/*
* Copyright 1997, Regents of the University of Minnesota
*
* balance.c
*
* This file contains code that is used to forcefully balance either
* bisections or k-sections
*
* Started 7/29/97
* George
*
* $Id: balance.c,v 1.1 1998/11/27 17:59:10 karypis Exp $
*
*/
#include <metis.h>
/*************************************************************************
* This function is the entry point of the bisection balancing algorithms.
**************************************************************************/
void Balance2Way(CtrlType *ctrl, GraphType *graph, long *tpwgts, float ubfactor)
{
long i, j, nvtxs, from, imax, gain, mindiff;
idxtype *id, *ed;
/* Return right away if the balance is OK */
mindiff = abs(tpwgts[0]-graph->pwgts[0]);
if (mindiff < 3*(graph->pwgts[0]+graph->pwgts[1])/graph->nvtxs)
return;
if (graph->pwgts[0] > tpwgts[0] && graph->pwgts[0] < (long)(ubfactor*tpwgts[0]))
return;
if (graph->pwgts[1] > tpwgts[1] && graph->pwgts[1] < (long)(ubfactor*tpwgts[1]))
return;
if (graph->nbnd > 0)
Bnd2WayBalance(ctrl, graph, tpwgts);
else
General2WayBalance(ctrl, graph, tpwgts);
}
/*************************************************************************
* This function balances two partitions by moving boundary nodes
* from the domain that is overweight to the one that is underweight.
**************************************************************************/
void Bnd2WayBalance(CtrlType *ctrl, GraphType *graph, long *tpwgts)
{
long i, ii, j, k, kwgt, nvtxs, nbnd, nswaps, from, to, pass, me, tmp;
idxtype *xadj, *vwgt, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind, *pwgts;
idxtype *moved, *perm;
PQueueType parts;
long higain, oldgain, mincut, mindiff;
nvtxs = graph->nvtxs;
xadj = graph->xadj;
vwgt = graph->vwgt;
adjncy = graph->adjncy;
adjwgt = graph->adjwgt;
where = graph->where;
id = graph->id;
ed = graph->ed;
pwgts = graph->pwgts;
bndptr = graph->bndptr;
bndind = graph->bndind;
moved = idxwspacemalloc(ctrl, nvtxs);
perm = idxwspacemalloc(ctrl, nvtxs);
/* Determine from which domain you will be moving data */
mindiff = abs(tpwgts[0]-pwgts[0]);
from = (pwgts[0] < tpwgts[0] ? 1 : 0);
to = (from+1)%2;
IFSET(ctrl->dbglvl, DBG_REFINE,
printf("Partitions: [%6ld %6ld] T[%6ld %6ld], Nv-Nb[%6ld %6ld]. ICut: %6ld [B]\n",
pwgts[0], pwgts[1], tpwgts[0], tpwgts[1], graph->nvtxs, graph->nbnd, graph->mincut));
tmp = graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)];
PQueueInit(ctrl, &parts, nvtxs, tmp);
idxset(nvtxs, -1, moved);
ASSERT(ComputeCut(graph, where) == graph->mincut);
ASSERT(CheckBnd(graph));
/* Insert the boundary nodes of the proper partition whose size is OK in the priority queue */
nbnd = graph->nbnd;
RandomPermute(nbnd, perm, 1);
for (ii=0; ii<nbnd; ii++) {
i = perm[ii];
ASSERT(ed[bndind[i]] > 0 || id[bndind[i]] == 0);
ASSERT(bndptr[bndind[i]] != -1);
if (where[bndind[i]] == from && vwgt[bndind[i]] <= mindiff)
PQueueInsert(&parts, bndind[i], ed[bndind[i]]-id[bndind[i]]);
}
mincut = graph->mincut;
for (nswaps=0; nswaps<nvtxs; nswaps++) {
if ((higain = PQueueGetMax(&parts)) == -1)
break;
ASSERT(bndptr[higain] != -1);
if (pwgts[to]+vwgt[higain] > tpwgts[to])
break;
mincut -= (ed[higain]-id[higain]);
INC_DEC(pwgts[to], pwgts[from], vwgt[higain]);
where[higain] = to;
moved[higain] = nswaps;
IFSET(ctrl->dbglvl, DBG_MOVEINFO,
printf("Moved %6ld from %ld. [%3ld %3ld] %5ld [%4ld %4ld]\n", higain, from, ed[higain]-id[higain], vwgt[higain], mincut, pwgts[0], pwgts[1]));
/**************************************************************
* Update the id[i]/ed[i] values of the affected nodes
***************************************************************/
SWAP(id[higain], ed[higain], tmp);
if (ed[higain] == 0 && xadj[higain] < xadj[higain+1])
BNDDelete(nbnd, bndind, bndptr, higain);
for (j=xadj[higain]; j<xadj[higain+1]; j++) {
k = adjncy[j];
oldgain = ed[k]-id[k];
kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]);
INC_DEC(id[k], ed[k], kwgt);
/* Update its boundary information and queue position */
if (bndptr[k] != -1) { /* If k was a boundary vertex */
if (ed[k] == 0) { /* Not a boundary vertex any more */
BNDDelete(nbnd, bndind, bndptr, k);
if (moved[k] == -1 && where[k] == from && vwgt[k] <= mindiff) /* Remove it if in the queues */
PQueueDelete(&parts, k, oldgain);
}
else { /* If it has not been moved, update its position in the queue */
if (moved[k] == -1 && where[k] == from && vwgt[k] <= mindiff)
PQueueUpdate(&parts, k, oldgain, ed[k]-id[k]);
}
}
else {
if (ed[k] > 0) { /* It will now become a boundary vertex */
BNDInsert(nbnd, bndind, bndptr, k);
if (moved[k] == -1 && where[k] == from && vwgt[k] <= mindiff)
PQueueInsert(&parts, k, ed[k]-id[k]);
}
}
}
}
IFSET(ctrl->dbglvl, DBG_REFINE,
printf("\tMinimum cut: %6ld, PWGTS: [%6ld %6ld], NBND: %6ld\n", mincut, pwgts[0], pwgts[1], nbnd));
graph->mincut = mincut;
graph->nbnd = nbnd;
PQueueFree(ctrl, &parts);
idxwspacefree(ctrl, nvtxs);
idxwspacefree(ctrl, nvtxs);
}
/*************************************************************************
* This function balances two partitions by moving the highest gain
* (including negative gain) vertices to the other domain.
