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fm.c
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1 /*
2  * Copyright 1997, Regents of the University of Minnesota
3  *
4  * fm.c
5  *
6  * This file contains code that implements the edge-based FM refinement
7  *
8  * Started 7/23/97
9  * George
10  *
11  * $Id: fm.c,v 1.1 1998/11/27 17:59:14 karypis Exp $
12  */
13 
14 #include <metis.h>
15 
16 
17 /*************************************************************************
18 * This function performs an edge-based FM refinement
19 **************************************************************************/
20 void FM_2WayEdgeRefine(CtrlType *ctrl, GraphType *graph, int *tpwgts, int npasses)
21 {
22  int i, ii, j, k, kwgt, nvtxs, nbnd, nswaps, from, to, pass, me, limit, tmp;
23  idxtype *xadj, *vwgt, *adjncy, *adjwgt, *where, *id, *ed, *bndptr, *bndind, *pwgts;
24  idxtype *moved, *swaps, *perm;
25  PQueueType parts[2];
26  int higain, oldgain, mincut, mindiff, origdiff, initcut, newcut, mincutorder, avgvwgt;
27 
28  nvtxs = graph->nvtxs;
29  xadj = graph->xadj;
30  vwgt = graph->vwgt;
31  adjncy = graph->adjncy;
32  adjwgt = graph->adjwgt;
33  where = graph->where;
34  id = graph->id;
35  ed = graph->ed;
36  pwgts = graph->pwgts;
37  bndptr = graph->bndptr;
38  bndind = graph->bndind;
39 
40  moved = idxwspacemalloc(ctrl, nvtxs);
41  swaps = idxwspacemalloc(ctrl, nvtxs);
42  perm = idxwspacemalloc(ctrl, nvtxs);
43 
44  limit = amin(amax(0.01*nvtxs, 15), 100);
45  avgvwgt = amin((pwgts[0]+pwgts[1])/20, 2*(pwgts[0]+pwgts[1])/nvtxs);
46 
47  tmp = graph->adjwgtsum[idxamax(nvtxs, graph->adjwgtsum)];
48  PQueueInit(ctrl, &parts[0], nvtxs, tmp);
49  PQueueInit(ctrl, &parts[1], nvtxs, tmp);
50 
51  IFSET(ctrl->dbglvl, DBG_REFINE,
52  printf("Partitions: [%6d %6d] T[%6d %6d], Nv-Nb[%6d %6d]. ICut: %6d\n",
53  pwgts[0], pwgts[1], tpwgts[0], tpwgts[1], graph->nvtxs, graph->nbnd, graph->mincut));
54 
55  origdiff = abs(tpwgts[0]-pwgts[0]);
56  idxset(nvtxs, -1, moved);
57  for (pass=0; pass<npasses; pass++) { /* Do a number of passes */
58  PQueueReset(&parts[0]);
59  PQueueReset(&parts[1]);
60 
61  mincutorder = -1;
62  newcut = mincut = initcut = graph->mincut;
63  mindiff = abs(tpwgts[0]-pwgts[0]);
64 
65  ASSERT(ComputeCut(graph, where) == graph->mincut);
66  ASSERT(CheckBnd(graph));
67 
68  /* Insert boundary nodes in the priority queues */
69  nbnd = graph->nbnd;
70  RandomPermute(nbnd, perm, 1);
71  for (ii=0; ii<nbnd; ii++) {
72  i = perm[ii];
73  ASSERT(ed[bndind[i]] > 0 || id[bndind[i]] == 0);
74  ASSERT(bndptr[bndind[i]] != -1);
75  PQueueInsert(&parts[where[bndind[i]]], bndind[i], ed[bndind[i]]-id[bndind[i]]);
76  }
77 
78  for (nswaps=0; nswaps<nvtxs; nswaps++) {
79  from = (tpwgts[0]-pwgts[0] < tpwgts[1]-pwgts[1] ? 0 : 1);
80  to = (from+1)%2;
81 
82  if ((higain = PQueueGetMax(&parts[from])) == -1)
83  break;
84  ASSERT(bndptr[higain] != -1);
85 
86  newcut -= (ed[higain]-id[higain]);
87  INC_DEC(pwgts[to], pwgts[from], vwgt[higain]);
88 
89  if ((newcut < mincut && abs(tpwgts[0]-pwgts[0]) <= origdiff+avgvwgt) ||
90  (newcut == mincut && abs(tpwgts[0]-pwgts[0]) < mindiff)) {
91  mincut = newcut;
92  mindiff = abs(tpwgts[0]-pwgts[0]);
93  mincutorder = nswaps;
94  }
95  else if (nswaps-mincutorder > limit) { /* We hit the limit, undo last move */
96  newcut += (ed[higain]-id[higain]);
97  INC_DEC(pwgts[from], pwgts[to], vwgt[higain]);
98  break;
99  }
100 
101  where[higain] = to;
102  moved[higain] = nswaps;
103  swaps[nswaps] = higain;
104 
105  IFSET(ctrl->dbglvl, DBG_MOVEINFO,
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]));
107 
108  /**************************************************************
109  * Update the id[i]/ed[i] values of the affected nodes
110  ***************************************************************/
111  SWAP(id[higain], ed[higain], tmp);
112  if (ed[higain] == 0 && xadj[higain] < xadj[higain+1])
113  BNDDelete(nbnd, bndind, bndptr, higain);
114 
115  for (j=xadj[higain]; j<xadj[higain+1]; j++) {
116  k = adjncy[j];
117  oldgain = ed[k]-id[k];
118 
119  kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]);
120  INC_DEC(id[k], ed[k], kwgt);
