Example #1
0
/*************************************************************************
* This function performs k-way refinement
**************************************************************************/
void Greedy_KWayEdgeBalanceMConn(CtrlType *ctrl, GraphType *graph, int nparts, float *tpwgts, float ubfactor, int npasses)
{
  int i, ii, iii, j, jj, k, l, pass, nvtxs, nbnd, tvwgt, myndegrees, oldgain, gain, nmoves; 
  int from, me, to, oldcut, vwgt, maxndoms, nadd;
  idxtype *xadj, *adjncy, *adjwgt;
  idxtype *where, *pwgts, *perm, *bndptr, *bndind, *minwgt, *maxwgt, *moved, *itpwgts;
  idxtype *phtable, *pmat, *pmatptr, *ndoms;
  EDegreeType *myedegrees;
  RInfoType *myrinfo;
  PQueueType queue;

  nvtxs = graph->nvtxs;
  xadj = graph->xadj;
  adjncy = graph->adjncy;
  adjwgt = graph->adjwgt;

  bndind = graph->bndind;
  bndptr = graph->bndptr;

  where = graph->where;
  pwgts = graph->pwgts;
  
  pmat = ctrl->wspace.pmat;
  phtable = idxwspacemalloc(ctrl, nparts);
  ndoms = idxwspacemalloc(ctrl, nparts);

  ComputeSubDomainGraph(graph, nparts, pmat, ndoms);


  /* Setup the weight intervals of the various subdomains */
  minwgt =  idxwspacemalloc(ctrl, nparts);
  maxwgt = idxwspacemalloc(ctrl, nparts);
  itpwgts = idxwspacemalloc(ctrl, nparts);
  tvwgt = idxsum(nparts, pwgts);
  ASSERT(tvwgt == idxsum(nvtxs, graph->vwgt));

  for (i=0; i<nparts; i++) {
    itpwgts[i] = tpwgts[i]*tvwgt;
    maxwgt[i] = tpwgts[i]*tvwgt*ubfactor;
    minwgt[i] = tpwgts[i]*tvwgt*(1.0/ubfactor);
  }

  perm = idxwspacemalloc(ctrl, nvtxs);
  moved = idxwspacemalloc(ctrl, nvtxs);

  PQueueInit(ctrl, &queue, nvtxs, graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)]);

  IFSET(ctrl->dbglvl, DBG_REFINE,
     printf("Partitions: [%6d %6d]-[%6d %6d], Balance: %5.3f, Nv-Nb[%6d %6d]. Cut: %6d [B]\n",
             pwgts[idxamin(nparts, pwgts)], pwgts[idxamax(nparts, pwgts)], minwgt[0], maxwgt[0], 
             1.0*nparts*pwgts[idxamax(nparts, pwgts)]/tvwgt, graph->nvtxs, graph->nbnd,
             graph->mincut));

  for (pass=0; pass<npasses; pass++) {
    ASSERT(ComputeCut(graph, where) == graph->mincut);

    /* Check to see if things are out of balance, given the tolerance */
    for (i=0; i<nparts; i++) {
      if (pwgts[i] > maxwgt[i])
        break;
    }
    if (i == nparts) /* Things are balanced. Return right away */
      break;

    PQueueReset(&queue);
    idxset(nvtxs, -1, moved);

    oldcut = graph->mincut;
    nbnd = graph->nbnd;

    RandomPermute(nbnd, perm, 1);
    for (ii=0; ii<nbnd; ii++) {
      i = bndind[perm[ii]];
      PQueueInsert(&queue, i, graph->rinfo[i].ed - graph->rinfo[i].id);
      moved[i] = 2;
    }

    maxndoms = ndoms[idxamax(nparts, ndoms)];

    for (nmoves=0;;) {
      if ((i = PQueueGetMax(&queue)) == -1) 
        break;
      moved[i] = 1;

      myrinfo = graph->rinfo+i;
      from = where[i];
      vwgt = graph->vwgt[i];

      if (pwgts[from]-vwgt < minwgt[from]) 
        continue;   /* This cannot be moved! */

      myedegrees = myrinfo->edegrees;
      myndegrees = myrinfo->ndegrees;

      /* Determine the valid domains */
      for (j=0; j<myndegrees; j++) {
        to = myedegrees[j].pid;
        phtable[to] = 1;
        pmatptr = pmat + to*nparts;
        for (nadd=0, k=0; k<myndegrees; k++) {
          if (k == j)
            continue;

          l = myedegrees[k].pid;
          if (pmatptr[l] == 0) {
            if (ndoms[l] > maxndoms-1) {
              phtable[to] = 0;
              nadd = maxndoms;
              break;
            }
            nadd++;
          }
        }
        if (ndoms[to]+nadd > maxndoms)
          phtable[to] = 0;
      }

      for (k=0; k<myndegrees; k++) {
        to = myedegrees[k].pid;
        if (!phtable[to])
          continue;
        if (pwgts[to]+vwgt <= maxwgt[to] || itpwgts[from]*(pwgts[to]+vwgt) <= itpwgts[to]*pwgts[from]) 
          break;
      }
      if (k == myndegrees)
        continue;  /* break out if you did not find a candidate */

      for (j=k+1; j<myndegrees; j++) {
        to = myedegrees[j].pid;
        if (!phtable[to])
          continue;
        if (itpwgts[myedegrees[k].pid]*pwgts[to] < itpwgts[to]*pwgts[myedegrees[k].pid]) 
          k = j;
      }

      to = myedegrees[k].pid;

      if (pwgts[from] < maxwgt[from] && pwgts[to] > minwgt[to] && myedegrees[k].ed-myrinfo->id < 0) 
        continue;

      /*=====================================================================
      * If we got here, we can now move the vertex from 'from' to 'to' 
      *======================================================================*/
      graph->mincut -= myedegrees[k].ed-myrinfo->id;

      IFSET(ctrl->dbglvl, DBG_MOVEINFO, printf("\t\tMoving %6d to %3d. Gain: %4d. Cut: %6d\n", i, to, myedegrees[k].ed-myrinfo->id, graph->mincut));

      /* Update pmat to reflect the move of 'i' */
      pmat[from*nparts+to] += (myrinfo->id-myedegrees[k].ed);
      pmat[to*nparts+from] += (myrinfo->id-myedegrees[k].ed);
      if (pmat[from*nparts+to] == 0) {
        ndoms[from]--;
        if (ndoms[from]+1 == maxndoms)
          maxndoms = ndoms[idxamax(nparts, ndoms)];
      }
      if (pmat[to*nparts+from] == 0) {
        ndoms[to]--;
        if (ndoms[to]+1 == maxndoms)
          maxndoms = ndoms[idxamax(nparts, ndoms)];
      }


