[2051] | 1 | /* |
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| 2 | * Copyright 1997, Regents of the University of Minnesota |
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| 3 | * |
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| 4 | * fm.c |
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| 5 | * |
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| 6 | * This file contains code that implements the edge-based FM refinement |
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| 7 | * |
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| 8 | * Started 7/23/97 |
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| 9 | * George |
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| 10 | * |
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| 11 | * $Id: fm.c,v 1.1 1998/11/27 17:59:14 karypis Exp $ |
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| 12 | */ |
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| 13 | |
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| 14 | #include <metis.h> |
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| 15 | |
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| 16 | |
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| 17 | /************************************************************************* |
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| 18 | * This function performs an edge-based FM refinement |
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| 19 | **************************************************************************/ |
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| 20 | void FM_2WayEdgeRefine(CtrlType *ctrl, GraphType *graph, int *tpwgts, int npasses) |
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| 21 | { |
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| 22 | int i, ii, j, k, kwgt, nvtxs, nbnd, nswaps, from, to, pass, me, limit, tmp; |
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| 23 | idxtype *xadj, *vwgt, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind, *pwgts; |
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| 24 | idxtype *moved, *swaps, *perm; |
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| 25 | PQueueType parts[2]; |
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| 26 | int higain, oldgain, mincut, mindiff, origdiff, initcut, newcut, mincutorder, avgvwgt; |
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| 27 | |
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| 28 | nvtxs = graph->nvtxs; |
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| 29 | xadj = graph->xadj; |
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| 30 | vwgt = graph->vwgt; |
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| 31 | adjncy = graph->adjncy; |
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| 32 | adjwgt = graph->adjwgt; |
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| 33 | where = graph->where; |
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| 34 | id = graph->id; |
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| 35 | ed = graph->ed; |
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| 36 | pwgts = graph->pwgts; |
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| 37 | bndptr = graph->bndptr; |
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| 38 | bndind = graph->bndind; |
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| 39 | |
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| 40 | moved = idxwspacemalloc(ctrl, nvtxs); |
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| 41 | swaps = idxwspacemalloc(ctrl, nvtxs); |
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| 42 | perm = idxwspacemalloc(ctrl, nvtxs); |
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| 43 | |
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| 44 | limit = amin(amax(0.01*nvtxs, 15), 100); |
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| 45 | avgvwgt = amin((pwgts[0]+pwgts[1])/20, 2*(pwgts[0]+pwgts[1])/nvtxs); |
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| 46 | |
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| 47 | tmp = graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)]; |
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| 48 | PQueueInit(ctrl, &parts[0], nvtxs, tmp); |
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| 49 | PQueueInit(ctrl, &parts[1], nvtxs, tmp); |
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| 50 | |
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| 51 | IFSET(ctrl->dbglvl, DBG_REFINE, |
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| 52 | printf("Partitions: [%6d %6d] T[%6d %6d], Nv-Nb[%6d %6d]. ICut: %6d\n", |
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| 53 | pwgts[0], pwgts[1], tpwgts[0], tpwgts[1], graph->nvtxs, graph->nbnd, graph->mincut)); |
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| 54 | |
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| 55 | origdiff = abs(tpwgts[0]-pwgts[0]); |
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| 56 | idxset(nvtxs, -1, moved); |
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| 57 | for (pass=0; pass<npasses; pass++) { /* Do a number of passes */ |
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| 58 | PQueueReset(&parts[0]); |
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| 59 | PQueueReset(&parts[1]); |
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| 60 | |
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| 61 | mincutorder = -1; |
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| 62 | newcut = mincut = initcut = graph->mincut; |
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| 63 | mindiff = abs(tpwgts[0]-pwgts[0]); |
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| 64 | |
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| 65 | ASSERT(ComputeCut(graph, where) == graph->mincut); |
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| 66 | ASSERT(CheckBnd(graph)); |
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| 67 | |
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| 68 | /* Insert boundary nodes in the priority queues */ |
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| 69 | nbnd = graph->nbnd; |
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| 70 | RandomPermute(nbnd, perm, 1); |
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| 71 | for (ii=0; ii<nbnd; ii++) { |
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| 72 | i = perm[ii]; |
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| 73 | ASSERT(ed[bndind[i]] > 0 || id[bndind[i]] == 0); |
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| 74 | ASSERT(bndptr[bndind[i]] != -1); |
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| 75 | PQueueInsert(&parts[where[bndind[i]]], bndind[i], ed[bndind[i]]-id[bndind[i]]); |
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| 76 | } |
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| 77 | |
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| 78 | for (nswaps=0; nswaps<nvtxs; nswaps++) { |
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| 79 | from = (tpwgts[0]-pwgts[0] < tpwgts[1]-pwgts[1] ? 0 : 1); |
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| 80 | to = (from+1)%2; |
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| 81 | |
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| 82 | if ((higain = PQueueGetMax(&parts[from])) == -1) |
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| 83 | break; |
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| 84 | ASSERT(bndptr[higain] != -1); |
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| 85 | |
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| 86 | newcut -= (ed[higain]-id[higain]); |
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| 87 | INC_DEC(pwgts[to], pwgts[from], vwgt[higain]); |
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| 88 | |
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| 89 | if ((newcut < mincut && abs(tpwgts[0]-pwgts[0]) <= origdiff+avgvwgt) || |
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| 90 | (newcut == mincut && abs(tpwgts[0]-pwgts[0]) < mindiff)) { |
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| 91 | mincut = newcut; |
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| 92 | mindiff = abs(tpwgts[0]-pwgts[0]); |
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| 93 | mincutorder = nswaps; |
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| 94 | } |
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| 95 | else if (nswaps-mincutorder > limit) { /* We hit the limit, undo last move */ |
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| 96 | newcut += (ed[higain]-id[higain]); |
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| 97 | INC_DEC(pwgts[from], pwgts[to], vwgt[higain]); |
