/*************************************************************************
* 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 InitPartition(ctrl_t *ctrl, graph_t *graph)
{
idx_t i, j, ncon, mype, npes, gnvtxs, ngroups;
idx_t *xadj, *adjncy, *adjwgt, *vwgt;
idx_t *part, *gwhere0, *gwhere1;
idx_t *tmpwhere, *tmpvwgt, *tmpxadj, *tmpadjncy, *tmpadjwgt;
graph_t *agraph;
idx_t lnparts, fpart, fpe, lnpes;
idx_t twoparts=2, moptions[METIS_NOPTIONS], edgecut, max_cut;
real_t *tpwgts, *tpwgts2, *lbvec, lbsum, min_lbsum, wsum;
MPI_Comm ipcomm;
struct {
double sum;
int rank;
} lpesum, gpesum;
WCOREPUSH;
ncon = graph->ncon;
ngroups = gk_max(gk_min(RIP_SPLIT_FACTOR, ctrl->npes), 1);
IFSET(ctrl->dbglvl, DBG_TIME, gkMPI_Barrier(ctrl->comm));
IFSET(ctrl->dbglvl, DBG_TIME, starttimer(ctrl->InitPartTmr));
lbvec = rwspacemalloc(ctrl, ncon);
/* assemble the graph to all the processors */
agraph = AssembleAdaptiveGraph(ctrl, graph);
gnvtxs = agraph->nvtxs;
/* make a copy of the graph's structure for later */
xadj = icopy(gnvtxs+1, agraph->xadj, iwspacemalloc(ctrl, gnvtxs+1));
vwgt = icopy(gnvtxs*ncon, agraph->vwgt, iwspacemalloc(ctrl, gnvtxs*ncon));
adjncy = icopy(agraph->nedges, agraph->adjncy, iwspacemalloc(ctrl, agraph->nedges));
adjwgt = icopy(agraph->nedges, agraph->adjwgt, iwspacemalloc(ctrl, agraph->nedges));
part = iwspacemalloc(ctrl, gnvtxs);
/* create different processor groups */
gkMPI_Comm_split(ctrl->gcomm, ctrl->mype % ngroups, 0, &ipcomm);
gkMPI_Comm_rank(ipcomm, &mype);
gkMPI_Comm_size(ipcomm, &npes);
/* Go into the recursive bisection */
METIS_SetDefaultOptions(moptions);
moptions[METIS_OPTION_SEED] = ctrl->sync + (ctrl->mype % ngroups) + 1;
tpwgts = ctrl->tpwgts;
tpwgts2 = rwspacemalloc(ctrl, 2*ncon);
lnparts = ctrl->nparts;
fpart = fpe = 0;
lnpes = npes;
while (lnpes > 1 && lnparts > 1) {
/* determine the weights of the two partitions as a function of the
weight of the target partition weights */
for (j=(lnparts>>1), i=0; i<ncon; i++) {
tpwgts2[i] = rsum(j, tpwgts+fpart*ncon+i, ncon);
tpwgts2[ncon+i] = rsum(lnparts-j, tpwgts+(fpart+j)*ncon+i, ncon);
wsum = 1.0/(tpwgts2[i] + tpwgts2[ncon+i]);
tpwgts2[i] *= wsum;
tpwgts2[ncon+i] *= wsum;
}
METIS_PartGraphRecursive(&agraph->nvtxs, &ncon, agraph->xadj, agraph->adjncy,
agraph->vwgt, NULL, agraph->adjwgt, &twoparts, tpwgts2, NULL, moptions,
&edgecut, part);
/* pick one of the branches */
if (mype < fpe+lnpes/2) {
KeepPart(ctrl, agraph, part, 0);
lnpes = lnpes/2;
lnparts = lnparts/2;
}
else {
KeepPart(ctrl, agraph, part, 1);
fpart = fpart + lnparts/2;
fpe = fpe + lnpes/2;
lnpes = lnpes - lnpes/2;
lnparts = lnparts - lnparts/2;
}
}
gwhere0 = iset(gnvtxs, 0, iwspacemalloc(ctrl, gnvtxs));
gwhere1 = iwspacemalloc(ctrl, gnvtxs);
if (lnparts == 1) { /* Case npes is greater than or equal to nparts */
/* 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;
}
}
else { /* Case in which npes is smaller than nparts */
