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[matrix] View of /pkg/src/Metis/balance.c
 [matrix] / pkg / src / Metis / balance.c

# View of /pkg/src/Metis/balance.c

Revision 10 - (download) (as text) (annotate)
Mon Mar 22 20:20:05 2004 UTC (15 years, 11 months ago) by bates
File size: 9210 byte(s)
`Initial import`
```/*
* 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 2003/12/31 21:32:30 bates Exp \$
*
*/

#include <metis.h>

/*************************************************************************
* This function is the entry point of the bisection balancing algorithms.
**************************************************************************/
void Balance2Way(CtrlType *ctrl, GraphType *graph, int *tpwgts, float ubfactor)
{
int 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] < (int)(ubfactor*tpwgts[0]))
return;
if (graph->pwgts[1] > tpwgts[1] && graph->pwgts[1] < (int)(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, int *tpwgts)
{
int 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;
int 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: [%6d %6d] T[%6d %6d], Nv-Nb[%6d %6d]. ICut: %6d [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 %6d from %d. [%3d %3d] %5d [%4d %4d]\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: %6d, PWGTS: [%6d %6d], NBND: %6d\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, int *tpwgts)
{
int 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;
int 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: [%6d %6d] T[%6d %6d], Nv-Nb[%6d %6d]. ICut: %6d [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 %6d from %d. [%3d %3d] %5d [%4d %4d]\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: %6d, PWGTS: [%6d %6d], NBND: %6d\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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