mkmetis.c

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/*
 * Copyright 1997, Regents of the University of Minnesota
 *
 * mkmetis.c
 *
 * This file contains the top level routines for the multilevel k-way partitioning
 * algorithm KMETIS.
 *
 * Started 7/28/97
 * George
 *
 * $Id: mkmetis.c,v 1.2 1998/11/27 18:25:09 karypis Exp $
 *
 */
 
#include "metis.h"
 
 
 
/*************************************************************************
* This function is the entry point for KWMETIS
**************************************************************************/
void METIS_mCPartGraphKway(int *nvtxs, int *ncon, idxtype *xadj, idxtype *adjncy,
                          idxtype *vwgt, idxtype *adjwgt, int *wgtflag, int *numflag,
                          int *nparts, float *rubvec, int *options, int *edgecut,
                          idxtype *part)
{
  int i, j;
  GraphType graph;
  CtrlType ctrl;
 
  if (*numflag == 1)
    Change2CNumbering(*nvtxs, xadj, adjncy);
 
  SetUpGraph(&graph, OP_KMETIS, *nvtxs, *ncon, xadj, adjncy, vwgt, adjwgt, *wgtflag);
 
  if (options[0] == 0) {  /* Use the default parameters */
    ctrl.CType  = McKMETIS_CTYPE;
    ctrl.IType  = McKMETIS_ITYPE;
    ctrl.RType  = McKMETIS_RTYPE;
    ctrl.dbglvl = McKMETIS_DBGLVL;
  }
  else {
    ctrl.CType  = options[OPTION_CTYPE];
    ctrl.IType  = options[OPTION_ITYPE];
    ctrl.RType  = options[OPTION_RTYPE];
    ctrl.dbglvl = options[OPTION_DBGLVL];
  }
  ctrl.optype = OP_KMETIS;
  ctrl.CoarsenTo = amax((*nvtxs)/(20*log2_metis(*nparts)), 30*(*nparts));
 
  ctrl.nmaxvwgt = 1.5/(1.0*ctrl.CoarsenTo);
 
  InitRandom(-1);
 
  AllocateWorkSpace(&ctrl, &graph, *nparts);
 
  IFSET(ctrl.dbglvl, DBG_TIME, InitTimers(&ctrl));
  IFSET(ctrl.dbglvl, DBG_TIME, starttimer(ctrl.TotalTmr));
 
  *edgecut = MCMlevelKWayPartitioning(&ctrl, &graph, *nparts, part, rubvec);
 
  IFSET(ctrl.dbglvl, DBG_TIME, stoptimer(ctrl.TotalTmr));
  IFSET(ctrl.dbglvl, DBG_TIME, PrintTimers(&ctrl));
 
  FreeWorkSpace(&ctrl, &graph);
 
  if (*numflag == 1)
    Change2FNumbering(*nvtxs, xadj, adjncy, part);
}
 
 
/*************************************************************************
* This function takes a graph and produces a bisection of it
**************************************************************************/
int MCMlevelKWayPartitioning(CtrlType *ctrl, GraphType *graph, int nparts, idxtype *part,
      float *rubvec)
{
  int i, j, nvtxs;
  GraphType *cgraph;
  int options[10], edgecut;
 
  cgraph = MCCoarsen2Way(ctrl, graph);
 
  IFSET(ctrl->dbglvl, DBG_TIME, starttimer(ctrl->InitPartTmr));
  MocAllocateKWayPartitionMemory(ctrl, cgraph, nparts);
 
  options[0] = 1;
  options[OPTION_CTYPE] = MATCH_SBHEM_INFNORM;
  options[OPTION_ITYPE] = IPART_RANDOM;
  options[OPTION_RTYPE] = RTYPE_FM;
  options[OPTION_DBGLVL] = 0;
 
  /* Determine what you will use as the initial partitioner, based on tolerances */
  for (i=0; i<graph->ncon; i++) {
    if (rubvec[i] > 1.2)
      break;
  }
  if (i == graph->ncon)
    METIS_mCPartGraphRecursiveInternal(&cgraph->nvtxs, &cgraph->ncon,
          cgraph->xadj, cgraph->adjncy, cgraph->nvwgt, cgraph->adjwgt, &nparts,
          options, &edgecut, cgraph->where);
  else
    METIS_mCHPartGraphRecursiveInternal(&cgraph->nvtxs, &cgraph->ncon,
          cgraph->xadj, cgraph->adjncy, cgraph->nvwgt, cgraph->adjwgt, &nparts,
          rubvec, options, &edgecut, cgraph->where);
 
 
  IFSET(ctrl->dbglvl, DBG_TIME, stoptimer(ctrl->InitPartTmr));
  IFSET(ctrl->dbglvl, DBG_IPART, printf("Initial %d-way partitioning cut: %d\n", nparts, edgecut));
 
  IFSET(ctrl->dbglvl, DBG_KWAYPINFO, ComputePartitionInfo(cgraph, nparts, cgraph->where));
 
  MocRefineKWayHorizontal(ctrl, graph, cgraph, nparts, rubvec);
 
  idxcopy(graph->nvtxs, graph->where, part);
 
  GKfree((void **) &graph->nvwgt, (void **) &graph->npwgts, (void **) &graph->gdata, (void **) &graph->rdata, LTERM);
 
  return graph->mincut;
 
}