Charm++: Charm Source Code Documentation

00001 /*
00002  * Copyright 1997, Regents of the University of Minnesota
00003  *
00004  * mbalance2.c
00005  *
00006  * This file contains code that is used to forcefully balance either
00007  * bisections or k-sections
00008  *
00009  * Started 7/29/97
00010  * George
00011  *
00012  * $Id$
00013  *
00014  */
00015 
00016 #include <metis.h>
00017 
00018 
00019 /*************************************************************************
00020 * This function is the entry point of the bisection balancing algorithms.
00021 **************************************************************************/
00022 void MocBalance2Way2(CtrlType *ctrl, GraphType *graph, floattype *tpwgts, floattype *ubvec)
00023 {
00024   int i;
00025   floattype tvec[MAXNCON];
00026 
00027   Compute2WayHLoadImbalanceVec(graph->ncon, graph->npwgts, tpwgts, tvec);
00028   if (!AreAllBelow(graph->ncon, tvec, ubvec))
00029     MocGeneral2WayBalance2(ctrl, graph, tpwgts, ubvec);
00030 }
00031 
00032 
00033 
00034 /*************************************************************************
00035 * This function performs an edge-based FM refinement
00036 **************************************************************************/
00037 void MocGeneral2WayBalance2(CtrlType *ctrl, GraphType *graph, floattype *tpwgts, floattype *ubvec)
00038 {
00039   int i, ii, j, k, l, kwgt, nvtxs, ncon, nbnd, nswaps, from, to, pass, me, limit, tmp, cnum;
00040   idxtype *xadj, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind;
00041   idxtype *moved, *swaps, *perm, *qnum;
00042   floattype *nvwgt, *npwgts, origbal[MAXNCON], minbal[MAXNCON], newbal[MAXNCON];
00043   PQueueType parts[MAXNCON][2];
00044   int higain, oldgain, mincut, newcut, mincutorder;
00045   floattype *maxwgt, *minwgt, tvec[MAXNCON];
00046 
00047 
00048   nvtxs = graph->nvtxs;
00049   ncon = graph->ncon;
00050   xadj = graph->xadj;
00051   nvwgt = graph->nvwgt;
00052   adjncy = graph->adjncy;
00053   adjwgt = graph->adjwgt;
00054   where = graph->where;
00055   id = graph->id;
00056   ed = graph->ed;
00057   npwgts = graph->npwgts;
00058   bndptr = graph->bndptr;
00059   bndind = graph->bndind;
00060 
00061   moved = idxwspacemalloc(ctrl, nvtxs);
00062   swaps = idxwspacemalloc(ctrl, nvtxs);
00063   perm = idxwspacemalloc(ctrl, nvtxs);
00064   qnum = idxwspacemalloc(ctrl, nvtxs);
00065 
00066   limit = amin(amax(0.01*nvtxs, 15), 100);
00067 
00068   /* Setup the weight intervals of the two subdomains */
00069   minwgt = fwspacemalloc(ctrl, 2*ncon);
00070   maxwgt = fwspacemalloc(ctrl, 2*ncon);
00071 
00072   for (i=0; i<2; i++) {
00073     for (j=0; j<ncon; j++) {
00074       maxwgt[i*ncon+j] = tpwgts[i]*ubvec[j];
00075       minwgt[i*ncon+j] = tpwgts[i]*(1.0/ubvec[j]);
00076     }
00077   }
00078 
00079 
00080   /* Initialize the queues */
00081   for (i=0; i<ncon; i++) {
00082     PQueueInit(ctrl, &parts[i][0], nvtxs, PLUS_GAINSPAN+1);
00083     PQueueInit(ctrl, &parts[i][1], nvtxs, PLUS_GAINSPAN+1);
00084   }
00085   for (i=0; i<nvtxs; i++)
00086     qnum[i] = samax(ncon, nvwgt+i*ncon);
00087 
00088   Compute2WayHLoadImbalanceVec(ncon, npwgts, tpwgts, origbal);
00089   for (i=0; i<ncon; i++) 
00090     minbal[i] = origbal[i];
00091 
00092   newcut = mincut = graph->mincut;
00093   mincutorder = -1;
00094 
00095   if (ctrl->dbglvl&DBG_REFINE) {
00096     printf("Parts: [");
00097     for (l=0; l<ncon; l++)
00098       printf("(%.3f, %.3f) ", npwgts[l], npwgts[ncon+l]);
00099     printf("] T[%.3f %.3f], Nv-Nb[%5d, %5d]. ICut: %6d, LB: ", tpwgts[0], tpwgts[1], 
00100             graph->nvtxs, graph->nbnd, graph->mincut);
00101     for (i=0; i<ncon; i++)
00102       printf("%.3f ", origbal[i]);
00103     printf("[B]\n");
00104   }
00105 
00106   idxset(nvtxs, -1, moved);
00107 
00108   ASSERT(ComputeCut(graph, where) == graph->mincut);
00109   ASSERT(CheckBnd(graph));
00110 
00111   /* Insert all nodes in the priority queues */
00112   nbnd = graph->nbnd;
