ccgraph.c

一个用来实现偏微分方程中网格的计算库

        cadjwgt[j] = cadjwgt[nedges];
        htable[cnvtxs] = -1;
      }
    }

    ASSERTP(cadjwgtsum[cnvtxs] == idxsum(nedges, cadjwgt), ("%d %d\n", cadjwgtsum[cnvtxs], idxsum(nedges, cadjwgt)));

    for (j=0; j<nedges; j++)
      htable[cadjncy[j]] = -1;  /* Zero out the htable */

    cnedges += nedges;
    cxadj[++cnvtxs] = cnedges;
    cadjncy += nedges;
    cadjwgt += nedges;
  }

  cgraph->nedges = cnedges;

  ReAdjustMemory(graph, cgraph, dovsize);

  IFSET(ctrl->dbglvl, DBG_TIME, stoptimer(ctrl->ContractTmr));

  idxwspacefree(ctrl, cnvtxs);
}


/*************************************************************************
* This function creates the coarser graph
**************************************************************************/
void CreateCoarseGraph_NVW(CtrlType *ctrl, GraphType *graph, int cnvtxs, idxtype *match, idxtype *perm)
{
  int i, j, jj, k, kk, l, m, istart, iend, nvtxs, nedges, ncon, cnedges, v, u, mask;
  idxtype *xadj, *adjncy, *adjwgtsum, *auxadj;
  idxtype *cmap, *htable;
  idxtype *cxadj, *cvwgt, *cadjncy, *cadjwgt, *cadjwgtsum;
  float *nvwgt, *cnvwgt;
  GraphType *cgraph;


  IFSET(ctrl->dbglvl, DBG_TIME, starttimer(ctrl->ContractTmr));

  nvtxs = graph->nvtxs;
  ncon = graph->ncon;
  xadj = graph->xadj;
  nvwgt = graph->nvwgt;
  adjncy = graph->adjncy;
  adjwgtsum = graph->adjwgtsum;
  cmap = graph->cmap;

  /* Initialize the coarser graph */
  cgraph = SetUpCoarseGraph(graph, cnvtxs, 0);
  cxadj = cgraph->xadj;
  cvwgt = cgraph->vwgt;
  cnvwgt = cgraph->nvwgt;
  cadjwgtsum = cgraph->adjwgtsum;
  cadjncy = cgraph->adjncy;
  cadjwgt = cgraph->adjwgt;


  iend = xadj[nvtxs];
  auxadj = ctrl->wspace.auxcore; 
  memcpy(auxadj, adjncy, iend*sizeof(idxtype)); 
  for (i=0; i<iend; i++)
    auxadj[i] = cmap[auxadj[i]];

  mask = HTLENGTH;
  htable = idxset(mask+1, -1, idxwspacemalloc(ctrl, mask+1)); 

  cxadj[0] = cnvtxs = cnedges = 0;
  for (i=0; i<nvtxs; i++) {
    v = perm[i];
    if (cmap[v] != cnvtxs) 
      continue;

    u = match[v];
    cvwgt[cnvtxs] = 1;
    cadjwgtsum[cnvtxs] = adjwgtsum[v];
    nedges = 0;

    istart = xadj[v];
    iend = xadj[v+1];
    for (j=istart; j<iend; j++) {
      k = auxadj[j];
      kk = k&mask;
      if ((m = htable[kk]) == -1) {
        cadjncy[nedges] = k;
        cadjwgt[nedges] = 1;
        htable[kk] = nedges++;
      }
      else if (cadjncy[m] == k) {
        cadjwgt[m]++;
      }
      else {
        for (jj=0; jj<nedges; jj++) {
          if (cadjncy[jj] == k) {
            cadjwgt[jj]++;
            break;
          }
        }
        if (jj == nedges) {
          cadjncy[nedges] = k;
          cadjwgt[nedges++] = 1;
        }
      }
    }

    if (v != u) { 
      cvwgt[cnvtxs]++;
      cadjwgtsum[cnvtxs] += adjwgtsum[u];

      istart = xadj[u];
      iend = xadj[u+1];
      for (j=istart; j<iend; j++) {
        k = auxadj[j];
        kk = k&mask;
        if ((m = htable[kk]) == -1) {
          cadjncy[nedges] = k;
          cadjwgt[nedges] = 1;
          htable[kk] = nedges++;
        }
        else if (cadjncy[m] == k) {
          cadjwgt[m]++;
        }
        else {
          for (jj=0; jj<nedges; jj++) {
            if (cadjncy[jj] == k) {
              cadjwgt[jj]++;
              break;
            }
          }
          if (jj == nedges) {
            cadjncy[nedges] = k;
            cadjwgt[nedges++] = 1;
          }
        }
      }