      /* Update where, weight, and ID/ED information of the vertex you moved */
      where[i] = to;
      INC_DEC(pwgts[to], pwgts[from], vwgt);
      myrinfo->ed += myrinfo->id-myedegrees[k].ed;
      SWAP(myrinfo->id, myedegrees[k].ed, j);
      if (myedegrees[k].ed == 0) 
        myedegrees[k] = myedegrees[--myrinfo->ndegrees];
      else
        myedegrees[k].pid = from;

      if (myrinfo->ed == 0)
        BNDDelete(nbnd, bndind, bndptr, i);

      /* Update the degrees of adjacent vertices */
      for (j=xadj[i]; j<xadj[i+1]; j++) {
        ii = adjncy[j];
        me = where[ii];

        myrinfo = graph->rinfo+ii;
        if (myrinfo->edegrees == NULL) {
          myrinfo->edegrees = ctrl->wspace.edegrees+ctrl->wspace.cdegree;
          ctrl->wspace.cdegree += xadj[ii+1]-xadj[ii];
        }
        myedegrees = myrinfo->edegrees;

        ASSERT(CheckRInfo(myrinfo));

        oldgain = (myrinfo->ed-myrinfo->id);

        if (me == from) {
          INC_DEC(myrinfo->ed, myrinfo->id, adjwgt[j]);

          if (myrinfo->ed > 0 && bndptr[ii] == -1)
            BNDInsert(nbnd, bndind, bndptr, ii);
        }
        else if (me == to) {
          INC_DEC(myrinfo->id, myrinfo->ed, adjwgt[j]);

          if (myrinfo->ed == 0 && bndptr[ii] != -1)
            BNDDelete(nbnd, bndind, bndptr, ii);
        }

        /* Remove contribution from the .ed of 'from' */
        if (me != from) {
          for (k=0; k<myrinfo->ndegrees; k++) {
            if (myedegrees[k].pid == from) {
              if (myedegrees[k].ed == adjwgt[j])
                myedegrees[k] = myedegrees[--myrinfo->ndegrees];
              else
                myedegrees[k].ed -= adjwgt[j];
              break;
            }
          }
        }

        /* Add contribution to the .ed of 'to' */
        if (me != to) {
          for (k=0; k<myrinfo->ndegrees; k++) {
            if (myedegrees[k].pid == to) {
              myedegrees[k].ed += adjwgt[j];
              break;
            }
          }
          if (k == myrinfo->ndegrees) {
            myedegrees[myrinfo->ndegrees].pid = to;
            myedegrees[myrinfo->ndegrees++].ed = adjwgt[j];
          }
        }

        /* Update pmat to reflect the move of 'i' for domains other than 'from' and 'to' */
        if (me != from && me != to) {
          pmat[me*nparts+from] -= adjwgt[j];
          pmat[from*nparts+me] -= adjwgt[j];
          if (pmat[me*nparts+from] == 0) {
            ndoms[me]--;
            if (ndoms[me]+1 == maxndoms)
              maxndoms = ndoms[idxamax(nparts, ndoms)];
          }
          if (pmat[from*nparts+me] == 0) {
            ndoms[from]--;
            if (ndoms[from]+1 == maxndoms)
              maxndoms = ndoms[idxamax(nparts, ndoms)];
          }

          if (pmat[me*nparts+to] == 0) {
            ndoms[me]++;
            if (ndoms[me] > maxndoms) {
              printf("You just increased the maxndoms: %d %d\n", ndoms[me], maxndoms);
              maxndoms = ndoms[me];
            }
          }
          if (pmat[to*nparts+me] == 0) {
            ndoms[to]++;
            if (ndoms[to] > maxndoms) {
              printf("You just increased the maxndoms: %d %d\n", ndoms[to], maxndoms);
              maxndoms = ndoms[to];
            }
          }
          pmat[me*nparts+to] += adjwgt[j];
          pmat[to*nparts+me] += adjwgt[j];
        }

        /* Update the queue */
        if (me == to || me == from) { 
          gain = myrinfo->ed-myrinfo->id;
          if (moved[ii] == 2) {
            if (myrinfo->ed > 0)
              PQueueUpdate(&queue, ii, oldgain, gain);
            else {
              PQueueDelete(&queue, ii, oldgain);
              moved[ii] = -1;
            }
          }
          else if (moved[ii] == -1 && myrinfo->ed > 0) {
            PQueueInsert(&queue, ii, gain);
            moved[ii] = 2;
          }
        } 

        ASSERT(myrinfo->ndegrees <= xadj[ii+1]-xadj[ii]);
        ASSERT(CheckRInfo(myrinfo));
      }
      nmoves++;
    }

    graph->nbnd = nbnd;

    IFSET(ctrl->dbglvl, DBG_REFINE,
       printf("\t[%6d %6d], Balance: %5.3f, Nb: %6d. Nmoves: %5d, Cut: %6d, %d\n",
               pwgts[idxamin(nparts, pwgts)], pwgts[idxamax(nparts, pwgts)],
               1.0*nparts*pwgts[idxamax(nparts, pwgts)]/tvwgt, graph->nbnd, nmoves, graph->mincut,idxsum(nparts, ndoms)));
  }

  PQueueFree(ctrl, &queue);

  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nvtxs);
  idxwspacefree(ctrl, nvtxs);

}
Example #2
0
/*************************************************************************
* This function performs k-way refinement
**************************************************************************/
void Random_KWayEdgeRefineMConn(CtrlType *ctrl, GraphType *graph, int nparts, float *tpwgts, float ubfactor, int npasses, int ffactor)
{
  int i, ii, iii, j, jj, k, l, pass, nvtxs, nmoves, nbnd, tvwgt, myndegrees; 
  int from, me, to, oldcut, vwgt, gain;
  int maxndoms, nadd;
  idxtype *xadj, *adjncy, *adjwgt;
  idxtype *where, *pwgts, *perm, *bndptr, *bndind, *minwgt, *maxwgt, *itpwgts;
  idxtype *phtable, *pmat, *pmatptr, *ndoms;
  EDegreeType *myedegrees;
  RInfoType *myrinfo;

  nvtxs = graph->nvtxs;
  xadj = graph->xadj;
  adjncy = graph->adjncy;
  adjwgt = graph->adjwgt;

  bndptr = graph->bndptr;
  bndind = graph->bndind;

  where = graph->where;
  pwgts = graph->pwgts;

  pmat = ctrl->wspace.pmat;
  phtable = idxwspacemalloc(ctrl, nparts);
  ndoms = idxwspacemalloc(ctrl, nparts);

  ComputeSubDomainGraph(graph, nparts, pmat, ndoms);

  /* Setup the weight intervals of the various subdomains */
  minwgt =  idxwspacemalloc(ctrl, nparts);
  maxwgt = idxwspacemalloc(ctrl, nparts);
  itpwgts = idxwspacemalloc(ctrl, nparts);
  tvwgt = idxsum(nparts, pwgts);
  ASSERT(tvwgt == idxsum(nvtxs, graph->vwgt));

  for (i=0; i<nparts; i++) {
    itpwgts[i] = tpwgts[i]*tvwgt;
    maxwgt[i] = tpwgts[i]*tvwgt*ubfactor;
    minwgt[i] = tpwgts[i]*tvwgt*(1.0/ubfactor);
  }

  perm = idxwspacemalloc(ctrl, nvtxs);

