Charm++: Charm Source Code Documentation

00001 /*
00002  * Copyright 1997, Regents of the University of Minnesota
00003  *
00004  * pmetis.c
00005  *
00006  * This file contains the top level routines for the multilevel recursive
00007  * bisection algorithm PMETIS.
00008  *
00009  * Started 7/24/97
00010  * George
00011  *
00012  * $Id$
00013  *
00014  */
00015 
00016 #include <metis.h>
00017 
00018 
00019 /*************************************************************************
00020 * This function is the entry point for PMETIS
00021 **************************************************************************/
00022 void METIS_PartGraphRecursive(int *nvtxs, idxtype *xadj, idxtype *adjncy, idxtype *vwgt, 
00023                               idxtype *adjwgt, int *wgtflag, int *numflag, int *nparts, 
00024                               int *options, int *edgecut, idxtype *part)
00025 {
00026   int i;
00027   floattype *tpwgts;
00028 
00029   tpwgts = fmalloc(*nparts, "KMETIS: tpwgts");
00030   for (i=0; i<*nparts; i++) 
00031     tpwgts[i] = 1.0/(1.0*(*nparts));
00032 
00033   METIS_WPartGraphRecursive(nvtxs, xadj, adjncy, vwgt, adjwgt, wgtflag, numflag, nparts, 
00034                             tpwgts, options, edgecut, part);
00035 
00036   free(tpwgts);
00037 }
00038 
00039 
00040 
00041 /*************************************************************************
00042 * This function is the entry point for PWMETIS that accepts exact weights
00043 * for the target partitions
00044 **************************************************************************/
00045 void METIS_WPartGraphRecursive(int *nvtxs, idxtype *xadj, idxtype *adjncy, idxtype *vwgt, 
00046                                idxtype *adjwgt, int *wgtflag, int *numflag, int *nparts, 
00047                                floattype *tpwgts, int *options, int *edgecut, idxtype *part)
00048 {
00049   int i, j;
00050   GraphType graph;
00051   CtrlType ctrl;
00052   floattype *mytpwgts;
00053 
00054   if (*numflag == 1)
00055     Change2CNumbering(*nvtxs, xadj, adjncy);
00056 
00057   SetUpGraph(&graph, OP_PMETIS, *nvtxs, 1, xadj, adjncy, vwgt, adjwgt, *wgtflag);
00058 
00059   if (options[0] == 0) {  /* Use the default parameters */
00060     ctrl.CType = PMETIS_CTYPE;
00061     ctrl.IType = PMETIS_ITYPE;
00062     ctrl.RType = PMETIS_RTYPE;
00063     ctrl.dbglvl = PMETIS_DBGLVL;
00064   }
00065   else {
00066     ctrl.CType = options[OPTION_CTYPE];
00067     ctrl.IType = options[OPTION_ITYPE];
00068     ctrl.RType = options[OPTION_RTYPE];
00069     ctrl.dbglvl = options[OPTION_DBGLVL];
00070   }
00071   ctrl.optype = OP_PMETIS;
00072   ctrl.CoarsenTo = 20;
00073   ctrl.maxvwgt = 1.5*(idxsum(*nvtxs, graph.vwgt)/ctrl.CoarsenTo);
00074 
00075   mytpwgts = fmalloc(*nparts, "PWMETIS: mytpwgts");
00076   for (i=0; i<*nparts; i++) 
00077     mytpwgts[i] = tpwgts[i];
00078 
00079   InitRandom(-1);
00080 
00081   AllocateWorkSpace(&ctrl, &graph, *nparts);
00082 
00083   IFSET(ctrl.dbglvl, DBG_TIME, InitTimers(&ctrl));
00084   IFSET(ctrl.dbglvl, DBG_TIME, starttimer(ctrl.TotalTmr));
00085 
00086   *edgecut = MlevelRecursiveBisection(&ctrl, &graph, *nparts, part, mytpwgts, 1.000, 0);
00087 
00088   IFSET(ctrl.dbglvl, DBG_TIME, stoptimer(ctrl.TotalTmr));
00089   IFSET(ctrl.dbglvl, DBG_TIME, PrintTimers(&ctrl));
00090 
00091   FreeWorkSpace(&ctrl, &graph);
00092   free(mytpwgts);
00093 
00094   if (*numflag == 1)
