/* * Copyright 1997, Regents of the University of Minnesota * * fm.c * * This file contains code that implements the edge-based FM refinement * * Started 7/23/97 * George * * $Id: fm.c 2501 2007-11-20 02:33:29Z benkirk $ */#include <metis.h>/************************************************************************** This function performs an edge-based FM refinement**************************************************************************/void FM_2WayEdgeRefine(CtrlType *ctrl, GraphType *graph, int *tpwgts, int npasses){  int i, ii, j, k, kwgt, nvtxs, nbnd, nswaps, from, to, pass, me, limit, tmp;  idxtype *xadj, *vwgt, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind, *pwgts;  idxtype *moved, *swaps, *perm;  PQueueType parts[2];  int higain, oldgain, mincut, mindiff, origdiff, initcut, newcut, mincutorder, avgvwgt;  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);  swaps = idxwspacemalloc(ctrl, nvtxs);  perm = idxwspacemalloc(ctrl, nvtxs);  limit = amin(amax(0.01*nvtxs, 15), 100);  avgvwgt = amin((pwgts[0]+pwgts[1])/20, 2*(pwgts[0]+pwgts[1])/nvtxs);  tmp = graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)];  PQueueInit(ctrl, &parts[0], nvtxs, tmp);  PQueueInit(ctrl, &parts[1], nvtxs, tmp);  IFSET(ctrl->dbglvl, DBG_REFINE,      printf("Partitions: [%6d %6d] T[%6d %6d], Nv-Nb[%6d %6d]. ICut: %6d\n",             pwgts[0], pwgts[1], tpwgts[0], tpwgts[1], graph->nvtxs, graph->nbnd, graph->mincut));  origdiff = abs(tpwgts[0]-pwgts[0]);  idxset(nvtxs, -1, moved);  for (pass=0; pass<npasses; pass++) { /* Do a number of passes */    PQueueReset(&parts[0]);    PQueueReset(&parts[1]);    mincutorder = -1;    newcut = mincut = initcut = graph->mincut;    mindiff = abs(tpwgts[0]-pwgts[0]);    ASSERT(ComputeCut(graph, where) == graph->mincut);    ASSERT(CheckBnd(graph));    /* Insert boundary nodes in the priority queues */    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);      PQueueInsert(&parts[where[bndind[i]]], bndind[i], ed[bndind[i]]-id[bndind[i]]);    }    for (nswaps=0; nswaps<nvtxs; nswaps++) {      from = (tpwgts[0]-pwgts[0] < tpwgts[1]-pwgts[1] ? 0 : 1);      to = (from+1)%2;      if ((higain = PQueueGetMax(&parts[from])) == -1)        break;      ASSERT(bndptr[higain] != -1);      newcut -= (ed[higain]-id[higain]);      INC_DEC(pwgts[to], pwgts[from], vwgt[higain]);      if ((newcut < mincut && abs(tpwgts[0]-pwgts[0]) <= origdiff+avgvwgt) ||           (newcut == mincut && abs(tpwgts[0]-pwgts[0]) < mindiff)) {        mincut = newcut;        mindiff = abs(tpwgts[0]-pwgts[0]);        mincutorder = nswaps;      }      else if (nswaps-mincutorder > limit) { /* We hit the limit, undo last move */        newcut += (ed[higain]-id[higain]);        INC_DEC(pwgts[from], pwgts[to], vwgt[higain]);        break;      }      where[higain] = to;      moved[higain] = nswaps;      swaps[nswaps] = higain;      IFSET(ctrl->dbglvl, DBG_MOVEINFO,         printf("Moved %6d from %d. [%3d %3d] %5d [%4d %4d]\n", higain, from, ed[higain]-id[higain], vwgt[higain], newcut, 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)  /* Remove it if in the queues */              PQueueDelete(&parts[where[k]], k, oldgain);          }          else { /* If it has not been moved, update its position in the queue */            if (moved[k] == -1)              PQueueUpdate(&parts[where[k]], 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)               PQueueInsert(&parts[where[k]], k, ed[k]-id[k]);          }        }      }    }    /****************************************************************    * Roll back computations    *****************************************************************/    for (i=0; i<nswaps; i++)      moved[swaps[i]] = -1;  /* reset moved array */    for (nswaps--; nswaps>mincutorder; nswaps--) {      higain = swaps[nswaps];      to = where[higain] = (where[higain]+1)%2;      SWAP(id[higain], ed[higain], tmp);      if (ed[higain] == 0 && bndptr[higain] != -1 && xadj[higain] < xadj[higain+1])        BNDDelete(nbnd, bndind,  bndptr, higain);      else if (ed[higain] > 0 && bndptr[higain] == -1)        BNDInsert(nbnd, bndind,  bndptr, higain);      INC_DEC(pwgts[to], pwgts[(to+1)%2], vwgt[higain]);      for (j=xadj[higain]; j<xadj[higain+1]; j++) {        k = adjncy[j];        kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]);        INC_DEC(id[k], ed[k], kwgt);        if (bndptr[k] != -1 && ed[k] == 0)          BNDDelete(nbnd, bndind, bndptr, k);        if (bndptr[k] == -1 && ed[k] > 0)          BNDInsert(nbnd, bndind, bndptr, k);      }    }    IFSET(ctrl->dbglvl, DBG_REFINE,       printf("\tMinimum cut: %6d at %5d, PWGTS: [%6d %6d], NBND: %6d\n", mincut, mincutorder, pwgts[0], pwgts[1], nbnd));    graph->mincut = mincut;    graph->nbnd = nbnd;    if (mincutorder == -1 || mincut == initcut)      break;  }  PQueueFree(ctrl, &parts[0]);  PQueueFree(ctrl, &parts[1]);  idxwspacefree(ctrl, nvtxs);  idxwspacefree(ctrl, nvtxs);  idxwspacefree(ctrl, nvtxs);}