00113   RandomPermute(nvtxs, perm, 1);
00114   for (ii=0; ii<nvtxs; ii++) {
00115     i = perm[ii];
00116     PQueueInsert(&parts[qnum[i]][where[i]], i, ed[i]-id[i]);
00117   }
00118 
00119 
00120   for (nswaps=0; nswaps<nvtxs; nswaps++) {
00121     if (AreAllBelow(ncon, minbal, ubvec))
00122       break;
00123 
00124     SelectQueue3(ncon, npwgts, tpwgts, &from, &cnum, parts, maxwgt);
00125     to = (from+1)%2;
00126 
00127     if (from == -1 || (higain = PQueueGetMax(&parts[cnum][from])) == -1)
00128       break;
00129 
00130     saxpy(ncon, 1.0, nvwgt+higain*ncon, 1, npwgts+to*ncon, 1);
00131     saxpy(ncon, -1.0, nvwgt+higain*ncon, 1, npwgts+from*ncon, 1);
00132     newcut -= (ed[higain]-id[higain]);
00133     Compute2WayHLoadImbalanceVec(ncon, npwgts, tpwgts, newbal);
00134 
00135     if (IsBetter2wayBalance(ncon, newbal, minbal, ubvec) || 
00136         (IsBetter2wayBalance(ncon, newbal, origbal, ubvec) && newcut < mincut)) {
00137       mincut = newcut;
00138       for (i=0; i<ncon; i++) 
00139         minbal[i] = newbal[i];
00140       mincutorder = nswaps;
00141     }
00142     else if (nswaps-mincutorder > limit) { /* We hit the limit, undo last move */
00143       newcut += (ed[higain]-id[higain]);
00144       saxpy(ncon, 1.0, nvwgt+higain*ncon, 1, npwgts+from*ncon, 1);
00145       saxpy(ncon, -1.0, nvwgt+higain*ncon, 1, npwgts+to*ncon, 1);
00146       break;
00147     }
00148 
00149     where[higain] = to;
00150     moved[higain] = nswaps;
00151     swaps[nswaps] = higain;
00152 
00153     if (ctrl->dbglvl&DBG_MOVEINFO) {
00154       printf("Moved %6d from %d(%d). Gain: %5d, Cut: %5d, NPwgts: ", higain, from, cnum, ed[higain]-id[higain], newcut);
00155       for (i=0; i<ncon; i++) 
00156         printf("(%.3f, %.3f) ", npwgts[i], npwgts[ncon+i]);
00157 
00158       Compute2WayHLoadImbalanceVec(ncon, npwgts, tpwgts, tvec);
00159       printf(", LB: ");
00160       for (i=0; i<ncon; i++) 
00161         printf("%.3f ", tvec[i]);
00162       if (mincutorder == nswaps)
00163         printf(" *\n");
00164       else
00165         printf("\n");
00166     }
00167 
00168 
00169     /**************************************************************
00170     * Update the id[i]/ed[i] values of the affected nodes
00171     ***************************************************************/
00172     SWAP(id[higain], ed[higain], tmp);
00173     if (ed[higain] == 0 && bndptr[higain] != -1 && xadj[higain] < xadj[higain+1]) 
00174       BNDDelete(nbnd, bndind,  bndptr, higain);
00175     if (ed[higain] > 0 && bndptr[higain] == -1)
00176       BNDInsert(nbnd, bndind,  bndptr, higain);
00177 
00178     for (j=xadj[higain]; j<xadj[higain+1]; j++) {
00179       k = adjncy[j];
00180       oldgain = ed[k]-id[k];
00181 
00182       kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]);
00183       INC_DEC(id[k], ed[k], kwgt);
00184 
00185       /* Update the queue position */
00186       if (moved[k] == -1)
00187         PQueueUpdate(&parts[qnum[k]][where[k]], k, oldgain, ed[k]-id[k]);
00188 
00189       /* Update its boundary information */
00190       if (ed[k] == 0 && bndptr[k] != -1) 
00191         BNDDelete(nbnd, bndind, bndptr, k);
00192       else if (ed[k] > 0 && bndptr[k] == -1)  
00193         BNDInsert(nbnd, bndind, bndptr, k);
00194     }
00195    
00196   }
00197 
00198 
00199 
00200   /****************************************************************
00201   * Roll back computations
00202   *****************************************************************/
00203   for (i=0; i<nswaps; i++)
00204     moved[swaps[i]] = -1;  /* reset moved array */
00205   for (nswaps--; nswaps>mincutorder; nswaps--) {
00206     higain = swaps[nswaps];
00207 
00208     to = where[higain] = (where[higain]+1)%2;
00209     SWAP(id[higain], ed[higain], tmp);
00210     if (ed[higain] == 0 && bndptr[higain] != -1 && xadj[higain] < xadj[higain+1])
00211       BNDDelete(nbnd, bndind,  bndptr, higain);