00095     Change2FNumbering(*nvtxs, xadj, adjncy, part);
00096 }
00097 
00098 
00099 
00100 /*************************************************************************
00101 * This function takes a graph and produces a bisection of it
00102 **************************************************************************/
00103 int MlevelRecursiveBisection(CtrlType *ctrl, GraphType *graph, int nparts, idxtype *part, floattype *tpwgts, floattype ubfactor, int fpart)
00104 {
00105   int i, j, nvtxs, cut, tvwgt, tpwgts2[2];
00106   idxtype *label, *where;
00107   GraphType lgraph, rgraph;
00108   floattype wsum;
00109 
00110   nvtxs = graph->nvtxs;
00111   if (nvtxs == 0) {
00112     printf("\t***Cannot bisect a graph with 0 vertices!\n\t***You are trying to partition a graph into too many parts!\n");
00113     return 0;
00114   }
00115 
00116   /* Determine the weights of the partitions */
00117   tvwgt = idxsum(nvtxs, graph->vwgt);
00118   tpwgts2[0] = tvwgt*ssum(nparts/2, tpwgts);
00119   tpwgts2[1] = tvwgt-tpwgts2[0];
00120 
00121   MlevelEdgeBisection(ctrl, graph, tpwgts2, ubfactor);
00122   cut = graph->mincut;
00123 
00124   /* printf("%5d %5d %5d [%5d %f]\n", tpwgts2[0], tpwgts2[1], cut, tvwgt, ssum(nparts/2, tpwgts));*/
00125 
00126   label = graph->label;
00127   where = graph->where;
00128   for (i=0; i<nvtxs; i++)
00129     part[label[i]] = where[i] + fpart;
00130 
00131   if (nparts > 2) {
00132     SplitGraphPart(ctrl, graph, &lgraph, &rgraph);
00133     /* printf("%d %d\n", lgraph.nvtxs, rgraph.nvtxs); */
00134   }
00135 
00136 
00137   /* Free the memory of the top level graph */
00138   GKfree(&graph->gdata, &graph->rdata, &graph->label, LTERM);
00139 
00140   /* Scale the fractions in the tpwgts according to the true weight */
00141   wsum = ssum(nparts/2, tpwgts);
00142   sscale(nparts/2, 1.0/wsum, tpwgts);
00143   sscale(nparts-nparts/2, 1.0/(1.0-wsum), tpwgts+nparts/2);
00144   /*
00145   for (i=0; i<nparts; i++)
00146     printf("%5.3f ", tpwgts[i]);
00147   printf("[%5.3f]\n", wsum);
00148   */
00149 
00150   /* Do the recursive call */
00151   if (nparts > 3) {
00152     cut += MlevelRecursiveBisection(ctrl, &lgraph, nparts/2, part, tpwgts, ubfactor, fpart);
00153     cut += MlevelRecursiveBisection(ctrl, &rgraph, nparts-nparts/2, part, tpwgts+nparts/2, ubfactor, fpart+nparts/2);
00154   }
00155   else if (nparts == 3) {
00156     cut += MlevelRecursiveBisection(ctrl, &rgraph, nparts-nparts/2, part, tpwgts+nparts/2, ubfactor, fpart+nparts/2);
00157     GKfree(&lgraph.gdata, &lgraph.label, LTERM);
00158   }
00159 
00160   return cut;
00161 
00162 }
00163 
00164 
00165 /*************************************************************************
00166 * This function performs multilevel bisection
00167 **************************************************************************/
00168 void MlevelEdgeBisection(CtrlType *ctrl, GraphType *graph, int *tpwgts, floattype ubfactor)
00169 {
00170   GraphType *cgraph;
00171 
00172   cgraph = Coarsen2Way(ctrl, graph);
00173 
00174   Init2WayPartition(ctrl, cgraph, tpwgts, ubfactor);
00175 
00176   Refine2Way(ctrl, graph, cgraph, tpwgts, ubfactor);
00177 
00178 /*
00179   IsConnectedSubdomain(ctrl, graph, 0);
00180   IsConnectedSubdomain(ctrl, graph, 1);
00181 */
00182 }
00183 
00184 
00185 
00186 
00187 /*************************************************************************
00188 * This function takes a graph and a bisection and splits it into two graphs.
