[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 | * balance.c |
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| 5 | * |
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| 6 | * This file contains code that is used to forcefully balance either |
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| 7 | * bisections or k-sections |
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| 8 | * |
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| 9 | * Started 7/29/97 |
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| 10 | * George |
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| 11 | * |
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| 12 | * $Id: balance.c,v 1.1 1998/11/27 17:59:10 karypis Exp $ |
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| 13 | * |
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| 14 | */ |
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| 15 | |
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| 16 | #include <metis.h> |
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| 17 | |
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| 18 | /************************************************************************* |
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| 19 | * This function is the entry point of the bisection balancing algorithms. |
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| 20 | **************************************************************************/ |
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| 21 | void Balance2Way(CtrlType *ctrl, GraphType *graph, int *tpwgts, float ubfactor) |
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| 22 | { |
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| 23 | int i, j, nvtxs, from, imax, gain, mindiff; |
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| 24 | idxtype *id, *ed; |
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| 25 | |
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| 26 | /* Return right away if the balance is OK */ |
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| 27 | mindiff = abs(tpwgts[0]-graph->pwgts[0]); |
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| 28 | if (mindiff < 3*(graph->pwgts[0]+graph->pwgts[1])/graph->nvtxs) |
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| 29 | return; |
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| 30 | if (graph->pwgts[0] > tpwgts[0] && graph->pwgts[0] < (int)(ubfactor*tpwgts[0])) |
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| 31 | return; |
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| 32 | if (graph->pwgts[1] > tpwgts[1] && graph->pwgts[1] < (int)(ubfactor*tpwgts[1])) |
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| 33 | return; |
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| 34 | |
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| 35 | if (graph->nbnd > 0) |
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| 36 | Bnd2WayBalance(ctrl, graph, tpwgts); |
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| 37 | else |
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| 38 | General2WayBalance(ctrl, graph, tpwgts); |
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| 39 | |
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| 40 | } |
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| 41 | |
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| 42 | |
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| 43 | |
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| 44 | /************************************************************************* |
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| 45 | * This function balances two partitions by moving boundary nodes |
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| 46 | * from the domain that is overweight to the one that is underweight. |
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| 47 | **************************************************************************/ |
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| 48 | void Bnd2WayBalance(CtrlType *ctrl, GraphType *graph, int *tpwgts) |
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| 49 | { |
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| 50 | int i, ii, j, k, kwgt, nvtxs, nbnd, nswaps, from, to, pass, me, tmp; |
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| 51 | idxtype *xadj, *vwgt, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind, *pwgts; |
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| 52 | idxtype *moved, *perm; |
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| 53 | PQueueType parts; |
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| 54 | int higain, oldgain, mincut, mindiff; |
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| 55 | |
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| 56 | nvtxs = graph->nvtxs; |
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| 57 | xadj = graph->xadj; |
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| 58 | vwgt = graph->vwgt; |
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| 59 | adjncy = graph->adjncy; |
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| 60 | adjwgt = graph->adjwgt; |
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| 61 | where = graph->where; |
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| 62 | id = graph->id; |
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| 63 | ed = graph->ed; |
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| 64 | pwgts = graph->pwgts; |
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| 65 | bndptr = graph->bndptr; |
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| 66 | bndind = graph->bndind; |
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| 67 | |
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| 68 | moved = idxwspacemalloc(ctrl, nvtxs); |
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| 69 | perm = idxwspacemalloc(ctrl, nvtxs); |
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| 70 | |
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| 71 | /* Determine from which domain you will be moving data */ |
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| 72 | mindiff = abs(tpwgts[0]-pwgts[0]); |
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| 73 | from = (pwgts[0] < tpwgts[0] ? 1 : 0); |