/* create the normalized tpwgts for the lnparts from ctrl->tpwgts */
tpwgts = rwspacemalloc(ctrl, lnparts*ncon);
for (j=0; j<ncon; j++) {
for (wsum=0.0, i=0; i<lnparts; i++) {
tpwgts[i*ncon+j] = ctrl->tpwgts[(fpart+i)*ncon+j];
wsum += tpwgts[i*ncon+j];
}
for (wsum=1.0/wsum, i=0; i<lnparts; i++)
tpwgts[i*ncon+j] *= wsum;
}
METIS_PartGraphKway(&agraph->nvtxs, &ncon, agraph->xadj, agraph->adjncy,
agraph->vwgt, NULL, agraph->adjwgt, &lnparts, tpwgts, NULL, moptions,
&edgecut, part);
for (i=0; i<agraph->nvtxs; i++)
gwhere0[agraph->label[i]] = fpart + part[i];
}
gkMPI_Allreduce((void *)gwhere0, (void *)gwhere1, gnvtxs, IDX_T, 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;
edgecut = ComputeSerialEdgeCut(agraph);
ComputeSerialBalance(ctrl, agraph, gwhere1, lbvec);
lbsum = rsum(ncon, lbvec, 1);
gkMPI_Allreduce((void *)&edgecut, (void *)&max_cut, 1, IDX_T, MPI_MAX, ctrl->gcomm);
gkMPI_Allreduce((void *)&lbsum, (void *)&min_lbsum, 1, REAL_T, MPI_MIN, ctrl->gcomm);
lpesum.sum = lbsum;
if (min_lbsum < UNBALANCE_FRACTION*ncon) {
if (lbsum < UNBALANCE_FRACTION*ncon)
lpesum.sum = edgecut;
else
lpesum.sum = max_cut;
}
lpesum.rank = ctrl->mype;
gkMPI_Allreduce((void *)&lpesum, (void *)&gpesum, 1, MPI_DOUBLE_INT,
MPI_MINLOC, ctrl->gcomm);
gkMPI_Bcast((void *)gwhere1, gnvtxs, IDX_T, gpesum.rank, ctrl->gcomm);
agraph->xadj = tmpxadj;
agraph->adjncy = tmpadjncy;
agraph->adjwgt = tmpadjwgt;
agraph->vwgt = tmpvwgt;
agraph->where = tmpwhere;
}
icopy(graph->nvtxs, gwhere1+graph->vtxdist[ctrl->mype], graph->where);
FreeGraph(agraph);
gkMPI_Comm_free(&ipcomm);
IFSET(ctrl->dbglvl, DBG_TIME, gkMPI_Barrier(ctrl->comm));
IFSET(ctrl->dbglvl, DBG_TIME, stoptimer(ctrl->InitPartTmr));
WCOREPOP;
}
/*************************************************************************
* This function is the entry point of the initial balancing algorithm.
* This algorithm assembles the graph to all the processors and preceeds
* with the balancing step.
**************************************************************************/
void Balance_Partition(ctrl_t *ctrl, graph_t *graph)
{
idx_t i, j, nvtxs, nedges, ncon;
idx_t mype, npes, srnpes, srmype;
idx_t *vtxdist, *xadj, *adjncy, *adjwgt, *vwgt, *vsize;
idx_t *part, *lwhere, *home;
idx_t lnparts, fpart, fpe, lnpes, ngroups;
idx_t *rcounts, *rdispls;
idx_t twoparts=2, moptions[METIS_NOPTIONS], edgecut, max_cut;
idx_t sr_pe, gd_pe, sr, gd, who_wins;
real_t my_cut, my_totalv, my_cost = -1.0, my_balance = -1.0, wsum;
real_t rating, max_rating, your_cost = -1.0, your_balance = -1.0;
real_t lbsum, min_lbsum, *lbvec, *tpwgts, *tpwgts2, buffer[2];
graph_t *agraph, cgraph;
ctrl_t *myctrl;
MPI_Status status;
MPI_Comm ipcomm, srcomm;
struct {
double cost;
int rank;
} lpecost, gpecost;
IFSET(ctrl->dbglvl, DBG_TIME, starttimer(ctrl->InitPartTmr));
WCOREPUSH;
vtxdist = graph->vtxdist;
agraph = AssembleAdaptiveGraph(ctrl, graph);