  IFSET(ctrl->dbglvl, DBG_REFINE,
     printf("Partitions: [%6d %6d]-[%6d %6d], Balance: %5.3f, Nv-Nb[%6d %6d]. Cut: %6d\n",
             pwgts[idxamin(nparts, pwgts)], pwgts[idxamax(nparts, pwgts)], minwgt[0], maxwgt[0], 
             1.0*nparts*pwgts[idxamax(nparts, pwgts)]/tvwgt, graph->nvtxs, graph->nbnd,
             graph->mincut));

  for (pass=0; pass<npasses; pass++) {
    ASSERT(ComputeCut(graph, where) == graph->mincut);

    maxndoms = ndoms[idxamax(nparts, ndoms)];

    oldcut = graph->mincut;
    nbnd = graph->nbnd;

    RandomPermute(nbnd, perm, 1);
    for (nmoves=iii=0; iii<graph->nbnd; iii++) {
      ii = perm[iii];
      if (ii >= nbnd)
        continue;
      i = bndind[ii];

      myrinfo = graph->rinfo+i;

      if (myrinfo->ed >= myrinfo->id) { /* Total ED is too high */
        from = where[i];
        vwgt = graph->vwgt[i];

        if (myrinfo->id > 0 && pwgts[from]-vwgt < minwgt[from]) 
          continue;   /* This cannot be moved! */

        myedegrees = myrinfo->edegrees;
        myndegrees = myrinfo->ndegrees;

        /* Determine the valid domains */
        for (j=0; j<myndegrees; j++) {
          to = myedegrees[j].pid;
          phtable[to] = 1;
          pmatptr = pmat + to*nparts;
          for (nadd=0, k=0; k<myndegrees; k++) {
            if (k == j)
              continue;

            l = myedegrees[k].pid;
            if (pmatptr[l] == 0) {
              if (ndoms[l] > maxndoms-1) {
                phtable[to] = 0;
                nadd = maxndoms;
                break;
              }
              nadd++;
            }
          }
          if (ndoms[to]+nadd > maxndoms)
            phtable[to] = 0;
          if (nadd == 0)
            phtable[to] = 2;
        }

        /* Find the first valid move */
        j = myrinfo->id;
        for (k=0; k<myndegrees; k++) {
          to = myedegrees[k].pid;
          if (!phtable[to])
            continue;
          gain = myedegrees[k].ed-j; /* j = myrinfo->id. Allow good nodes to move */ 
          if (pwgts[to]+vwgt <= maxwgt[to]+ffactor*gain && gain >= 0)  
            break;
        }
        if (k == myndegrees)
          continue;  /* break out if you did not find a candidate */

        for (j=k+1; j<myndegrees; j++) {
          to = myedegrees[j].pid;
          if (!phtable[to])
            continue;
          if ((myedegrees[j].ed > myedegrees[k].ed && pwgts[to]+vwgt <= maxwgt[to]) ||
              (myedegrees[j].ed == myedegrees[k].ed && 
               itpwgts[myedegrees[k].pid]*pwgts[to] < itpwgts[to]*pwgts[myedegrees[k].pid]))
            k = j;
        }

        to = myedegrees[k].pid;

        j = 0;
        if (myedegrees[k].ed-myrinfo->id > 0)
          j = 1;
        else if (myedegrees[k].ed-myrinfo->id == 0) {
          if (/*(iii&7) == 0  ||*/ phtable[myedegrees[k].pid] == 2 || pwgts[from] >= maxwgt[from] || itpwgts[from]*(pwgts[to]+vwgt) < itpwgts[to]*pwgts[from])
            j = 1;
        }
        if (j == 0)
          continue;
          
        /*=====================================================================
        * If we got here, we can now move the vertex from 'from' to 'to' 
        *======================================================================*/
        graph->mincut -= myedegrees[k].ed-myrinfo->id;

        IFSET(ctrl->dbglvl, DBG_MOVEINFO, printf("\t\tMoving %6d to %3d. Gain: %4d. Cut: %6d\n", i, to, myedegrees[k].ed-myrinfo->id, graph->mincut));

        /* Update pmat to reflect the move of 'i' */
        pmat[from*nparts+to] += (myrinfo->id-myedegrees[k].ed);
        pmat[to*nparts+from] += (myrinfo->id-myedegrees[k].ed);
        if (pmat[from*nparts+to] == 0) {
          ndoms[from]--;
          if (ndoms[from]+1 == maxndoms)
            maxndoms = ndoms[idxamax(nparts, ndoms)];
        }
        if (pmat[to*nparts+from] == 0) {
          ndoms[to]--;
          if (ndoms[to]+1 == maxndoms)
            maxndoms = ndoms[idxamax(nparts, ndoms)];
        }

        /* Update where, weight, and ID/ED information of the vertex you moved */
        where[i] = to;
        INC_DEC(pwgts[to], pwgts[from], vwgt);
        myrinfo->ed += myrinfo->id-myedegrees[k].ed;
        SWAP(myrinfo->id, myedegrees[k].ed, j);
        if (myedegrees[k].ed == 0) 
          myedegrees[k] = myedegrees[--myrinfo->ndegrees];
        else
          myedegrees[k].pid = from;

        if (myrinfo->ed-myrinfo->id < 0)
          BNDDelete(nbnd, bndind, bndptr, i);

        /* Update the degrees of adjacent vertices */
        for (j=xadj[i]; j<xadj[i+1]; j++) {
          ii = adjncy[j];
          me = where[ii];

          myrinfo = graph->rinfo+ii;
          if (myrinfo->edegrees == NULL) {
            myrinfo->edegrees = ctrl->wspace.edegrees+ctrl->wspace.cdegree;
            ctrl->wspace.cdegree += xadj[ii+1]-xadj[ii];
          }
          myedegrees = myrinfo->edegrees;

          ASSERT(CheckRInfo(myrinfo));

          if (me == from) {
            INC_DEC(myrinfo->ed, myrinfo->id, adjwgt[j]);

            if (myrinfo->ed-myrinfo->id >= 0 && bndptr[ii] == -1)
              BNDInsert(nbnd, bndind, bndptr, ii);
          }
          else if (me == to) {
            INC_DEC(myrinfo->id, myrinfo->ed, adjwgt[j]);

            if (myrinfo->ed-myrinfo->id < 0 && bndptr[ii] != -1)
              BNDDelete(nbnd, bndind, bndptr, ii);
          }

