 /* 
  * Copyright 1997, Regents of the University of Minnesota 
  * 
  * mfm2.c 
  * 
  * This file contains code that implements the edge-based FM refinement 
  * 
  * Started 7/23/97 
  * George 
  * 
  * $Id: mfm2.c,v 1.2 1998/11/30 14:50:44 karypis Exp $ 
  */ 

 #include <metis.h> 


 /************************************************************************* 
 * This function performs an edge-based FM refinement 
 **************************************************************************/ 
 void MocFM_2WayEdgeRefine2(CtrlType *ctrl, GraphType *graph, float *tpwgts, float *orgubvec,  
        long npasses) 
 { 
   long i, ii, j, k, l, kwgt, nvtxs, ncon, nbnd, nswaps, from, to, pass, me, limit, tmp, cnum; 
   idxtype *xadj, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind; 
   idxtype *moved, *swaps, *perm, *qnum; 
   float *nvwgt, *npwgts, origdiff[MAXNCON], origbal[MAXNCON], minbal[MAXNCON]; 
   PQueueType parts[MAXNCON][2]; 
   long higain, oldgain, mincut, initcut, newcut, mincutorder; 
   float *maxwgt, *minwgt, ubvec[MAXNCON], tvec[MAXNCON]; 

   nvtxs = graph->nvtxs; 
   ncon = graph->ncon; 
   xadj = graph->xadj; 
   nvwgt = graph->nvwgt; 
   adjncy = graph->adjncy; 
   adjwgt = graph->adjwgt; 
   where = graph->where; 
   id = graph->id; 
   ed = graph->ed; 
   npwgts = graph->npwgts; 
   bndptr = graph->bndptr; 
   bndind = graph->bndind; 

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

   limit = amin(amax(0.01*nvtxs, 15), 100); 

   Compute2WayHLoadImbalanceVec(ncon, npwgts, tpwgts, origbal); 
   for (i=0; i<ncon; i++) { 
     origdiff[i] = fabs(tpwgts[0]-npwgts[i]); 
     ubvec[i] = amax(origbal[i], orgubvec[i]); 
   } 

   /* Setup the weight intervals of the two subdomains */ 
   minwgt = fwspacemalloc(ctrl, 2*ncon); 
   maxwgt = fwspacemalloc(ctrl, 2*ncon); 

   for (i=0; i<2; i++) { 
     for (j=0; j<ncon; j++) { 
       maxwgt[i*ncon+j] = tpwgts[i]*ubvec[j]; 
       minwgt[i*ncon+j] = tpwgts[i]*(1.0/ubvec[j]); 
     } 
   } 

   /* Initialize the queues */ 
   for (i=0; i<ncon; i++) { 
     PQueueInit(ctrl, &parts[i][0], nvtxs, PLUS_GAINSPAN+1); 
     PQueueInit(ctrl, &parts[i][1], nvtxs, PLUS_GAINSPAN+1); 
   } 
   for (i=0; i<nvtxs; i++) 
     qnum[i] = samax(ncon, nvwgt+i*ncon); 


   if (ctrl->dbglvl&DBG_REFINE) { 
     printf("Parts: ["); 
     for (l=0; l<ncon; l++) 
       printf("(%.3f, %.3f) ", npwgts[l], npwgts[ncon+l]); 
     printf("] T[%.3f %.3f], Nv-Nb[%5ld, %5ld]. ICut: %6ld, LB: ", tpwgts[0], tpwgts[1],  
             graph->nvtxs, graph->nbnd, graph->mincut); 
     for (i=0; i<ncon; i++) 
       printf("%.3f ", origbal[i]); 
     printf("\n"); 
   } 

   idxset(nvtxs, -1, moved); 
   for (pass=0; pass<npasses; pass++) { /* Do a number of passes */ 
     for (i=0; i<ncon; i++) {  
       PQueueReset(&parts[i][0]); 
       PQueueReset(&parts[i][1]); 
     } 

     mincutorder = -1; 
     newcut = mincut = initcut = graph->mincut; 
     Compute2WayHLoadImbalanceVec(ncon, npwgts, tpwgts, minbal); 

     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 = bndind[perm[ii]]; 
       ASSERT(ed[i] > 0 || id[i] == 0); 
       ASSERT(bndptr[i] != -1); 
       PQueueInsert(&parts[qnum[i]][where[i]], i, ed[i]-id[i]); 
     } 

     for (nswaps=0; nswaps<nvtxs; nswaps++) { 
       SelectQueue2(ncon, npwgts, tpwgts, &from, &cnum, parts, maxwgt); 
       to = (from+1)%2; 

       if (from == -1 || (higain = PQueueGetMax(&parts[cnum][from])) == -1) 
         break; 
       ASSERT(bndptr[higain] != -1); 

       newcut -= (ed[higain]-id[higain]); 
       saxpy(ncon, 1.0, nvwgt+higain*ncon, 1, npwgts+to*ncon, 1); 
       saxpy(ncon, -1.0, nvwgt+higain*ncon, 1, npwgts+from*ncon, 1); 