nvtxs = cgraph.nvtxs = agraph->nvtxs;
nedges = cgraph.nedges = agraph->nedges;
ncon = cgraph.ncon = agraph->ncon;
xadj = cgraph.xadj = icopy(nvtxs+1, agraph->xadj, iwspacemalloc(ctrl, nvtxs+1));
vwgt = cgraph.vwgt = icopy(nvtxs*ncon, agraph->vwgt, iwspacemalloc(ctrl, nvtxs*ncon));
vsize = cgraph.vsize = icopy(nvtxs, agraph->vsize, iwspacemalloc(ctrl, nvtxs));
adjncy = cgraph.adjncy = icopy(nedges, agraph->adjncy, iwspacemalloc(ctrl, nedges));
adjwgt = cgraph.adjwgt = icopy(nedges, agraph->adjwgt, iwspacemalloc(ctrl, nedges));
part = cgraph.where = agraph->where = iwspacemalloc(ctrl, nvtxs);
lwhere = iwspacemalloc(ctrl, nvtxs);
home = iwspacemalloc(ctrl, nvtxs);
lbvec = rwspacemalloc(ctrl, graph->ncon);
/****************************************/
/****************************************/
if (ctrl->ps_relation == PARMETIS_PSR_UNCOUPLED) {
WCOREPUSH;
rcounts = iwspacemalloc(ctrl, ctrl->npes);
rdispls = iwspacemalloc(ctrl, ctrl->npes+1);
for (i=0; i<ctrl->npes; i++)
rdispls[i] = rcounts[i] = vtxdist[i+1]-vtxdist[i];
MAKECSR(i, ctrl->npes, rdispls);
gkMPI_Allgatherv((void *)graph->home, graph->nvtxs, IDX_T,
(void *)part, rcounts, rdispls, IDX_T, ctrl->comm);
for (i=0; i<agraph->nvtxs; i++)
home[i] = part[i];
WCOREPOP; /* local frees */
}
else {
for (i=0; i<ctrl->npes; i++) {
for (j=vtxdist[i]; j<vtxdist[i+1]; j++)
part[j] = home[j] = i;
}
}
/* Ensure that the initial partitioning is legal */
for (i=0; i<agraph->nvtxs; i++) {
if (part[i] >= ctrl->nparts)
part[i] = home[i] = part[i] % ctrl->nparts;
if (part[i] < 0)
part[i] = home[i] = (-1*part[i]) % ctrl->nparts;
}
/****************************************/
/****************************************/
IFSET(ctrl->dbglvl, DBG_REFINEINFO,
ComputeSerialBalance(ctrl, agraph, agraph->where, lbvec));
IFSET(ctrl->dbglvl, DBG_REFINEINFO,
rprintf(ctrl, "input cut: %"PRIDX", balance: ", ComputeSerialEdgeCut(agraph)));
for (i=0; i<agraph->ncon; i++)
IFSET(ctrl->dbglvl, DBG_REFINEINFO, rprintf(ctrl, "%.3"PRREAL" ", lbvec[i]));
IFSET(ctrl->dbglvl, DBG_REFINEINFO, rprintf(ctrl, "\n"));
/****************************************/
/* Split the processors into two groups */
/****************************************/
sr = (ctrl->mype % 2 == 0) ? 1 : 0;
gd = (ctrl->mype % 2 == 1) ? 1 : 0;
if (graph->ncon > MAX_NCON_FOR_DIFFUSION || ctrl->npes == 1) {
sr = 1;
gd = 0;
}
sr_pe = 0;
gd_pe = 1;
gkMPI_Comm_split(ctrl->gcomm, sr, 0, &ipcomm);
gkMPI_Comm_rank(ipcomm, &mype);
gkMPI_Comm_size(ipcomm, &npes);
if (sr == 1) { /* Half of the processors do scratch-remap */
ngroups = gk_max(gk_min(RIP_SPLIT_FACTOR, npes), 1);
gkMPI_Comm_split(ipcomm, mype % ngroups, 0, &srcomm);
gkMPI_Comm_rank(srcomm, &srmype);
gkMPI_Comm_size(srcomm, &srnpes);
METIS_SetDefaultOptions(moptions);
moptions[METIS_OPTION_SEED] = ctrl->sync + (mype % ngroups) + 1;
tpwgts = ctrl->tpwgts;
tpwgts2 = rwspacemalloc(ctrl, 2*ncon);
iset(nvtxs, 0, lwhere);