00212     else if (ed[higain] > 0 && bndptr[higain] == -1)
00213       BNDInsert(nbnd, bndind,  bndptr, higain);
00214 
00215     saxpy(ncon, 1.0, nvwgt+higain*ncon, 1, npwgts+to*ncon, 1);
00216     saxpy(ncon, -1.0, nvwgt+higain*ncon, 1, npwgts+((to+1)%2)*ncon, 1);
00217     for (j=xadj[higain]; j<xadj[higain+1]; j++) {
00218       k = adjncy[j];
00219 
00220       kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]);
00221       INC_DEC(id[k], ed[k], kwgt);
00222 
00223       if (bndptr[k] != -1 && ed[k] == 0)
00224         BNDDelete(nbnd, bndind, bndptr, k);
00225       if (bndptr[k] == -1 && ed[k] > 0)
00226         BNDInsert(nbnd, bndind, bndptr, k);
00227     }
00228   }
00229 
00230   if (ctrl->dbglvl&DBG_REFINE) {
00231     printf("\tMincut: %6d at %5d, NBND: %6d, NPwgts: [", mincut, mincutorder, nbnd);
00232     for (i=0; i<ncon; i++)
00233       printf("(%.3f, %.3f) ", npwgts[i], npwgts[ncon+i]);
00234     printf("], LB: ");
00235     Compute2WayHLoadImbalanceVec(ncon, npwgts, tpwgts, tvec);
00236     for (i=0; i<ncon; i++) 
00237       printf("%.3f ", tvec[i]);
00238     printf("\n");
00239   }
00240 
00241   graph->mincut = mincut;
00242   graph->nbnd = nbnd;
00243 
00244 
00245   for (i=0; i<ncon; i++) {
00246     PQueueFree(ctrl, &parts[i][0]);
00247     PQueueFree(ctrl, &parts[i][1]);
00248   }
00249 
00250   idxwspacefree(ctrl, nvtxs);
00251   idxwspacefree(ctrl, nvtxs);
00252   idxwspacefree(ctrl, nvtxs);
00253   idxwspacefree(ctrl, nvtxs);
00254   fwspacefree(ctrl, 2*ncon);
00255   fwspacefree(ctrl, 2*ncon);
00256 
00257 }
00258 
00259 
00260 
00261 
00262 /*************************************************************************
00263 * This function selects the partition number and the queue from which
00264 * we will move vertices out
00265 **************************************************************************/ 
00266 void SelectQueue3(int ncon, floattype *npwgts, floattype *tpwgts, int *from, int *cnum, 
00267        PQueueType queues[MAXNCON][2], floattype *maxwgt)
00268 {
00269   int i, j, maxgain=0;
00270   floattype maxdiff=0.0, diff;
00271 
00272   *from = -1;
00273   *cnum = -1;
00274 
00275   /* First determine the side and the queue, irrespective of the presence of nodes */
00276   for (j=0; j<2; j++) {
00277     for (i=0; i<ncon; i++) {
00278       diff = npwgts[j*ncon+i]-maxwgt[j*ncon+i];
00279       if (diff >= maxdiff) {
00280         maxdiff = diff;
00281         *from = j;
00282         *cnum = i;
00283       }
00284     }
00285   }
00286 
00287 /* DELETE
00288 j = *from;
00289 for (i=0; i<ncon; i++)
00290   printf("[%5d %5d %.4f %.4f] ", i, PQueueGetSize(&queues[i][j]), npwgts[j*ncon+i], maxwgt[j*ncon+i]);
00291 printf("***[%5d %5d]\n", *cnum, *from);
00292 */
00293 
00294   /* If the desired queue is empty, select a node from that side anyway */
00295   if (*from != -1 && PQueueGetSize(&queues[*cnum][*from]) == 0) {
00296     for (i=0; i<ncon; i++) {
00297       if (PQueueGetSize(&queues[i][*from]) > 0) {
00298         maxdiff = (npwgts[(*from)*ncon+i] - maxwgt[(*from)*ncon+i]);
00299         *cnum = i;
00300         break;
00301       }
00302     }
00303 
00304     for (i++; i<ncon; i++) {
00305       diff = npwgts[(*from)*ncon+i] - maxwgt[(*from)*ncon+i];
00306       if (diff > maxdiff && PQueueGetSize(&queues[i][*from]) > 0) {
00307         maxdiff = diff;
00308         *cnum = i;
00309       }
00310     }
00311   }
00312 
00313   /* If the constraints ar OK, select a high gain vertex */
00314   if (*from == -1) {
00315     maxgain = -100000;
00316     for (j=0; j<2; j++) {
00317       for (i=0; i<ncon; i++) {
00318         if (PQueueGetSize(&queues[i][j]) > 0 && PQueueGetKey(&queues[i][j]) > maxgain) {
00319           maxgain = PQueueGetKey(&queues[i][0]); 
00320           *from = j;
00321           *cnum = i;
00322         }
00323       }
00324     }
00325 
00326     /* printf("(%2d %2d) %3d\n", *from, *cnum, maxgain); */
00327   }
00328 }
libs/ck-libs/parmetis/METISLib/mbalance2.c