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| 74 | to = (from+1)%2; |
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| 75 | |
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| 76 | IFSET(ctrl->dbglvl, DBG_REFINE, |
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| 77 | printf("Partitions: [%6d %6d] T[%6d %6d], Nv-Nb[%6d %6d]. ICut: %6d [B]\n", |
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| 78 | pwgts[0], pwgts[1], tpwgts[0], tpwgts[1], graph->nvtxs, graph->nbnd, graph->mincut)); |
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| 79 | |
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| 80 | tmp = graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)]; |
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| 81 | PQueueInit(ctrl, &parts, nvtxs, tmp); |
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| 82 | |
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| 83 | idxset(nvtxs, -1, moved); |
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| 84 | |
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| 85 | ASSERT(ComputeCut(graph, where) == graph->mincut); |
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| 86 | ASSERT(CheckBnd(graph)); |
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| 87 | |
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| 88 | /* Insert the boundary nodes of the proper partition whose size is OK in the priority queue */ |
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| 89 | nbnd = graph->nbnd; |
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| 90 | RandomPermute(nbnd, perm, 1); |
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| 91 | for (ii=0; ii<nbnd; ii++) { |
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| 92 | i = perm[ii]; |
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| 93 | ASSERT(ed[bndind[i]] > 0 || id[bndind[i]] == 0); |
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| 94 | ASSERT(bndptr[bndind[i]] != -1); |
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| 95 | if (where[bndind[i]] == from && vwgt[bndind[i]] <= mindiff) |
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| 96 | PQueueInsert(&parts, bndind[i], ed[bndind[i]]-id[bndind[i]]); |
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| 97 | } |
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| 98 | |
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| 99 | mincut = graph->mincut; |
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| 100 | for (nswaps=0; nswaps<nvtxs; nswaps++) { |
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| 101 | if ((higain = PQueueGetMax(&parts)) == -1) |
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| 102 | break; |
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| 103 | ASSERT(bndptr[higain] != -1); |
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| 104 | |
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| 105 | if (pwgts[to]+vwgt[higain] > tpwgts[to]) |
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| 106 | break; |
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| 107 | |
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| 108 | mincut -= (ed[higain]-id[higain]); |
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| 109 | INC_DEC(pwgts[to], pwgts[from], vwgt[higain]); |
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| 110 | |
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| 111 | where[higain] = to; |
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| 112 | moved[higain] = nswaps; |
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| 113 | |
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| 114 | IFSET(ctrl->dbglvl, DBG_MOVEINFO, |
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| 115 | printf("Moved %6d from %d. [%3d %3d] %5d [%4d %4d]\n", higain, from, ed[higain]-id[higain], vwgt[higain], mincut, pwgts[0], pwgts[1])); |
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| 116 | |
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| 117 | /************************************************************** |
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| 118 | * Update the id[i]/ed[i] values of the affected nodes |
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| 119 | ***************************************************************/ |
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| 120 | SWAP(id[higain], ed[higain], tmp); |
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| 121 | if (ed[higain] == 0 && xadj[higain] < xadj[higain+1]) |
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| 122 | BNDDelete(nbnd, bndind, bndptr, higain); |
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| 123 | |
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| 124 | for (j=xadj[higain]; j<xadj[higain+1]; j++) { |
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| 125 | k = adjncy[j]; |
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| 126 | oldgain = ed[k]-id[k]; |
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| 127 | |
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| 128 | kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]); |
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| 129 | INC_DEC(id[k], ed[k], kwgt); |
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| 130 | |
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| 131 | /* Update its boundary information and queue position */ |
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| 132 | if (bndptr[k] != -1) { /* If k was a boundary vertex */ |
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| 133 | if (ed[k] == 0) { /* Not a boundary vertex any more */ |
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| 134 | BNDDelete(nbnd, bndind, bndptr, k); |
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| 135 | if (moved[k] == -1 && where[k] == from && vwgt[k] <= mindiff) /* Remove it if in the queues */ |
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| 136 | PQueueDelete(&parts, k, oldgain); |
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| 137 | } |
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| 138 | else { /* If it has not been moved, update its position in the queue */ |
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| 139 | if (moved[k] == -1 && where[k] == from && vwgt[k] <= mindiff) |