00189 **************************************************************************/
00190 void SplitGraphPart(CtrlType *ctrl, GraphType *graph, GraphType *lgraph, GraphType *rgraph)
00191 {
00192   int i, j, k, kk, l, istart, iend, mypart, nvtxs, ncon, snvtxs[2], snedges[2], sum;
00193   idxtype *xadj, *vwgt, *adjncy, *adjwgt, *adjwgtsum, *label, *where, *bndptr;
00194   idxtype *sxadj[2], *svwgt[2], *sadjncy[2], *sadjwgt[2], *sadjwgtsum[2], *slabel[2];
00195   idxtype *rename;
00196   idxtype *auxadjncy, *auxadjwgt;
00197   floattype *nvwgt, *snvwgt[2], *npwgts;
00198 
00199 
00200   IFSET(ctrl->dbglvl, DBG_TIME, starttimer(ctrl->SplitTmr));
00201 
00202   nvtxs = graph->nvtxs;
00203   ncon = graph->ncon;
00204   xadj = graph->xadj;
00205   vwgt = graph->vwgt;
00206   nvwgt = graph->nvwgt;
00207   adjncy = graph->adjncy;
00208   adjwgt = graph->adjwgt;
00209   adjwgtsum = graph->adjwgtsum;
00210   label = graph->label;
00211   where = graph->where;
00212   bndptr = graph->bndptr;
00213   npwgts = graph->npwgts;
00214 
00215   ASSERT(bndptr != NULL);
00216 
00217   rename = idxwspacemalloc(ctrl, nvtxs);
00218   
00219   snvtxs[0] = snvtxs[1] = snedges[0] = snedges[1] = 0;
00220   for (i=0; i<nvtxs; i++) {
00221     k = where[i];
00222     rename[i] = snvtxs[k]++;
00223     snedges[k] += xadj[i+1]-xadj[i];
00224   }
00225 
00226   SetUpSplitGraph(graph, lgraph, snvtxs[0], snedges[0]);
00227   sxadj[0] = lgraph->xadj;
00228   svwgt[0] = lgraph->vwgt;
00229   snvwgt[0] = lgraph->nvwgt;
00230   sadjwgtsum[0] = lgraph->adjwgtsum;
00231   sadjncy[0] = lgraph->adjncy;  
00232   sadjwgt[0] = lgraph->adjwgt; 
00233   slabel[0] = lgraph->label;
00234 
00235   SetUpSplitGraph(graph, rgraph, snvtxs[1], snedges[1]);
00236   sxadj[1] = rgraph->xadj;
00237   svwgt[1] = rgraph->vwgt;
00238   snvwgt[1] = rgraph->nvwgt;
00239   sadjwgtsum[1] = rgraph->adjwgtsum;
00240   sadjncy[1] = rgraph->adjncy;  
00241   sadjwgt[1] = rgraph->adjwgt; 
00242   slabel[1] = rgraph->label;
00243 
00244   snvtxs[0] = snvtxs[1] = snedges[0] = snedges[1] = 0;
00245   sxadj[0][0] = sxadj[1][0] = 0;
00246   for (i=0; i<nvtxs; i++) {
00247     mypart = where[i];
00248     sum = adjwgtsum[i];
00249 
00250     istart = xadj[i];
00251     iend = xadj[i+1];
00252     if (bndptr[i] == -1) { /* This is an interior vertex */
00253       auxadjncy = sadjncy[mypart] + snedges[mypart] - istart;
00254       auxadjwgt = sadjwgt[mypart] + snedges[mypart] - istart;
00255       for(j=istart; j<iend; j++) {
00256         auxadjncy[j] = adjncy[j];
00257         auxadjwgt[j] = adjwgt[j]; 
00258       }
00259       snedges[mypart] += iend-istart;
00260     }
00261     else {
00262       auxadjncy = sadjncy[mypart];
00263       auxadjwgt = sadjwgt[mypart];
00264       l = snedges[mypart];
00265       for (j=istart; j<iend; j++) {