      /* Remove the contracted adjacency weight */
      jj = htable[cnvtxs&mask];
      if (jj >= 0 && cadjncy[jj] != cnvtxs) {
        for (jj=0; jj<nedges; jj++) {
          if (cadjncy[jj] == cnvtxs) 
            break;
        }
      }
      if (jj >= 0 && cadjncy[jj] == cnvtxs) { /* This 2nd check is needed for non-adjacent matchings */
        cadjwgtsum[cnvtxs] -= cadjwgt[jj];
        cadjncy[jj] = cadjncy[--nedges];
        cadjwgt[jj] = cadjwgt[nedges];
      }
    }

    ASSERTP(cadjwgtsum[cnvtxs] == idxsum(nedges, cadjwgt), ("%d %d %d %d %d\n", cnvtxs, cadjwgtsum[cnvtxs], idxsum(nedges, cadjwgt), adjwgtsum[u], adjwgtsum[v]));

    for (j=0; j<nedges; j++)
      htable[cadjncy[j]&mask] = -1;  /* Zero out the htable */
    htable[cnvtxs&mask] = -1;

    cnedges += nedges;
    cxadj[++cnvtxs] = cnedges;
    cadjncy += nedges;
    cadjwgt += nedges;
  }

  cgraph->nedges = cnedges;

  ReAdjustMemory(graph, cgraph, 0);

  IFSET(ctrl->dbglvl, DBG_TIME, stoptimer(ctrl->ContractTmr));

  idxwspacefree(ctrl, mask+1);

}


/*************************************************************************
* Setup the various arrays for the coarse graph
**************************************************************************/
GraphType *SetUpCoarseGraph(GraphType *graph, int cnvtxs, int dovsize)
{
  GraphType *cgraph;

  cgraph = CreateGraph();
  cgraph->nvtxs = cnvtxs;
  cgraph->ncon = graph->ncon;

  cgraph->finer = graph;
  graph->coarser = cgraph;


  /* Allocate memory for the coarser graph */
  if (graph->ncon == 1) {
    if (dovsize) {
      cgraph->gdata = idxmalloc(5*cnvtxs+1 + 2*graph->nedges, "SetUpCoarseGraph: gdata");
      cgraph->xadj 		= cgraph->gdata;
      cgraph->vwgt 		= cgraph->gdata + cnvtxs+1;
      cgraph->vsize 		= cgraph->gdata + 2*cnvtxs+1;
      cgraph->adjwgtsum 	= cgraph->gdata + 3*cnvtxs+1;
      cgraph->cmap 		= cgraph->gdata + 4*cnvtxs+1;
      cgraph->adjncy 		= cgraph->gdata + 5*cnvtxs+1;
      cgraph->adjwgt 		= cgraph->gdata + 5*cnvtxs+1 + graph->nedges;
    }
    else {
      cgraph->gdata = idxmalloc(4*cnvtxs+1 + 2*graph->nedges, "SetUpCoarseGraph: gdata");
      cgraph->xadj 		= cgraph->gdata;
      cgraph->vwgt 		= cgraph->gdata + cnvtxs+1;
      cgraph->adjwgtsum 	= cgraph->gdata + 2*cnvtxs+1;
      cgraph->cmap 		= cgraph->gdata + 3*cnvtxs+1;
      cgraph->adjncy 		= cgraph->gdata + 4*cnvtxs+1;
      cgraph->adjwgt 		= cgraph->gdata + 4*cnvtxs+1 + graph->nedges;
    }
  }
  else {
    if (dovsize) {
      cgraph->gdata = idxmalloc(4*cnvtxs+1 + 2*graph->nedges, "SetUpCoarseGraph: gdata");
      cgraph->xadj 		= cgraph->gdata;
      cgraph->vsize 		= cgraph->gdata + cnvtxs+1;
      cgraph->adjwgtsum 	= cgraph->gdata + 2*cnvtxs+1;
      cgraph->cmap 		= cgraph->gdata + 3*cnvtxs+1;
      cgraph->adjncy 		= cgraph->gdata + 4*cnvtxs+1;
      cgraph->adjwgt 		= cgraph->gdata + 4*cnvtxs+1 + graph->nedges;
    }
    else {
      cgraph->gdata = idxmalloc(3*cnvtxs+1 + 2*graph->nedges, "SetUpCoarseGraph: gdata");
      cgraph->xadj 		= cgraph->gdata;
      cgraph->adjwgtsum 	= cgraph->gdata + cnvtxs+1;
      cgraph->cmap 		= cgraph->gdata + 2*cnvtxs+1;
      cgraph->adjncy 		= cgraph->gdata + 3*cnvtxs+1;
      cgraph->adjwgt 		= cgraph->gdata + 3*cnvtxs+1 + graph->nedges;
    }