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| 140 | PQueueUpdate(&parts, k, oldgain, ed[k]-id[k]); |
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| 141 | } |
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| 142 | } |
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| 143 | else { |
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| 144 | if (ed[k] > 0) { /* It will now become a boundary vertex */ |
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| 145 | BNDInsert(nbnd, bndind, bndptr, k); |
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| 146 | if (moved[k] == -1 && where[k] == from && vwgt[k] <= mindiff) |
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| 147 | PQueueInsert(&parts, k, ed[k]-id[k]); |
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| 148 | } |
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| 149 | } |
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| 150 | } |
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| 151 | } |
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| 152 | |
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| 153 | IFSET(ctrl->dbglvl, DBG_REFINE, |
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| 154 | printf("\tMinimum cut: %6d, PWGTS: [%6d %6d], NBND: %6d\n", mincut, pwgts[0], pwgts[1], nbnd)); |
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| 155 | |
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| 156 | graph->mincut = mincut; |
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| 157 | graph->nbnd = nbnd; |
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| 158 | |
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| 159 | PQueueFree(ctrl, &parts); |
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| 160 | |
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| 161 | idxwspacefree(ctrl, nvtxs); |
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| 162 | idxwspacefree(ctrl, nvtxs); |
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| 163 | } |
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| 164 | |
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| 165 | |
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| 166 | /************************************************************************* |
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| 167 | * This function balances two partitions by moving the highest gain |
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| 168 | * (including negative gain) vertices to the other domain. |
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| 169 | * It is used only when tha unbalance is due to non contigous |
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| 170 | * subdomains. That is, the are no boundary vertices. |
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| 171 | * It moves vertices from the domain that is overweight to the one that |
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| 172 | * is underweight. |
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| 173 | **************************************************************************/ |
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| 174 | void General2WayBalance(CtrlType *ctrl, GraphType *graph, int *tpwgts) |
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| 175 | { |
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| 176 | int i, ii, j, k, kwgt, nvtxs, nbnd, nswaps, from, to, pass, me, tmp; |
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| 177 | idxtype *xadj, *vwgt, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind, *pwgts; |
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| 178 | idxtype *moved, *perm; |
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| 179 | PQueueType parts; |
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| 180 | int higain, oldgain, mincut, mindiff; |
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| 181 | |
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| 182 | nvtxs = graph->nvtxs; |
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| 183 | xadj = graph->xadj; |
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| 184 | vwgt = graph->vwgt; |
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| 185 | adjncy = graph->adjncy; |
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| 186 | adjwgt = graph->adjwgt; |
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| 187 | where = graph->where; |
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| 188 | id = graph->id; |
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| 189 | ed = graph->ed; |
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| 190 | pwgts = graph->pwgts; |
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| 191 | bndptr = graph->bndptr; |
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| 192 | bndind = graph->bndind; |
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| 193 | |
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| 194 | moved = idxwspacemalloc(ctrl, nvtxs); |
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| 195 | perm = idxwspacemalloc(ctrl, nvtxs); |
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| 196 | |
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| 197 | /* Determine from which domain you will be moving data */ |
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| 198 | mindiff = abs(tpwgts[0]-pwgts[0]); |
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| 199 | from = (pwgts[0] < tpwgts[0] ? 1 : 0); |
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| 200 | to = (from+1)%2; |
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| 201 | |
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| 202 | IFSET(ctrl->dbglvl, DBG_REFINE, |
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| 203 | printf("Partitions: [%6d %6d] T[%6d %6d], Nv-Nb[%6d %6d]. ICut: %6d [B]\n", |
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| 204 | pwgts[0], pwgts[1], tpwgts[0], tpwgts[1], graph->nvtxs, graph->nbnd, graph->mincut)); |
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| 205 | |
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| 206 | tmp = graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)]; |
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| 207 | PQueueInit(ctrl, &parts, nvtxs, tmp); |
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| 208 | |
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| 209 | idxset(nvtxs, -1, moved); |