          /* Remove contribution from the .ed of 'from' */
          if (me != from) {
            for (k=0; k<myrinfo->ndegrees; k++) {
              if (myedegrees[k].pid == from) {
                if (myedegrees[k].ed == adjwgt[j])
                  myedegrees[k] = myedegrees[--myrinfo->ndegrees];
                else
                  myedegrees[k].ed -= adjwgt[j];
                break;
              }
            }
          }

          /* Add contribution to the .ed of 'to' */
          if (me != to) {
            for (k=0; k<myrinfo->ndegrees; k++) {
              if (myedegrees[k].pid == to) {
                myedegrees[k].ed += adjwgt[j];
                break;
              }
            }
            if (k == myrinfo->ndegrees) {
              myedegrees[myrinfo->ndegrees].pid = to;
              myedegrees[myrinfo->ndegrees++].ed = adjwgt[j];
            }
          }

          /* Update pmat to reflect the move of 'i' for domains other than 'from' and 'to' */
          if (me != from && me != to) {
            pmat[me*nparts+from] -= adjwgt[j];
            pmat[from*nparts+me] -= adjwgt[j];
            if (pmat[me*nparts+from] == 0) {
              ndoms[me]--;
              if (ndoms[me]+1 == maxndoms)
                maxndoms = ndoms[idxamax(nparts, ndoms)];
            }
            if (pmat[from*nparts+me] == 0) {
              ndoms[from]--;
              if (ndoms[from]+1 == maxndoms)
                maxndoms = ndoms[idxamax(nparts, ndoms)];
            }

            if (pmat[me*nparts+to] == 0) {
              ndoms[me]++;
              if (ndoms[me] > maxndoms) {
                printf("You just increased the maxndoms: %d %d\n", ndoms[me], maxndoms);
                maxndoms = ndoms[me];
              }
            }
            if (pmat[to*nparts+me] == 0) {
              ndoms[to]++;
              if (ndoms[to] > maxndoms) {
                printf("You just increased the maxndoms: %d %d\n", ndoms[to], maxndoms);
                maxndoms = ndoms[to];
              }
            }
            pmat[me*nparts+to] += adjwgt[j];
            pmat[to*nparts+me] += adjwgt[j];
          }

          ASSERT(myrinfo->ndegrees <= xadj[ii+1]-xadj[ii]);
          ASSERT(CheckRInfo(myrinfo));

        }
        nmoves++;
      }
    }

    graph->nbnd = nbnd;

    IFSET(ctrl->dbglvl, DBG_REFINE,
       printf("\t[%6d %6d], Balance: %5.3f, Nb: %6d. Nmoves: %5d, Cut: %5d, Vol: %5d, %d\n",
               pwgts[idxamin(nparts, pwgts)], pwgts[idxamax(nparts, pwgts)],
               1.0*nparts*pwgts[idxamax(nparts, pwgts)]/tvwgt, graph->nbnd, nmoves, 
               graph->mincut, ComputeVolume(graph, where), idxsum(nparts, ndoms)));

    if (graph->mincut == oldcut)
      break;
  }

  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nparts);
  idxwspacefree(ctrl, nvtxs);
}
Example #3
0
/*************************************************************************
* This function performs k-way refinement
**************************************************************************/
void Greedy_KWayEdgeRefine(CtrlType *ctrl, GraphType *graph, int nparts, float *tpwgts, float ubfactor, int npasses)
{
    int i, ii, iii, j, jj, k, l, pass, nvtxs, nbnd, tvwgt, myndegrees, oldgain, gain;
    int from, me, to, oldcut, vwgt;
    idxtype *xadj, *adjncy, *adjwgt;
    idxtype *where, *pwgts, *perm, *bndptr, *bndind, *minwgt, *maxwgt, *moved, *itpwgts;
    EDegreeType *myedegrees;
    RInfoType *myrinfo;
    PQueueType queue;

    nvtxs = graph->nvtxs;
    xadj = graph->xadj;
    adjncy = graph->adjncy;
    adjwgt = graph->adjwgt;

    bndind = graph->bndind;
    bndptr = graph->bndptr;

    where = graph->where;
    pwgts = graph->pwgts;

    /* Setup the weight intervals of the various subdomains */
    minwgt =  idxwspacemalloc(ctrl, nparts);
    maxwgt = idxwspacemalloc(ctrl, nparts);
    itpwgts = idxwspacemalloc(ctrl, nparts);
    tvwgt = idxsum(nparts, pwgts);
    ASSERT(tvwgt == idxsum(nvtxs, graph->vwgt));

    for (i=0; i<nparts; i++) {
        itpwgts[i] = tpwgts[i]*tvwgt;
        maxwgt[i] = tpwgts[i]*tvwgt*ubfactor;
        minwgt[i] = tpwgts[i]*tvwgt*(1.0/ubfactor);
    }

    perm = idxwspacemalloc(ctrl, nvtxs);
    moved = idxwspacemalloc(ctrl, nvtxs);

    PQueueInit(ctrl, &queue, nvtxs, graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)]);

    IFSET(ctrl->dbglvl, DBG_REFINE,
          printf("Partitions: [%6d %6d]-[%6d %6d], Balance: %5.3f, Nv-Nb[%6d %6d]. Cut: %6d\n",
                 pwgts[idxamin(nparts, pwgts)], pwgts[idxamax(nparts, pwgts)], minwgt[0], maxwgt[0],
                 1.0*nparts*pwgts[idxamax(nparts, pwgts)]/tvwgt, graph->nvtxs, graph->nbnd,
                 graph->mincut));

    for (pass=0; pass<npasses; pass++) {
        ASSERT(ComputeCut(graph, where) == graph->mincut);

        PQueueReset(&queue);
        idxset(nvtxs, -1, moved);

        oldcut = graph->mincut;
        nbnd = graph->nbnd;

        RandomPermute(nbnd, perm, 1);
        for (ii=0; ii<nbnd; ii++) {
            i = bndind[perm[ii]];
            PQueueInsert(&queue, i, graph->rinfo[i].ed - graph->rinfo[i].id);
            moved[i] = 2;
        }

        for (iii=0;; iii++) {
            if ((i = PQueueGetMax(&queue)) == -1)
                break;
            moved[i] = 1;

            myrinfo = graph->rinfo+i;
            from = where[i];
            vwgt = graph->vwgt[i];

            if (pwgts[from]-vwgt < minwgt[from])
                continue;   /* This cannot be moved! */

            myedegrees = myrinfo->edegrees;
            myndegrees = myrinfo->ndegrees;

            j = myrinfo->id;
            for (k=0; k<myndegrees; k++) {
                to = myedegrees[k].pid;
                gain = myedegrees[k].ed-j; /* j = myrinfo->id. Allow good nodes to move */
                if (pwgts[to]+vwgt <= maxwgt[to]+gain && gain >= 0)
                    break;
            }
            if (k == myndegrees)
                continue;  /* break out if you did not find a candidate */

            for (j=k+1; j<myndegrees; j++) {
                to = myedegrees[j].pid;
                if ((myedegrees[j].ed > myedegrees[k].ed && pwgts[to]+vwgt <= maxwgt[to]) ||
                        (myedegrees[j].ed == myedegrees[k].ed &&
                         itpwgts[myedegrees[k].pid]*pwgts[to] < itpwgts[to]*pwgts[myedegrees[k].pid]))
                    k = j;
            }

            to = myedegrees[k].pid;

            j = 0;
            if (myedegrees[k].ed-myrinfo->id > 0)
                j = 1;
            else if (myedegrees[k].ed-myrinfo->id == 0) {
                if ((iii&7) == 0 || pwgts[from] >= maxwgt[from] || itpwgts[from]*(pwgts[to]+vwgt) < itpwgts[to]*pwgts[from])
                    j = 1;
            }
            if (j == 0)
                continue;