       Compute2WayHLoadImbalanceVec(ncon, npwgts, tpwgts, tvec); 
       if ((newcut < mincut && AreAllBelow(ncon, tvec, ubvec)) || 
           (newcut == mincut && IsBetter2wayBalance(ncon, tvec, minbal, ubvec))) { 
         mincut = newcut; 
         for (i=0; i<ncon; i++)  
           minbal[i] = tvec[i]; 
         mincutorder = nswaps; 
       } 
       else if (nswaps-mincutorder > limit) { /* We hit the limit, undo last move */ 
         newcut += (ed[higain]-id[higain]); 
         saxpy(ncon, 1.0, nvwgt+higain*ncon, 1, npwgts+from*ncon, 1); 
         saxpy(ncon, -1.0, nvwgt+higain*ncon, 1, npwgts+to*ncon, 1); 
         break; 
       } 

       where[higain] = to; 
       moved[higain] = nswaps; 
       swaps[nswaps] = higain; 

       if (ctrl->dbglvl&DBG_MOVEINFO) { 
         printf("Moved %6ld from %ld(%ld). Gain: %5ld, Cut: %5ld, NPwgts: ", higain, from, cnum, ed[higain]-id[higain], newcut); 
         for (l=0; l<ncon; l++)  
           printf("(%.3f, %.3f) ", npwgts[l], npwgts[ncon+l]); 

         printf(", LB: "); 
         for (i=0; i<ncon; i++)  
           printf("%.3f ", tvec[i]); 
         if (mincutorder == nswaps) 
           printf(" *\n"); 
         else 
           printf("\n"); 
       } 


       /************************************************************** 
       * 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[qnum[k]][where[k]], k, oldgain); 
           } 
           else { /* If it has not been moved, update its position in the queue */ 
             if (moved[k] == -1) 
               PQueueUpdate(&parts[qnum[k]][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[qnum[k]][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); 

       saxpy(ncon, 1.0, nvwgt+higain*ncon, 1, npwgts+to*ncon, 1); 
       saxpy(ncon, -1.0, nvwgt+higain*ncon, 1, npwgts+((to+1)%2)*ncon, 1); 
       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); 
       } 
     } 

     if (ctrl->dbglvl&DBG_REFINE) { 
       printf("\tMincut: %6ld at %5ld, NBND: %6ld, NPwgts: [", mincut, mincutorder, nbnd); 
       for (l=0; l<ncon; l++) 
         printf("(%.3f, %.3f) ", npwgts[l], npwgts[ncon+l]); 
       printf("], LB: "); 
       Compute2WayHLoadImbalanceVec(ncon, npwgts, tpwgts, tvec); 
       for (i=0; i<ncon; i++)  
         printf("%.3f ", tvec[i]); 
       printf("\n"); 
     } 

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

     if (mincutorder == -1 || mincut == initcut) 
       break; 
   } 

   for (i=0; i<ncon; i++) { 
     PQueueFree(ctrl, &parts[i][0]); 
     PQueueFree(ctrl, &parts[i][1]); 
   } 

   idxwspacefree(ctrl, nvtxs); 
   idxwspacefree(ctrl, nvtxs); 
   idxwspacefree(ctrl, nvtxs); 
   idxwspacefree(ctrl, nvtxs); 
   fwspacefree(ctrl, 2*ncon); 
   fwspacefree(ctrl, 2*ncon); 

 } 


 /************************************************************************* 
 * This function selects the partition number and the queue from which 
 * we will move vertices out 
 **************************************************************************/  
 void SelectQueue2(long ncon, float *npwgts, float *tpwgts, long *from, long *cnum,  
        PQueueType queues[MAXNCON][2], float *maxwgt) 
 { 
   long i, j, maxgain=0; 
   float diff, max, maxdiff=0.0; 

   *from = -1; 
   *cnum = -1; 

   /* First determine the side and the queue, irrespective of the presence of nodes */ 
   for (j=0; j<2; j++) { 
     for (i=0; i<ncon; i++) { 
       diff = npwgts[j*ncon+i]-maxwgt[j*ncon+i]; 
       if (diff >= maxdiff) { 
         maxdiff = diff; 
         *from = j; 
         *cnum = i; 
       } 
     } 
   } 

   if (*from != -1 && PQueueGetSize(&queues[*cnum][*from]) == 0) { 
     /* The desired queue is empty, select a node from that side anyway */ 
     for (i=0; i<ncon; i++) { 
       if (PQueueGetSize(&queues[i][*from]) > 0) { 
         max = (npwgts[(*from)*ncon+i] - maxwgt[(*from)*ncon+i]); 
         *cnum = i; 
         break; 
       } 
     } 

     for (i++; i<ncon; i++) { 
       diff = npwgts[(*from)*ncon+i] - maxwgt[(*from)*ncon+i]; 
       if (diff > max && PQueueGetSize(&queues[i][*from]) > 0) { 
         max = diff; 
         *cnum = i; 
       } 
     } 
   } 

   /* Check to see if you can focus on the cut */ 
   if (maxdiff <= 0.0 || *from == -1) { 
     maxgain = -100000; 

     for (j=0; j<2; j++) { 
       for (i=0; i<ncon; i++) { 
         if (PQueueGetSize(&queues[i][j]) > 0 && PQueueGetKey(&queues[i][j]) > maxgain) { 
           maxgain = PQueueGetKey(&queues[i][j]);  
           *from = j; 
           *cnum = i; 
         } 
       } 
     } 

     /* printf("(%2ld %2ld) %3ld\n", *from, *cnum, maxgain); */ 
   } 
 } 


 /************************************************************************* 
 * This function checks if the newbal is better than oldbal given the 
 * ubvector ubvec 
 **************************************************************************/ 
 long IsBetter2wayBalance(long ncon, float *newbal, float *oldbal, float *ubvec) 
 { 
   long i, j; 
   float max1=0.0, max2=0.0, sum1=0.0, sum2=0.0, tmp; 

   for (i=0; i<ncon; i++) { 
     tmp = (newbal[i]-1)/(ubvec[i]-1); 
     max1 = (max1 < tmp ? tmp : max1); 
     sum1 += tmp; 

     tmp = (oldbal[i]-1)/(ubvec[i]-1); 
     max2 = (max2 < tmp ? tmp : max2); 
     sum2 += tmp; 
   } 

   if (max1 < max2) 
     return 1; 
   else if (max1 > max2) 
     return 0; 
   else 
     return sum1 <= sum2; 
 } 


