_IPART_
/*************************************************************************
* This function is the entry point of the initial partition algorithm
* that does recursive bissection.
* This algorithm assembles the graph to all the processors and preceeds
* by parallelizing the recursive bisection step.
**************************************************************************/
void Moc_InitPartition_RB(CtrlType *ctrl, GraphType *graph, WorkSpaceType *wspace)
{
int i, j;
int ncon, mype, npes, gnvtxs, ngroups;
idxtype *xadj, *adjncy, *adjwgt, *vwgt;
idxtype *part, *gwhere0, *gwhere1;
idxtype *tmpwhere, *tmpvwgt, *tmpxadj, *tmpadjncy, *tmpadjwgt;
GraphType *agraph;
int lnparts, fpart, fpe, lnpes;
int twoparts=2, numflag = 0, wgtflag = 3, moptions[10], edgecut, max_cut;
float *mytpwgts, mytpwgts2[2], lbvec[MAXNCON], lbsum, min_lbsum, wsum;
MPI_Comm ipcomm;
struct {
float sum;
int rank;
} lpesum, gpesum;
ncon = graph->ncon;
ngroups = amax(amin(RIP_SPLIT_FACTOR, ctrl->npes), 1);
IFSET(ctrl->dbglvl, DBG_TIME, MPI_Barrier(ctrl->comm));
IFSET(ctrl->dbglvl, DBG_TIME, starttimer(ctrl->InitPartTmr));
agraph = Moc_AssembleAdaptiveGraph(ctrl, graph, wspace);
part = idxmalloc(agraph->nvtxs, "Moc_IP_RB: part");
xadj = idxmalloc(agraph->nvtxs+1, "Moc_IP_RB: xadj");
adjncy = idxmalloc(agraph->nedges, "Moc_IP_RB: adjncy");
adjwgt = idxmalloc(agraph->nedges, "Moc_IP_RB: adjwgt");
vwgt = idxmalloc(agraph->nvtxs*ncon, "Moc_IP_RB: vwgt");
idxcopy(agraph->nvtxs*ncon, agraph->vwgt, vwgt);
idxcopy(agraph->nvtxs+1, agraph->xadj, xadj);
idxcopy(agraph->nedges, agraph->adjncy, adjncy);
idxcopy(agraph->nedges, agraph->adjwgt, adjwgt);
MPI_Comm_split(ctrl->gcomm, ctrl->mype % ngroups, 0, &ipcomm);
MPI_Comm_rank(ipcomm, &mype);
MPI_Comm_size(ipcomm, &npes);
gnvtxs = agraph->nvtxs;
gwhere0 = idxsmalloc(gnvtxs, 0, "Moc_IP_RB: gwhere0");
gwhere1 = idxmalloc(gnvtxs, "Moc_IP_RB: gwhere1");
/* ADD: this assumes that tpwgts for all constraints is the same */
/* ADD: this is necessary because serial metis does not support the general case */
mytpwgts = fsmalloc(ctrl->nparts, 0.0, "mytpwgts");
for (i=0; i<ctrl->nparts; i++)
for (j=0; j<ncon; j++)
mytpwgts[i] += ctrl->tpwgts[i*ncon+j];
for (i=0; i<ctrl->nparts; i++)
mytpwgts[i] /= (float)ncon;
/* Go into the recursive bisection */
/* ADD: consider changing this to breadth-first type bisection */
moptions[0] = 0;
moptions[7] = ctrl->sync + (ctrl->mype % ngroups) + 1;
lnparts = ctrl->nparts;
fpart = fpe = 0;
lnpes = npes;
while (lnpes > 1 && lnparts > 1) {
/* Determine the weights of the partitions */
mytpwgts2[0] = ssum(lnparts/2, mytpwgts+fpart);
mytpwgts2[1] = 1.0-mytpwgts2[0];
if (ncon == 1)
METIS_WPartGraphKway2(&agraph->nvtxs, agraph->xadj, agraph->adjncy,
agraph->vwgt, agraph->adjwgt, &wgtflag, &numflag, &twoparts, mytpwgts2,
moptions, &edgecut, part);
else {
METIS_mCPartGraphRecursive2(&agraph->nvtxs, &ncon, agraph->xadj,
agraph->adjncy, agraph->vwgt, agraph->adjwgt, &wgtflag, &numflag,
&twoparts, mytpwgts2, moptions, &edgecut, part);
}
wsum = ssum(lnparts/2, mytpwgts+fpart);
sscale(lnparts/2, 1.0/wsum, mytpwgts+fpart);
sscale(lnparts-lnparts/2, 1.0/(1.0-wsum), mytpwgts+fpart+lnparts/2);
/* I'm picking the left branch */
if (mype < fpe+lnpes/2) {
Moc_KeepPart(agraph, wspace, part, 0);
lnpes = lnpes/2;
lnparts = lnparts/2;
}
else {
Moc_KeepPart(agraph, wspace, part, 1);
fpart = fpart + lnparts/2;
fpe = fpe + lnpes/2;
lnpes = lnpes - lnpes/2;
lnparts = lnparts - lnparts/2;
}
}
/* In case npes is greater than or equal to nparts */