            /*=====================================================================
            * If we got here, we can now move the vertex from 'from' to 'to'
            *======================================================================*/
            graph->mincut -= myedegrees[k].ed-myrinfo->id;

            IFSET(ctrl->dbglvl, DBG_MOVEINFO, printf("\t\tMoving %6d to %3d. Gain: %4d. Cut: %6d\n", i, to, myedegrees[k].ed-myrinfo->id, graph->mincut));

            /* Update where, weight, and ID/ED information of the vertex you moved */
            where[i] = to;
            INC_DEC(pwgts[to], pwgts[from], vwgt);
            myrinfo->ed += myrinfo->id-myedegrees[k].ed;
            SWAP(myrinfo->id, myedegrees[k].ed, j);
            if (myedegrees[k].ed == 0)
                myedegrees[k] = myedegrees[--myrinfo->ndegrees];
            else
                myedegrees[k].pid = from;

            if (myrinfo->ed < myrinfo->id)
                BNDDelete(nbnd, bndind, bndptr, i);

            /* Update the degrees of adjacent vertices */
            for (j=xadj[i]; j<xadj[i+1]; j++) {
                ii = adjncy[j];
                me = where[ii];

                myrinfo = graph->rinfo+ii;
                if (myrinfo->edegrees == NULL) {
                    myrinfo->edegrees = ctrl->wspace.edegrees+ctrl->wspace.cdegree;
                    ctrl->wspace.cdegree += xadj[ii+1]-xadj[ii];
                }
                myedegrees = myrinfo->edegrees;

                ASSERT(CheckRInfo(myrinfo));

                oldgain = (myrinfo->ed-myrinfo->id);

                if (me == from) {
                    INC_DEC(myrinfo->ed, myrinfo->id, adjwgt[j]);

                    if (myrinfo->ed-myrinfo->id >= 0 && bndptr[ii] == -1)
                        BNDInsert(nbnd, bndind, bndptr, ii);
                }
                else if (me == to) {
                    INC_DEC(myrinfo->id, myrinfo->ed, adjwgt[j]);

                    if (myrinfo->ed-myrinfo->id < 0 && bndptr[ii] != -1)
                        BNDDelete(nbnd, bndind, bndptr, ii);
                }

                /* Remove contribution from the .ed of 'from' */
                if (me != from) {
                    for (k=0; k<myrinfo->ndegrees; k++) {
                        if (myedegrees[k].pid == from) {
                            if (myedegrees[k].ed == adjwgt[j])
                                myedegrees[k] = myedegrees[--myrinfo->ndegrees];
                            else
                                myedegrees[k].ed -= adjwgt[j];
                            break;
                        }
                    }
                }

                /* Add contribution to the .ed of 'to' */
                if (me != to) {
                    for (k=0; k<myrinfo->ndegrees; k++) {
                        if (myedegrees[k].pid == to) {
                            myedegrees[k].ed += adjwgt[j];
                            break;
                        }
                    }
                    if (k == myrinfo->ndegrees) {
                        myedegrees[myrinfo->ndegrees].pid = to;
                        myedegrees[myrinfo->ndegrees++].ed = adjwgt[j];
                    }
                }

                /* Update the queue */
                if (me == to || me == from) {
                    gain = myrinfo->ed-myrinfo->id;
                    if (moved[ii] == 2) {
                        if (gain >= 0)
                            PQueueUpdate(&queue, ii, oldgain, gain);
                        else {
                            PQueueDelete(&queue, ii, oldgain);
                            moved[ii] = -1;
                        }
                    }
                    else if (moved[ii] == -1 && gain >= 0) {
                        PQueueInsert(&queue, ii, gain);
                        moved[ii] = 2;
                    }
                }

                ASSERT(myrinfo->ndegrees <= xadj[ii+1]-xadj[ii]);
                ASSERT(CheckRInfo(myrinfo));

            }
        }

        graph->nbnd = nbnd;

        IFSET(ctrl->dbglvl, DBG_REFINE,
              printf("\t[%6d %6d], Balance: %5.3f, Nb: %6d. Cut: %6d\n",
                     pwgts[idxamin(nparts, pwgts)], pwgts[idxamax(nparts, pwgts)],
                     1.0*nparts*pwgts[idxamax(nparts, pwgts)]/tvwgt, graph->nbnd, graph->mincut));

        if (graph->mincut == oldcut)
            break;
    }

    PQueueFree(ctrl, &queue);

    idxwspacefree(ctrl, nparts);
    idxwspacefree(ctrl, nparts);
    idxwspacefree(ctrl, nparts);
    idxwspacefree(ctrl, nvtxs);
    idxwspacefree(ctrl, nvtxs);

}
Example #4
0
/*************************************************************************
* This function computes cuts and balance information
**************************************************************************/
void ComputePartitionInfo(GraphType *graph, int nparts, idxtype *where)
{
  int i, j, /*k,*/ nvtxs, ncon, mustfree=0;
  idxtype *xadj, *adjncy, *vwgt, *adjwgt, *kpwgts, *tmpptr;
  idxtype *padjncy, *padjwgt, *padjcut;

  nvtxs = graph->nvtxs;
  ncon = graph->ncon;
  xadj = graph->xadj;
  adjncy = graph->adjncy;
  vwgt = graph->vwgt;
  adjwgt = graph->adjwgt;

  if (vwgt == NULL) {
    vwgt = graph->vwgt = idxsmalloc(nvtxs, 1, "vwgt");
    mustfree = 1;
  }
  if (adjwgt == NULL) {
    adjwgt = graph->adjwgt = idxsmalloc(xadj[nvtxs], 1, "adjwgt");
    mustfree += 2;
  }

  printf("%d-way Cut: %5d, Vol: %5d, ", nparts, ComputeCut(graph, where), ComputeVolume(graph, where));