* It is used only when tha unbalance is due to non contigous
* subdomains. That is, the are no boundary vertices.
* It moves vertices from the domain that is overweight to the one that
* is underweight.
**************************************************************************/
void General2WayBalance(CtrlType *ctrl, GraphType *graph, long *tpwgts)
{
long i, ii, j, k, kwgt, nvtxs, nbnd, nswaps, from, to, pass, me, tmp;
idxtype *xadj, *vwgt, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind, *pwgts;
idxtype *moved, *perm;
PQueueType parts;
long higain, oldgain, mincut, mindiff;
nvtxs = graph->nvtxs;
xadj = graph->xadj;
vwgt = graph->vwgt;
adjncy = graph->adjncy;
adjwgt = graph->adjwgt;
where = graph->where;
id = graph->id;
ed = graph->ed;
pwgts = graph->pwgts;
bndptr = graph->bndptr;
bndind = graph->bndind;
moved = idxwspacemalloc(ctrl, nvtxs);
perm = idxwspacemalloc(ctrl, nvtxs);
/* Determine from which domain you will be moving data */
mindiff = abs(tpwgts[0]-pwgts[0]);
from = (pwgts[0] < tpwgts[0] ? 1 : 0);
to = (from+1)%2;
IFSET(ctrl->dbglvl, DBG_REFINE,
printf("Partitions: [%6ld %6ld] T[%6ld %6ld], Nv-Nb[%6ld %6ld]. ICut: %6ld [B]\n",
pwgts[0], pwgts[1], tpwgts[0], tpwgts[1], graph->nvtxs, graph->nbnd, graph->mincut));
tmp = graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)];
PQueueInit(ctrl, &parts, nvtxs, tmp);
idxset(nvtxs, -1, moved);
ASSERT(ComputeCut(graph, where) == graph->mincut);
ASSERT(CheckBnd(graph));
/* Insert the nodes of the proper partition whose size is OK in the priority queue */
RandomPermute(nvtxs, perm, 1);
for (ii=0; ii<nvtxs; ii++) {
i = perm[ii];
if (where[i] == from && vwgt[i] <= mindiff)
PQueueInsert(&parts, i, ed[i]-id[i]);
}
mincut = graph->mincut;
nbnd = graph->nbnd;
for (nswaps=0; nswaps<nvtxs; nswaps++) {
if ((higain = PQueueGetMax(&parts)) == -1)
break;
if (pwgts[to]+vwgt[higain] > tpwgts[to])
break;
mincut -= (ed[higain]-id[higain]);
INC_DEC(pwgts[to], pwgts[from], vwgt[higain]);
where[higain] = to;
moved[higain] = nswaps;
IFSET(ctrl->dbglvl, DBG_MOVEINFO,
printf("Moved %6ld from %ld. [%3ld %3ld] %5ld [%4ld %4ld]\n", higain, from, ed[higain]-id[higain], vwgt[higain], mincut, pwgts[0], pwgts[1]));
/**************************************************************
* Update the id[i]/ed[i] values of the affected nodes
***************************************************************/
SWAP(id[higain], ed[higain], tmp);
if (ed[higain] == 0 && bndptr[higain] != -1 && xadj[higain] < xadj[higain+1])
BNDDelete(nbnd, bndind, bndptr, higain);
if (ed[higain] > 0 && bndptr[higain] == -1)
BNDInsert(nbnd, bndind, bndptr, higain);
for (j=xadj[higain]; j<xadj[higain+1]; j++) {
k = adjncy[j];
oldgain = ed[k]-id[k];
kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]);
INC_DEC(id[k], ed[k], kwgt);
/* Update the queue position */
if (moved[k] == -1 && where[k] == from && vwgt[k] <= mindiff)
PQueueUpdate(&parts, k, oldgain, ed[k]-id[k]);
/* Update its boundary information */
if (ed[k] == 0 && bndptr[k] != -1)
BNDDelete(nbnd, bndind, bndptr, k);
else if (ed[k] > 0 && bndptr[k] == -1)
BNDInsert(nbnd, bndind, bndptr, k);
}
}
IFSET(ctrl->dbglvl, DBG_REFINE,
printf("\tMinimum cut: %6ld, PWGTS: [%6ld %6ld], NBND: %6ld\n", mincut, pwgts[0], pwgts[1], nbnd));
graph->mincut = mincut;
graph->nbnd = nbnd;
PQueueFree(ctrl, &parts);
idxwspacefree(ctrl, nvtxs);
idxwspacefree(ctrl, nvtxs);
}
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