lnparts = ctrl->nparts;
fpart = fpe = 0;
lnpes = srnpes;
while (lnpes > 1 && lnparts > 1) {
PASSERT(ctrl, agraph->nvtxs > 1);
/* determine the weights of the two partitions as a function of the
weight of the target partition weights */
for (j=(lnparts>>1), i=0; i<ncon; i++) {
tpwgts2[i] = rsum(j, tpwgts+fpart*ncon+i, ncon);
tpwgts2[ncon+i] = rsum(lnparts-j, tpwgts+(fpart+j)*ncon+i, ncon);
wsum = 1.0/(tpwgts2[i] + tpwgts2[ncon+i]);
tpwgts2[i] *= wsum;
tpwgts2[ncon+i] *= wsum;
}
METIS_PartGraphRecursive(&agraph->nvtxs, &ncon, agraph->xadj,
agraph->adjncy, agraph->vwgt, NULL, agraph->adjwgt,
&twoparts, tpwgts2, NULL, moptions, &edgecut, part);
/* pick one of the branches */
if (srmype < fpe+lnpes/2) {
KeepPart(ctrl, agraph, part, 0);
lnpes = lnpes/2;
lnparts = lnparts/2;
}
else {
KeepPart(ctrl, agraph, part, 1);
fpart = fpart + lnparts/2;
fpe = fpe + lnpes/2;
lnpes = lnpes - lnpes/2;
lnparts = lnparts - lnparts/2;
}
}
if (lnparts == 1) { /* Case in which srnpes is greater or equal to nparts */
/* Only the first process will assign labels (for the reduction to work) */
if (srmype == fpe) {
for (i=0; i<agraph->nvtxs; i++)
lwhere[agraph->label[i]] = fpart;
}
}
else { /* Case in which srnpes is smaller than nparts */
/* create the normalized tpwgts for the lnparts from ctrl->tpwgts */
tpwgts = rwspacemalloc(ctrl, lnparts*ncon);
for (j=0; j<ncon; j++) {
for (wsum=0.0, i=0; i<lnparts; i++) {
tpwgts[i*ncon+j] = ctrl->tpwgts[(fpart+i)*ncon+j];
wsum += tpwgts[i*ncon+j];
}
for (wsum=1.0/wsum, i=0; i<lnparts; i++)
tpwgts[i*ncon+j] *= wsum;
}
METIS_PartGraphKway(&agraph->nvtxs, &ncon, agraph->xadj, agraph->adjncy,
agraph->vwgt, NULL, agraph->adjwgt, &lnparts, tpwgts, NULL, moptions,
&edgecut, part);
for (i=0; i<agraph->nvtxs; i++)
lwhere[agraph->label[i]] = fpart + part[i];
}
gkMPI_Allreduce((void *)lwhere, (void *)part, nvtxs, IDX_T, MPI_SUM, srcomm);
edgecut = ComputeSerialEdgeCut(&cgraph);
ComputeSerialBalance(ctrl, &cgraph, part, lbvec);
lbsum = rsum(ncon, lbvec, 1);
gkMPI_Allreduce((void *)&edgecut, (void *)&max_cut, 1, IDX_T, MPI_MAX, ipcomm);
gkMPI_Allreduce((void *)&lbsum, (void *)&min_lbsum, 1, REAL_T, MPI_MIN, ipcomm);
lpecost.rank = ctrl->mype;
lpecost.cost = lbsum;
if (min_lbsum < UNBALANCE_FRACTION * (real_t)(ncon)) {
if (lbsum < UNBALANCE_FRACTION * (real_t)(ncon))
lpecost.cost = (double)edgecut;
else
lpecost.cost = (double)max_cut + lbsum;
}
gkMPI_Allreduce((void *)&lpecost, (void *)&gpecost, 1, MPI_DOUBLE_INT,
MPI_MINLOC, ipcomm);
if (ctrl->mype == gpecost.rank && ctrl->mype != sr_pe)
gkMPI_Send((void *)part, nvtxs, IDX_T, sr_pe, 1, ctrl->comm);
if (ctrl->mype != gpecost.rank && ctrl->mype == sr_pe)
gkMPI_Recv((void *)part, nvtxs, IDX_T, gpecost.rank, 1, ctrl->comm, &status);
if (ctrl->mype == sr_pe) {
icopy(nvtxs, part, lwhere);
SerialRemap(ctrl, &cgraph, ctrl->nparts, home, lwhere, part, ctrl->tpwgts);
}
gkMPI_Comm_free(&srcomm);
}