  /* Compute balance information */
  kpwgts = idxsmalloc(ncon*nparts, 0, "ComputePartitionInfo: kpwgts");

  for (i=0; i<nvtxs; i++) {
    for (j=0; j<ncon; j++) 
      kpwgts[where[i]*ncon+j] += vwgt[i*ncon+j];
  }

  if (ncon == 1) {
    printf("\tBalance: %5.3f out of %5.3f\n", 
            1.0*nparts*kpwgts[idxamax(nparts, kpwgts)]/(1.0*idxsum(nparts, kpwgts)),
            1.0*nparts*vwgt[idxamax(nvtxs, vwgt)]/(1.0*idxsum(nparts, kpwgts)));
  }
  else {
    printf("\tBalance:");
    for (j=0; j<ncon; j++) 
      printf(" (%5.3f out of %5.3f)", 
            1.0*nparts*kpwgts[ncon*idxamax_strd(nparts, kpwgts+j, ncon)+j]/(1.0*idxsum_strd(nparts, kpwgts+j, ncon)),
            1.0*nparts*vwgt[ncon*idxamax_strd(nvtxs, vwgt+j, ncon)+j]/(1.0*idxsum_strd(nparts, kpwgts+j, ncon)));
    printf("\n");
  }


  /* Compute p-adjncy information */
  padjncy = idxsmalloc(nparts*nparts, 0, "ComputePartitionInfo: padjncy");
  padjwgt = idxsmalloc(nparts*nparts, 0, "ComputePartitionInfo: padjwgt");
  padjcut = idxsmalloc(nparts*nparts, 0, "ComputePartitionInfo: padjwgt");

  idxset(nparts, 0, kpwgts);
  for (i=0; i<nvtxs; i++) {
    for (j=xadj[i]; j<xadj[i+1]; j++) {
      if (where[i] != where[adjncy[j]]) {
        padjncy[where[i]*nparts+where[adjncy[j]]] = 1;
        padjcut[where[i]*nparts+where[adjncy[j]]] += adjwgt[j];
        if (kpwgts[where[adjncy[j]]] == 0) {
          padjwgt[where[i]*nparts+where[adjncy[j]]]++;
          kpwgts[where[adjncy[j]]] = 1;
        }
      }
    }
    for (j=xadj[i]; j<xadj[i+1]; j++) 
      kpwgts[where[adjncy[j]]] = 0;
  }

  for (i=0; i<nparts; i++)
    kpwgts[i] = idxsum(nparts, padjncy+i*nparts);
  printf("Min/Max/Avg/Bal # of adjacent     subdomains: %5d %5d %5.2f %7.3f\n",
    kpwgts[idxamin(nparts, kpwgts)], kpwgts[idxamax(nparts, kpwgts)], 
    1.0*idxsum(nparts, kpwgts)/(1.0*nparts), 
    1.0*nparts*kpwgts[idxamax(nparts, kpwgts)]/(1.0*idxsum(nparts, kpwgts)));

  for (i=0; i<nparts; i++)
    kpwgts[i] = idxsum(nparts, padjcut+i*nparts);
  printf("Min/Max/Avg/Bal # of adjacent subdomain cuts: %5d %5d %5d %7.3f\n",
    kpwgts[idxamin(nparts, kpwgts)], kpwgts[idxamax(nparts, kpwgts)], idxsum(nparts, kpwgts)/nparts, 
    1.0*nparts*kpwgts[idxamax(nparts, kpwgts)]/(1.0*idxsum(nparts, kpwgts)));

  for (i=0; i<nparts; i++)
    kpwgts[i] = idxsum(nparts, padjwgt+i*nparts);
  printf("Min/Max/Avg/Bal/Frac # of interface    nodes: %5d %5d %5d %7.3f %7.3f\n",
    kpwgts[idxamin(nparts, kpwgts)], kpwgts[idxamax(nparts, kpwgts)], idxsum(nparts, kpwgts)/nparts, 
    1.0*nparts*kpwgts[idxamax(nparts, kpwgts)]/(1.0*idxsum(nparts, kpwgts)), 1.0*idxsum(nparts, kpwgts)/(1.0*nvtxs));

  tmpptr = graph->where;
  graph->where = where;
  for (i=0; i<nparts; i++)
    IsConnectedSubdomain(NULL, graph, i, 1);
  graph->where = tmpptr;

  if (mustfree == 1 || mustfree == 3) {
    free(vwgt);
    graph->vwgt = NULL;
  }
  if (mustfree == 2 || mustfree == 3) {
    free(adjwgt);
    graph->adjwgt = NULL;
  }

  GKfree((void**)&kpwgts, &padjncy, &padjwgt, &padjcut, LTERM);
}
Example #5
0
/*************************************************************************
* This function reads a mesh from a file
**************************************************************************/
void ParallelReadMesh(MeshType *mesh, char *filename, MPI_Comm comm)
{
  int i, j, k, pe;
  int npes, mype, ier;
  int gnelms, nelms, your_nelms, etype, maxnelms;
  int maxnode, gmaxnode, minnode, gminnode;
  idxtype *elmdist, *elements;
  idxtype *your_elements;
  MPI_Status stat;
  char *line = NULL, *oldstr, *newstr;
  FILE *fpin = NULL;
  int esize, esizes[5] = {-1, 3, 4, 8, 4};
  int mgcnum, mgcnums[5] = {-1, 2, 3, 4, 2};

  MPI_Comm_size(comm, &npes);
  MPI_Comm_rank(comm, &mype);

  elmdist = mesh->elmdist = idxsmalloc(npes+1, 0, "ReadGraph: elmdist");

  if (mype == npes-1) {
    ier = 0;
    fpin = fopen(filename, "r");

    if (fpin == NULL){
      printf("COULD NOT OPEN FILE '%s' FOR SOME REASON!\n", filename);
      ier++;
    }

    MPI_Bcast(&ier, 1, MPI_INT, npes-1, comm);
    if (ier > 0){
      fclose(fpin);
      MPI_Finalize();
      exit(0);
    }

    line = (char *)GKmalloc(sizeof(char)*(MAXLINE+1), "line");

    fgets(line, MAXLINE, fpin);
    sscanf(line, "%d %d", &gnelms, &etype);

    /* Construct elmdist and send it to all the processors */
    elmdist[0] = 0;
    for (i=0,j=gnelms; i<npes; i++) {
      k = j/(npes-i);
      elmdist[i+1] = elmdist[i]+k;
      j -= k;
    }

    MPI_Bcast((void *)elmdist, npes+1, IDX_DATATYPE, npes-1, comm);
  }
  else {
    MPI_Bcast(&ier, 1, MPI_INT, npes-1, comm);
    if (ier > 0){
      MPI_Finalize();
      exit(0);
    }