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| 210 | |
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| 211 | ASSERT(ComputeCut(graph, where) == graph->mincut); |
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| 212 | ASSERT(CheckBnd(graph)); |
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| 213 | |
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| 214 | /* Insert the nodes of the proper partition whose size is OK in the priority queue */ |
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| 215 | RandomPermute(nvtxs, perm, 1); |
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| 216 | for (ii=0; ii<nvtxs; ii++) { |
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| 217 | i = perm[ii]; |
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| 218 | if (where[i] == from && vwgt[i] <= mindiff) |
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| 219 | PQueueInsert(&parts, i, ed[i]-id[i]); |
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| 220 | } |
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| 221 | |
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| 222 | mincut = graph->mincut; |
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| 223 | nbnd = graph->nbnd; |
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| 224 | for (nswaps=0; nswaps<nvtxs; nswaps++) { |
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| 225 | if ((higain = PQueueGetMax(&parts)) == -1) |
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| 226 | break; |
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| 227 | |
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| 228 | if (pwgts[to]+vwgt[higain] > tpwgts[to]) |
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| 229 | break; |
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| 230 | |
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| 231 | mincut -= (ed[higain]-id[higain]); |
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| 232 | INC_DEC(pwgts[to], pwgts[from], vwgt[higain]); |
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| 233 | |
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| 234 | where[higain] = to; |
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| 235 | moved[higain] = nswaps; |
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| 236 | |
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| 237 | IFSET(ctrl->dbglvl, DBG_MOVEINFO, |
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| 238 | printf("Moved %6d from %d. [%3d %3d] %5d [%4d %4d]\n", higain, from, ed[higain]-id[higain], vwgt[higain], mincut, pwgts[0], pwgts[1])); |
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| 239 | |
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| 240 | /************************************************************** |
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| 241 | * Update the id[i]/ed[i] values of the affected nodes |
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| 242 | ***************************************************************/ |
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| 243 | SWAP(id[higain], ed[higain], tmp); |
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| 244 | if (ed[higain] == 0 && bndptr[higain] != -1 && xadj[higain] < xadj[higain+1]) |
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| 245 | BNDDelete(nbnd, bndind, bndptr, higain); |
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| 246 | if (ed[higain] > 0 && bndptr[higain] == -1) |
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| 247 | BNDInsert(nbnd, bndind, bndptr, higain); |
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| 248 | |
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| 249 | for (j=xadj[higain]; j<xadj[higain+1]; j++) { |
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| 250 | k = adjncy[j]; |
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| 251 | oldgain = ed[k]-id[k]; |
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| 252 | |
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| 253 | kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]); |
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| 254 | INC_DEC(id[k], ed[k], kwgt); |
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| 255 | |
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| 256 | /* Update the queue position */ |
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| 257 | if (moved[k] == -1 && where[k] == from && vwgt[k] <= mindiff) |
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| 258 | PQueueUpdate(&parts, k, oldgain, ed[k]-id[k]); |
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| 259 | |
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| 260 | /* Update its boundary information */ |
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| 261 | if (ed[k] == 0 && bndptr[k] != -1) |
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| 262 | BNDDelete(nbnd, bndind, bndptr, k); |
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| 263 | else if (ed[k] > 0 && bndptr[k] == -1) |
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| 264 | BNDInsert(nbnd, bndind, bndptr, k); |
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| 265 | } |
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| 266 | } |
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| 267 | |
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| 268 | IFSET(ctrl->dbglvl, DBG_REFINE, |
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| 269 | printf("\tMinimum cut: %6d, PWGTS: [%6d %6d], NBND: %6d\n", mincut, pwgts[0], pwgts[1], nbnd)); |
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| 270 | |
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| 271 | graph->mincut = mincut; |
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| 272 | graph->nbnd = nbnd; |
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| 273 | |
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| 274 | PQueueFree(ctrl, &parts); |
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| 275 | |
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| 276 | idxwspacefree(ctrl, nvtxs); |
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| 277 | idxwspacefree(ctrl, nvtxs); |
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| 278 | } |
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