if (lnparts == 1) {
/* Only the first process will assign labels (for the reduction to work) */
if (mype == fpe) {
for (i=0; i<agraph->nvtxs; i++)
gwhere0[agraph->label[i]] = fpart;
}
}
/* In case npes is smaller than nparts */
else {
if (ncon == 1)
METIS_WPartGraphKway2(&agraph->nvtxs, agraph->xadj, agraph->adjncy,
agraph->vwgt, agraph->adjwgt, &wgtflag, &numflag, &lnparts, mytpwgts+fpart,
moptions, &edgecut, part);
else
METIS_mCPartGraphRecursive2(&agraph->nvtxs, &ncon, agraph->xadj,
agraph->adjncy, agraph->vwgt, agraph->adjwgt, &wgtflag, &numflag,
&lnparts, mytpwgts+fpart, moptions, &edgecut, part);
for (i=0; i<agraph->nvtxs; i++)
gwhere0[agraph->label[i]] = fpart + part[i];
}
MPI_Allreduce((void *)gwhere0, (void *)gwhere1, gnvtxs, IDX_DATATYPE, MPI_SUM, ipcomm);
if (ngroups > 1) {
tmpxadj = agraph->xadj;
tmpadjncy = agraph->adjncy;
tmpadjwgt = agraph->adjwgt;
tmpvwgt = agraph->vwgt;
tmpwhere = agraph->where;
agraph->xadj = xadj;
agraph->adjncy = adjncy;
agraph->adjwgt = adjwgt;
agraph->vwgt = vwgt;
agraph->where = gwhere1;
agraph->vwgt = vwgt;
agraph->nvtxs = gnvtxs;
Moc_ComputeSerialBalance(ctrl, agraph, gwhere1, lbvec);
lbsum = ssum(ncon, lbvec);
edgecut = ComputeSerialEdgeCut(agraph);
MPI_Allreduce((void *)&edgecut, (void *)&max_cut, 1, MPI_INT, MPI_MAX, ctrl->gcomm);
MPI_Allreduce((void *)&lbsum, (void *)&min_lbsum, 1, MPI_FLOAT, MPI_MIN, ctrl->gcomm);
lpesum.sum = lbsum;
if (min_lbsum < UNBALANCE_FRACTION * (float)(ncon)) {
if (lbsum < UNBALANCE_FRACTION * (float)(ncon))
lpesum.sum = (float) (edgecut);
else
lpesum.sum = (float) (max_cut);
}
MPI_Comm_rank(ctrl->gcomm, &(lpesum.rank));
MPI_Allreduce((void *)&lpesum, (void *)&gpesum, 1, MPI_FLOAT_INT, MPI_MINLOC, ctrl->gcomm);
MPI_Bcast((void *)gwhere1, gnvtxs, IDX_DATATYPE, gpesum.rank, ctrl->gcomm);
agraph->xadj = tmpxadj;
agraph->adjncy = tmpadjncy;
agraph->adjwgt = tmpadjwgt;
agraph->vwgt = tmpvwgt;
agraph->where = tmpwhere;
}
idxcopy(graph->nvtxs, gwhere1+graph->vtxdist[ctrl->mype], graph->where);
FreeGraph(agraph);
MPI_Comm_free(&ipcomm);
GKfree((void **)&gwhere0, (void **)&gwhere1, (void **)&mytpwgts, (void **)&part, (void **)&xadj, (void **)&adjncy, (void **)&adjwgt, (void **)&vwgt, LTERM);
IFSET(ctrl->dbglvl, DBG_TIME, MPI_Barrier(ctrl->comm));
IFSET(ctrl->dbglvl, DBG_TIME, stoptimer(ctrl->InitPartTmr));
}
/*************************************************************************
* This function keeps one parts
**************************************************************************/
void Moc_KeepPart(GraphType *graph, WorkSpaceType *wspace, idxtype *part, int mypart)
{
int h, i, j, k;
int nvtxs, ncon, mynvtxs, mynedges;
idxtype *xadj, *vwgt, *adjncy, *adjwgt, *label;
idxtype *rename;
nvtxs = graph->nvtxs;
ncon = graph->ncon;
xadj = graph->xadj;
vwgt = graph->vwgt;
adjncy = graph->adjncy;
adjwgt = graph->adjwgt;
label = graph->label;
rename = idxmalloc(nvtxs, "Moc_KeepPart: rename");
for (mynvtxs=0, i=0; i<nvtxs; i++) {
if (part[i] == mypart)
rename[i] = mynvtxs++;
}
for (mynvtxs=0, mynedges=0, j=xadj[0], i=0; i<nvtxs; i++) {
if (part[i] == mypart) {
for (; j<xadj[i+1]; j++) {
k = adjncy[j];
if (part[k] == mypart) {
adjncy[mynedges] = rename[k];
adjwgt[mynedges++] = adjwgt[j];
}
}
j = xadj[i+1]; /* Save xadj[i+1] for later use */
for (h=0; h<ncon; h++)
vwgt[mynvtxs*ncon+h] = vwgt[i*ncon+h];
label[mynvtxs] = label[i];
xadj[++mynvtxs] = mynedges;
}
else {
j = xadj[i+1]; /* Save xadj[i+1] for later use */
}
}
graph->nvtxs = mynvtxs;
graph->nedges = mynedges;
free(rename);
}