    MPI_Bcast((void *)elmdist, npes+1, IDX_DATATYPE, npes-1, comm);
  }

  MPI_Bcast((void *)(&etype), 1, MPI_INT, npes-1, comm);

  gnelms = mesh->gnelms = elmdist[npes];
  nelms = mesh->nelms = elmdist[mype+1]-elmdist[mype];
  mesh->etype = etype;
  esize = esizes[etype];
  mgcnum = mgcnums[etype];

  elements = mesh->elements = idxmalloc(nelms*esize, "ParallelReadMesh: elements");

  if (mype == npes-1) {
    maxnelms = 0;
    for (i=0; i<npes; i++) {
      maxnelms = (maxnelms > elmdist[i+1]-elmdist[i]) ?
      maxnelms : elmdist[i+1]-elmdist[i];
    }

    your_elements = idxmalloc(maxnelms*esize, "your_elements");

    for (pe=0; pe<npes; pe++) {
      your_nelms = elmdist[pe+1]-elmdist[pe];
      for (i=0; i<your_nelms; i++) {

        fgets(line, MAXLINE, fpin);
        oldstr = line;
        newstr = NULL;

        /*************************************/
        /* could get element weigts here too */
        /*************************************/

        for (j=0; j<esize; j++) {
          your_elements[i*esize+j] = (int)strtol(oldstr, &newstr, 10);
          oldstr = newstr;
        }
      }

      if (pe < npes-1) {
        MPI_Send((void *)your_elements, your_nelms*esize, IDX_DATATYPE, pe, 0, comm);
      }
      else {
        for (i=0; i<your_nelms*esize; i++)
          elements[i] = your_elements[i];
      }
    }
    fclose(fpin);
    free(your_elements);
  }
  else {
    MPI_Recv((void *)elements, nelms*esize, IDX_DATATYPE, npes-1, 0, comm, &stat);
  }

  /*********************************/
  /* now check for number of nodes */
  /*********************************/
  minnode = elements[idxamin(nelms*esize, elements)];
  MPI_Allreduce((void *)&minnode, (void *)&gminnode, 1, MPI_INT, MPI_MIN, comm);
  for (i=0; i<nelms*esize; i++)
    elements[i] -= gminnode;

  maxnode = elements[idxamax(nelms*esize, elements)];
  MPI_Allreduce((void *)&maxnode, (void *)&gmaxnode, 1, MPI_INT, MPI_MAX, comm);
  mesh->gnns = gmaxnode+1;

  if (mype==0) printf("Nelements: %d, Nnodes: %d, EType: %d\n", gnelms, mesh->gnns, etype);
}
Example #6
0
/*************************************************************************
* This function converts a mesh into a dual graph
**************************************************************************/
void ParMETIS_V3_Mesh2Dual(idxtype *elmdist, idxtype *eptr, idxtype *eind, 
                 int *numflag, int *ncommonnodes, idxtype **xadj, 
		 idxtype **adjncy, MPI_Comm *comm)
{
  int i, j, jj, k, kk, m;
  int npes, mype, pe, count, mask, pass;
  int nelms, lnns, my_nns, node;
  int firstelm, firstnode, lnode, nrecv, nsend;
  int *scounts, *rcounts, *sdispl, *rdispl;
  idxtype *nodedist, *nmap, *auxarray;
  idxtype *gnptr, *gnind, *nptr, *nind, *myxadj, *myadjncy = NULL;
  idxtype *sbuffer, *rbuffer, *htable;
  KeyValueType *nodelist, *recvbuffer;
  idxtype ind[200], wgt[200];
  int gmaxnode, gminnode;
  CtrlType ctrl;


  SetUpCtrl(&ctrl, -1, 0, *comm);

  npes = ctrl.npes;
  mype = ctrl.mype;

  nelms = elmdist[mype+1]-elmdist[mype];

  if (*numflag == 1) 
    ChangeNumberingMesh2(elmdist, eptr, eind, NULL, NULL, NULL, npes, mype, 1);

  mask = (1<<11)-1;

  /*****************************/
  /* Determine number of nodes */
  /*****************************/
  gminnode = GlobalSEMin(&ctrl, eind[idxamin(eptr[nelms], eind)]);
  for (i=0; i<eptr[nelms]; i++)
    eind[i] -= gminnode;

  gmaxnode = GlobalSEMax(&ctrl, eind[idxamax(eptr[nelms], eind)]);


  /**************************/
  /* Check for input errors */
  /**************************/
  ASSERTS(nelms > 0);

  /* construct node distribution array */
  nodedist = idxsmalloc(npes+1, 0, "nodedist");
  for (nodedist[0]=0, i=0,j=gmaxnode+1; i<npes; i++) {
    k = j/(npes-i);
    nodedist[i+1] = nodedist[i]+k;
    j -= k;
  }
  my_nns = nodedist[mype+1]-nodedist[mype];
  firstnode = nodedist[mype];

  nodelist = (KeyValueType *)GKmalloc(eptr[nelms]*sizeof(KeyValueType), "nodelist");
  auxarray = idxmalloc(eptr[nelms], "auxarray");
  htable   = idxsmalloc(amax(my_nns, mask+1), -1, "htable");
  scounts  = imalloc(4*npes+2, "scounts");
  rcounts  = scounts+npes;
  sdispl   = scounts+2*npes;
  rdispl   = scounts+3*npes+1;


  /*********************************************/
  /* first find a local numbering of the nodes */
  /*********************************************/
  for (i=0; i<nelms; i++) {
    for (j=eptr[i]; j<eptr[i+1]; j++) {
      nodelist[j].key = eind[j];
      nodelist[j].val = j;
      auxarray[j]     = i; /* remember the local element ID that uses this node */
    }
  }
  ikeysort(eptr[nelms], nodelist);

  for (count=1, i=1; i<eptr[nelms]; i++) {
    if (nodelist[i].key > nodelist[i-1].key)
      count++;
  }

  lnns = count;
  nmap = idxmalloc(lnns, "nmap");

  /* renumber the nodes of the elements array */
  count = 1;
  nmap[0] = nodelist[0].key;
  eind[nodelist[0].val] = 0;
  nodelist[0].val = auxarray[nodelist[0].val];  /* Store the local element ID */
  for (i=1; i<eptr[nelms]; i++) {
    if (nodelist[i].key > nodelist[i-1].key) {
      nmap[count] = nodelist[i].key;
      count++;
    }
    eind[nodelist[i].val] = count-1;
    nodelist[i].val = auxarray[nodelist[i].val];  /* Store the local element ID */
  }
  MPI_Barrier(*comm);

  /**********************************************************/
  /* perform comms necessary to construct node-element list */
  /**********************************************************/
  iset(npes, 0, scounts);
  for (pe=i=0; i<eptr[nelms]; i++) {
    while (nodelist[i].key >= nodedist[pe+1])
      pe++;
    scounts[pe] += 2;
  }
  ASSERTS(pe < npes);

  MPI_Alltoall((void *)scounts, 1, MPI_INT, (void *)rcounts, 1, MPI_INT, *comm);

  icopy(npes, scounts, sdispl);
  MAKECSR(i, npes, sdispl);

  icopy(npes, rcounts, rdispl);
  MAKECSR(i, npes, rdispl);