00266         k = adjncy[j];
00267         if (where[k] == mypart) {
00268           auxadjncy[l] = k;
00269           auxadjwgt[l++] = adjwgt[j]; 
00270         }
00271         else {
00272           sum -= adjwgt[j];
00273         }
00274       }
00275       snedges[mypart] = l;
00276     }
00277 
00278     if (ncon == 1)
00279       svwgt[mypart][snvtxs[mypart]] = vwgt[i];
00280     else {
00281       for (kk=0; kk<ncon; kk++)
00282         snvwgt[mypart][snvtxs[mypart]*ncon+kk] = nvwgt[i*ncon+kk]/npwgts[mypart*ncon+kk];
00283     }
00284 
00285     sadjwgtsum[mypart][snvtxs[mypart]] = sum;
00286     slabel[mypart][snvtxs[mypart]] = label[i];
00287     sxadj[mypart][++snvtxs[mypart]] = snedges[mypart];
00288   }
00289 
00290   for (mypart=0; mypart<2; mypart++) {
00291     iend = sxadj[mypart][snvtxs[mypart]];
00292     auxadjncy = sadjncy[mypart];
00293     for (i=0; i<iend; i++) 
00294       auxadjncy[i] = rename[auxadjncy[i]];
00295   }
00296 
00297   lgraph->nedges = snedges[0];
00298   rgraph->nedges = snedges[1];
00299 
00300   IFSET(ctrl->dbglvl, DBG_TIME, stoptimer(ctrl->SplitTmr));
00301 
00302   idxwspacefree(ctrl, nvtxs);
00303 }
00304 
00305 
00306 /*************************************************************************
00307 * Setup the various arrays for the splitted graph
00308 **************************************************************************/
00309 void SetUpSplitGraph(GraphType *graph, GraphType *sgraph, int snvtxs, int snedges)
00310 {
00311   InitGraph(sgraph);
00312   sgraph->nvtxs = snvtxs;
00313   sgraph->nedges = snedges;
00314   sgraph->ncon = graph->ncon;
00315 
00316   /* Allocate memory for the splitted graph */
00317   if (graph->ncon == 1) {
00318     sgraph->gdata = idxmalloc(4*snvtxs+1 + 2*snedges, "SetUpSplitGraph: gdata");
00319 
00320     sgraph->xadj        = sgraph->gdata;
00321     sgraph->vwgt        = sgraph->gdata + snvtxs+1;
00322     sgraph->adjwgtsum   = sgraph->gdata + 2*snvtxs+1;
00323     sgraph->cmap        = sgraph->gdata + 3*snvtxs+1;
00324     sgraph->adjncy      = sgraph->gdata + 4*snvtxs+1;
00325     sgraph->adjwgt      = sgraph->gdata + 4*snvtxs+1 + snedges;
00326   }
00327   else {
00328     sgraph->gdata = idxmalloc(3*snvtxs+1 + 2*snedges, "SetUpSplitGraph: gdata");
00329 
00330     sgraph->xadj        = sgraph->gdata;
00331     sgraph->adjwgtsum   = sgraph->gdata + snvtxs+1;
00332     sgraph->cmap        = sgraph->gdata + 2*snvtxs+1;
00333     sgraph->adjncy      = sgraph->gdata + 3*snvtxs+1;
00334     sgraph->adjwgt      = sgraph->gdata + 3*snvtxs+1 + snedges;
00335 
00336     sgraph->nvwgt       = fmalloc(graph->ncon*snvtxs, "SetUpSplitGraph: nvwgt");
00337   }
00338 
00339   sgraph->label = idxmalloc(snvtxs, "SetUpSplitGraph: sgraph->label");
00340 }
00341
libs/ck-libs/parmetis/METISLib/pmetis.c