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| 98 | break; |
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| 99 | } |
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| 100 | |
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| 101 | where[higain] = to; |
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| 102 | moved[higain] = nswaps; |
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| 103 | swaps[nswaps] = higain; |
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| 104 | |
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| 105 | IFSET(ctrl->dbglvl, DBG_MOVEINFO, |
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| 106 | printf("Moved %6d from %d. [%3d %3d] %5d [%4d %4d]\n", higain, from, ed[higain]-id[higain], vwgt[higain], newcut, pwgts[0], pwgts[1])); |
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| 107 | |
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| 108 | /************************************************************** |
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| 109 | * Update the id[i]/ed[i] values of the affected nodes |
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| 110 | ***************************************************************/ |
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| 111 | SWAP(id[higain], ed[higain], tmp); |
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| 112 | if (ed[higain] == 0 && xadj[higain] < xadj[higain+1]) |
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| 113 | BNDDelete(nbnd, bndind, bndptr, higain); |
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| 114 | |
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| 115 | for (j=xadj[higain]; j<xadj[higain+1]; j++) { |
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| 116 | k = adjncy[j]; |
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| 117 | oldgain = ed[k]-id[k]; |
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| 118 | |
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| 119 | kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]); |
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| 120 | INC_DEC(id[k], ed[k], kwgt); |
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| 121 | |
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| 122 | /* Update its boundary information and queue position */ |
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| 123 | if (bndptr[k] != -1) { /* If k was a boundary vertex */ |
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| 124 | if (ed[k] == 0) { /* Not a boundary vertex any more */ |
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| 125 | BNDDelete(nbnd, bndind, bndptr, k); |
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| 126 | if (moved[k] == -1) /* Remove it if in the queues */ |
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| 127 | PQueueDelete(&parts[where[k]], k, oldgain); |
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| 128 | } |
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| 129 | else { /* If it has not been moved, update its position in the queue */ |
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| 130 | if (moved[k] == -1) |
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| 131 | PQueueUpdate(&parts[where[k]], k, oldgain, ed[k]-id[k]); |
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| 132 | } |
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| 133 | } |
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| 134 | else { |
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| 135 | if (ed[k] > 0) { /* It will now become a boundary vertex */ |
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| 136 | BNDInsert(nbnd, bndind, bndptr, k); |
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| 137 | if (moved[k] == -1) |
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| 138 | PQueueInsert(&parts[where[k]], k, ed[k]-id[k]); |
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| 139 | } |
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| 140 | } |
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| 141 | } |
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| 142 | |
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| 143 | } |
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| 144 | |
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| 145 | |
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| 146 | /**************************************************************** |
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| 147 | * Roll back computations |
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| 148 | *****************************************************************/ |
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| 149 | for (i=0; i<nswaps; i++) |
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| 150 | moved[swaps[i]] = -1; /* reset moved array */ |
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| 151 | for (nswaps--; nswaps>mincutorder; nswaps--) { |
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| 152 | higain = swaps[nswaps]; |
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| 153 | |
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| 154 | to = where[higain] = (where[higain]+1)%2; |
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| 155 | SWAP(id[higain], ed[higain], tmp); |
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| 156 | if (ed[higain] == 0 && bndptr[higain] != -1 && xadj[higain] < xadj[higain+1]) |
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| 157 | BNDDelete(nbnd, bndind, bndptr, higain); |
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| 158 | else if (ed[higain] > 0 && bndptr[higain] == -1) |
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| 159 | BNDInsert(nbnd, bndind, bndptr, higain); |
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| 160 | |
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| 161 | INC_DEC(pwgts[to], pwgts[(to+1)%2], vwgt[higain]); |
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| 162 | for (j=xadj[higain]; j<xadj[higain+1]; j++) { |
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| 163 | k = adjncy[j]; |
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| 164 | |
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| 165 | kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]); |
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| 166 | INC_DEC(id[k], ed[k], kwgt); |
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| 167 | |
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| 168 | if (bndptr[k] != -1 && ed[k] == 0) |
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| 169 | BNDDelete(nbnd, bndind, bndptr, k); |
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| 170 | if (bndptr[k] == -1 && ed[k] > 0) |
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| 171 | BNDInsert(nbnd, bndind, bndptr, k); |
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| 172 | } |
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| 173 | } |
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| 174 | |
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| 175 | IFSET(ctrl->dbglvl, DBG_REFINE, |
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| 176 | printf("\tMinimum cut: %6d at %5d, PWGTS: [%6d %6d], NBND: %6d\n", mincut, mincutorder, pwgts[0], pwgts[1], nbnd)); |
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| 177 | |
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| 178 | graph->mincut = mincut; |
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| 179 | graph->nbnd = nbnd; |
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| 180 | |
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| 181 | if (mincutorder == -1 || mincut == initcut) |
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| 182 | break; |
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| 183 | } |
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| 184 | |
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| 185 | PQueueFree(ctrl, &parts[0]); |
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| 186 | PQueueFree(ctrl, &parts[1]); |
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| 187 | |
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| 188 | idxwspacefree(ctrl, nvtxs); |
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| 189 | idxwspacefree(ctrl, nvtxs); |
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| 190 | idxwspacefree(ctrl, nvtxs); |
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| 191 | |
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| 192 | } |
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| 193 | |
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| 194 | |
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