  ASSERTS(sdispl[npes] == eptr[nelms]*2);

  nrecv = rdispl[npes]/2;
  recvbuffer = (KeyValueType *)GKmalloc(amax(1, nrecv)*sizeof(KeyValueType), "recvbuffer");

  MPI_Alltoallv((void *)nodelist, scounts, sdispl, IDX_DATATYPE, (void *)recvbuffer, 
                rcounts, rdispl, IDX_DATATYPE, *comm);

  /**************************************/
  /* construct global node-element list */
  /**************************************/
  gnptr = idxsmalloc(my_nns+1, 0, "gnptr");

  for (i=0; i<npes; i++) {
    for (j=rdispl[i]/2; j<rdispl[i+1]/2; j++) {
      lnode = recvbuffer[j].key-firstnode;
      ASSERTS(lnode >= 0 && lnode < my_nns)

      gnptr[lnode]++;
    }
  }
  MAKECSR(i, my_nns, gnptr);

  gnind = idxmalloc(amax(1, gnptr[my_nns]), "gnind");
  for (pe=0; pe<npes; pe++) {
    firstelm = elmdist[pe];
    for (j=rdispl[pe]/2; j<rdispl[pe+1]/2; j++) {
      lnode = recvbuffer[j].key-firstnode;
      gnind[gnptr[lnode]++] = recvbuffer[j].val+firstelm;
    }
  }
  SHIFTCSR(i, my_nns, gnptr);


  /*********************************************************/
  /* send the node-element info to the relevant processors */
  /*********************************************************/
  iset(npes, 0, scounts);

  /* use a hash table to ensure that each node is sent to a proc only once */
  for (pe=0; pe<npes; pe++) {
    for (j=rdispl[pe]/2; j<rdispl[pe+1]/2; j++) {
      lnode = recvbuffer[j].key-firstnode;
      if (htable[lnode] == -1) {
        scounts[pe] += gnptr[lnode+1]-gnptr[lnode];
        htable[lnode] = 1;
      }
    }

    /* now reset the hash table */
    for (j=rdispl[pe]/2; j<rdispl[pe+1]/2; j++) {
      lnode = recvbuffer[j].key-firstnode;
      htable[lnode] = -1;
    }
  }


  MPI_Alltoall((void *)scounts, 1, MPI_INT, (void *)rcounts, 1, MPI_INT, *comm);

  icopy(npes, scounts, sdispl);
  MAKECSR(i, npes, sdispl);

  /* create the send buffer */
  nsend = sdispl[npes];
  sbuffer = (idxtype *)realloc(nodelist, sizeof(idxtype)*amax(1, nsend));

  count = 0;
  for (pe=0; pe<npes; pe++) {
    for (j=rdispl[pe]/2; j<rdispl[pe+1]/2; j++) {
      lnode = recvbuffer[j].key-firstnode;
      if (htable[lnode] == -1) {
        for (k=gnptr[lnode]; k<gnptr[lnode+1]; k++) {
          if (k == gnptr[lnode])
            sbuffer[count++] = -1*(gnind[k]+1);
          else
            sbuffer[count++] = gnind[k];
        }
        htable[lnode] = 1;
      }
    }
    ASSERTS(count == sdispl[pe+1]);

    /* now reset the hash table */
    for (j=rdispl[pe]/2; j<rdispl[pe+1]/2; j++) {
      lnode = recvbuffer[j].key-firstnode;
      htable[lnode] = -1;
    }
  }

  icopy(npes, rcounts, rdispl);
  MAKECSR(i, npes, rdispl);

  nrecv = rdispl[npes];
  rbuffer = (idxtype *)realloc(recvbuffer, sizeof(idxtype)*amax(1, nrecv));

  MPI_Alltoallv((void *)sbuffer, scounts, sdispl, IDX_DATATYPE, (void *)rbuffer, 
                rcounts, rdispl, IDX_DATATYPE, *comm);

  k = -1;
  nptr = idxsmalloc(lnns+1, 0, "nptr");
  nind = rbuffer;
  for (pe=0; pe<npes; pe++) {
    for (j=rdispl[pe]; j<rdispl[pe+1]; j++) {
      if (nind[j] < 0) {
        k++;
        nind[j] = (-1*nind[j])-1;
      }
      nptr[k]++;
    }
  }
  MAKECSR(i, lnns, nptr);

  ASSERTS(k+1 == lnns);
  ASSERTS(nptr[lnns] == nrecv)

  myxadj = *xadj = idxsmalloc(nelms+1, 0, "xadj");
  idxset(mask+1, -1, htable);

  firstelm = elmdist[mype];

  /* Two passes -- in first pass, simply find out the memory requirements */
  for (pass=0; pass<2; pass++) {
    for (i=0; i<nelms; i++) {
      for (count=0, j=eptr[i]; j<eptr[i+1]; j++) {
        node = eind[j];

        for (k=nptr[node]; k<nptr[node+1]; k++) {
          if ((kk=nind[k]) == firstelm+i) 
	    continue;
	    
          m = htable[(kk&mask)];

          if (m == -1) {
            ind[count] = kk;
            wgt[count] = 1;
            htable[(kk&mask)] = count++;
          }
          else {
            if (ind[m] == kk) { 
              wgt[m]++;
            }
            else {
              for (jj=0; jj<count; jj++) {
                if (ind[jj] == kk) {
                  wgt[jj]++;
                  break;
	        }
              }
              if (jj == count) {
                ind[count]   = kk;
                wgt[count++] = 1;
              }
	    }
          }
        }
      }

      for (j=0; j<count; j++) {
        htable[(ind[j]&mask)] = -1;
        if (wgt[j] >= *ncommonnodes) {
          if (pass == 0) 
            myxadj[i]++;
          else 
            myadjncy[myxadj[i]++] = ind[j];
	}
      }
    }

    if (pass == 0) {
      MAKECSR(i, nelms, myxadj);
      myadjncy = *adjncy = idxmalloc(myxadj[nelms], "adjncy");
    }
    else {
      SHIFTCSR(i, nelms, myxadj);
    }
  }

  /*****************************************/
  /* correctly renumber the elements array */
  /*****************************************/
  for (i=0; i<eptr[nelms]; i++)
    eind[i] = nmap[eind[i]] + gminnode;

  if (*numflag == 1) 
    ChangeNumberingMesh2(elmdist, eptr, eind, myxadj, myadjncy, NULL, npes, mype, 0);

  /* do not free nodelist, recvbuffer, rbuffer */
  GKfree((void **)&scounts, (void **)&nodedist, (void **)&nmap, (void **)&sbuffer, 
         (void **)&htable, (void **)&nptr, (void **)&nind, (void **)&gnptr, 
	 (void **)&gnind, (void **)&auxarray, LTERM);

  FreeCtrl(&ctrl);

  return;
}