    cgraph->nvwgt 	= fmalloc(graph->ncon*cnvtxs, "SetUpCoarseGraph: nvwgt");
  }

  return cgraph;
}


/*************************************************************************
* This function re-adjusts the amount of memory that was allocated if
* it will lead to significant savings
**************************************************************************/
void ReAdjustMemory(GraphType *graph, GraphType *cgraph, int dovsize) 
{

  if (cgraph->nedges > 100000 && graph->nedges < 0.7*graph->nedges) {
    idxcopy(cgraph->nedges, cgraph->adjwgt, cgraph->adjncy+cgraph->nedges);

    if (graph->ncon == 1) {
      if (dovsize) {
        cgraph->gdata = realloc(cgraph->gdata, (5*cgraph->nvtxs+1 + 2*cgraph->nedges)*sizeof(idxtype));

        /* Do this, in case everything was copied into new space */
        cgraph->xadj 		= cgraph->gdata;
        cgraph->vwgt 		= cgraph->gdata + cgraph->nvtxs+1;
        cgraph->vsize 		= cgraph->gdata + 2*cgraph->nvtxs+1;
        cgraph->adjwgtsum	= cgraph->gdata + 3*cgraph->nvtxs+1;
        cgraph->cmap 		= cgraph->gdata + 4*cgraph->nvtxs+1;
        cgraph->adjncy 		= cgraph->gdata + 5*cgraph->nvtxs+1;
        cgraph->adjwgt 		= cgraph->gdata + 5*cgraph->nvtxs+1 + cgraph->nedges;
      }
      else {
        cgraph->gdata = realloc(cgraph->gdata, (4*cgraph->nvtxs+1 + 2*cgraph->nedges)*sizeof(idxtype));

        /* Do this, in case everything was copied into new space */
        cgraph->xadj 	= cgraph->gdata;
        cgraph->vwgt 	= cgraph->gdata + cgraph->nvtxs+1;
        cgraph->adjwgtsum	= cgraph->gdata + 2*cgraph->nvtxs+1;
        cgraph->cmap 	= cgraph->gdata + 3*cgraph->nvtxs+1;
        cgraph->adjncy 	= cgraph->gdata + 4*cgraph->nvtxs+1;
        cgraph->adjwgt 	= cgraph->gdata + 4*cgraph->nvtxs+1 + cgraph->nedges;
      }
    }
    else {
      if (dovsize) {
        cgraph->gdata = realloc(cgraph->gdata, (4*cgraph->nvtxs+1 + 2*cgraph->nedges)*sizeof(idxtype));

        /* Do this, in case everything was copied into new space */
        cgraph->xadj 		= cgraph->gdata;
        cgraph->vsize		= cgraph->gdata + cgraph->nvtxs+1;
        cgraph->adjwgtsum	= cgraph->gdata + 2*cgraph->nvtxs+1;
        cgraph->cmap 		= cgraph->gdata + 3*cgraph->nvtxs+1;
        cgraph->adjncy 		= cgraph->gdata + 4*cgraph->nvtxs+1;
        cgraph->adjwgt 		= cgraph->gdata + 4*cgraph->nvtxs+1 + cgraph->nedges;
      }
      else {
        cgraph->gdata = realloc(cgraph->gdata, (3*cgraph->nvtxs+1 + 2*cgraph->nedges)*sizeof(idxtype));

        /* Do this, in case everything was copied into new space */
        cgraph->xadj 		= cgraph->gdata;
        cgraph->adjwgtsum	= cgraph->gdata + cgraph->nvtxs+1;
        cgraph->cmap 		= cgraph->gdata + 2*cgraph->nvtxs+1;
        cgraph->adjncy 		= cgraph->gdata + 3*cgraph->nvtxs+1;
        cgraph->adjwgt 		= cgraph->gdata + 3*cgraph->nvtxs+1 + cgraph->nedges;
      }
    }
  }

}