121 
122  /* Update its boundary information and queue position */
123  if (bndptr[k] != -1) { /* If k was a boundary vertex */
124  if (ed[k] == 0) { /* Not a boundary vertex any more */
125  BNDDelete(nbnd, bndind, bndptr, k);
126  if (moved[k] == -1) /* Remove it if in the queues */
127  PQueueDelete(&parts[where[k]], k, oldgain);
128  }
129  else { /* If it has not been moved, update its position in the queue */
130  if (moved[k] == -1)
131  PQueueUpdate(&parts[where[k]], k, oldgain, ed[k]-id[k]);
132  }
133  }
134  else {
135  if (ed[k] > 0) { /* It will now become a boundary vertex */
136  BNDInsert(nbnd, bndind, bndptr, k);
137  if (moved[k] == -1)
138  PQueueInsert(&parts[where[k]], k, ed[k]-id[k]);
139  }
140  }
141  }
142 
143  }
144 
145 
146  /****************************************************************
147  * Roll back computations
148  *****************************************************************/
149  for (i=0; i<nswaps; i++)
150  moved[swaps[i]] = -1; /* reset moved array */
151  for (nswaps--; nswaps>mincutorder; nswaps--) {
152  higain = swaps[nswaps];
153 
154  to = where[higain] = (where[higain]+1)%2;
155  SWAP(id[higain], ed[higain], tmp);
156  if (ed[higain] == 0 && bndptr[higain] != -1 && xadj[higain] < xadj[higain+1])
157  BNDDelete(nbnd, bndind, bndptr, higain);
158  else if (ed[higain] > 0 && bndptr[higain] == -1)
159  BNDInsert(nbnd, bndind, bndptr, higain);
160 
161  INC_DEC(pwgts[to], pwgts[(to+1)%2], vwgt[higain]);
162  for (j=xadj[higain]; j<xadj[higain+1]; j++) {
163  k = adjncy[j];
164 
165  kwgt = (to == where[k] ? adjwgt[j] : -adjwgt[j]);
166  INC_DEC(id[k], ed[k], kwgt);
167 
168  if (bndptr[k] != -1 && ed[k] == 0)
169  BNDDelete(nbnd, bndind, bndptr, k);
170  if (bndptr[k] == -1 && ed[k] > 0)
171  BNDInsert(nbnd, bndind, bndptr, k);
172  }
173  }
174 
175  IFSET(ctrl->dbglvl, DBG_REFINE,
176  printf("\tMinimum cut: %6d at %5d, PWGTS: [%6d %6d], NBND: %6d\n", mincut, mincutorder, pwgts[0], pwgts[1], nbnd));
177 
178  graph->mincut = mincut;
179  graph->nbnd = nbnd;
180 
181  if (mincutorder == -1 || mincut == initcut)
182  break;
183  }
184 
185  PQueueFree(ctrl, &parts[0]);
186  PQueueFree(ctrl, &parts[1]);
187 
188  idxwspacefree(ctrl, nvtxs);
189  idxwspacefree(ctrl, nvtxs);
190  idxwspacefree(ctrl, nvtxs);
191 
192 }
193 
194 
#define idxwspacefree
Definition: rename.h:165
#define PQueueUpdate
Definition: rename.h:320
idxtype * pwgts
Definition: struct.h:176
idxtype * adjwgtsum
Definition: struct.h:168
#define DBG_REFINE
Definition: defs.h:157
int nbnd
Definition: struct.h:177
idxtype * ed
Definition: struct.h:181
idxtype * id
Definition: struct.h:181
#define BNDInsert(nbnd, bndind, bndptr, vtx)
Definition: macros.h:102
int mincut
Definition: struct.h:175
#define DBG_MOVEINFO
Definition: defs.h:159
idxtype * bndptr
Definition: struct.h:178
#define idxwspacemalloc
Definition: rename.h:164
HitTile_Vector graph
idxtype * where
Definition: struct.h:176
int idxtype
Definition: struct.h:19
#define PQueueReset
Definition: rename.h:316
#define IFSET(a, flag, cmd)
Definition: macros.h:61
int dbglvl
Definition: struct.h:216
#define CheckBnd
Definition: rename.h:44
#define idxset
Definition: rename.h:390
idxtype * adjwgt
Definition: struct.h:166
#define BNDDelete(nbnd, bndind, bndptr, vtx)
Definition: macros.h:109
#define amax(a, b)
Definition: macros.h:29
idxtype * bndind
Definition: struct.h:178
#define idxamax
Definition: rename.h:393
#define FM_2WayEdgeRefine
Definition: rename.h:58
idxtype * vwgt
Definition: struct.h:163
#define INC_DEC(a, b, val)
Definition: macros.h:39
#define PQueueGetMax
Definition: rename.h:322
#define PQueueInsert
Definition: rename.h:318
int nvtxs
Definition: struct.h:161
#define RandomPermute
Definition: rename.h:410
#define ASSERT(expr)
Definition: macros.h:130
#define SWAP(a, b, tmp)
Definition: macros.h:36
#define ComputeCut
Definition: rename.h:43
#define PQueueDelete
Definition: rename.h:319
#define PQueueFree
Definition: rename.h:317
#define amin(a, b)
Definition: macros.h:30
idxtype * adjncy
Definition: struct.h:165
idxtype * xadj
Definition: struct.h:162
#define PQueueInit
Definition: rename.h:315