summaryrefslogtreecommitdiffstats
path: root/src/misc/extra/extraBddMisc.c
blob: a3320ad397b7ddfb1323a8e5b0c1aee6901a0d3b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
/**CFile****************************************************************

  FileName    [extraBddMisc.c]

  SystemName  [ABC: Logic synthesis and verification system.]

  PackageName [extra]

  Synopsis    [DD-based utilities.]

  Author      [Alan Mishchenko]
  
  Affiliation [UC Berkeley]

  Date        [Ver. 1.0. Started - June 20, 2005.]

  Revision    [$Id: extraBddMisc.c,v 1.4 2005/10/04 00:19:54 alanmi Exp $]

***********************************************************************/

#include "extra.h"

/*---------------------------------------------------------------------------*/
/* Constant declarations                                                     */
/*---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------*/
/* Stucture declarations                                                     */
/*---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------*/
/* Type declarations                                                         */
/*---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------*/
/* Variable declarations                                                     */
/*---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------*/
/* Macro declarations                                                        */
/*---------------------------------------------------------------------------*/


/**AutomaticStart*************************************************************/

/*---------------------------------------------------------------------------*/
/* Static function prototypes                                                */
/*---------------------------------------------------------------------------*/

// file "extraDdTransfer.c"
static DdNode * extraTransferPermuteRecur( DdManager * ddS, DdManager * ddD, DdNode * f, st_table * table, int * Permute );
static DdNode * extraTransferPermute( DdManager * ddS, DdManager * ddD, DdNode * f, int * Permute );
static DdNode * cuddBddPermuteRecur ARGS( ( DdManager * manager, DdHashTable * table, DdNode * node, int *permut ) );

// file "cuddUtils.c"
static void ddSupportStep(DdNode *f, int *support);
static void ddClearFlag(DdNode *f);

static DdNode* extraZddPrimes( DdManager *dd, DdNode* F );

/**AutomaticEnd***************************************************************/

/*---------------------------------------------------------------------------*/
/* Definition of exported functions                                          */
/*---------------------------------------------------------------------------*/

/**Function********************************************************************

  Synopsis    [Convert a {A,B}DD from a manager to another with variable remapping.]

  Description [Convert a {A,B}DD from a manager to another one. The orders of the
  variables in the two managers may be different. Returns a
  pointer to the {A,B}DD in the destination manager if successful; NULL
  otherwise. The i-th entry in the array Permute tells what is the index
  of the i-th variable from the old manager in the new manager.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode * Extra_TransferPermute( DdManager * ddSource, DdManager * ddDestination, DdNode * f, int * Permute )
{
    DdNode * bRes;
    do
    {
        ddDestination->reordered = 0;
        bRes = extraTransferPermute( ddSource, ddDestination, f, Permute );
    }
    while ( ddDestination->reordered == 1 );
    return ( bRes );

}                               /* end of Extra_TransferPermute */

/**Function********************************************************************

  Synopsis    [Transfers the BDD from one manager into another level by level.]

  Description [Transfers the BDD from one manager into another while
  preserving the correspondence between variables level by level.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode * Extra_TransferLevelByLevel( DdManager * ddSource, DdManager * ddDestination, DdNode * f )
{
    DdNode * bRes;
    int * pPermute;
    int nMin, nMax, i;

    nMin = ddMin(ddSource->size, ddDestination->size);
    nMax = ddMax(ddSource->size, ddDestination->size);
    pPermute = ALLOC( int, nMax );
    // set up the variable permutation
    for ( i = 0; i < nMin; i++ )
        pPermute[ ddSource->invperm[i] ] = ddDestination->invperm[i];
    if ( ddSource->size > ddDestination->size )
    {
        for (      ; i < nMax; i++ )
            pPermute[ ddSource->invperm[i] ] = -1;
    }
    bRes = Extra_TransferPermute( ddSource, ddDestination, f, pPermute );
    FREE( pPermute );
    return bRes;
}

/**Function********************************************************************

  Synopsis    [Remaps the function to depend on the topmost variables on the manager.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode * Extra_bddRemapUp(
  DdManager * dd,
  DdNode * bF )
{
    int * pPermute;
    DdNode * bSupp, * bTemp, * bRes;
    int Counter;

    pPermute = ALLOC( int, dd->size );

    // get support
    bSupp = Cudd_Support( dd, bF );    Cudd_Ref( bSupp );

    // create the variable map
    // to remap the DD into the upper part of the manager
    Counter = 0;
    for ( bTemp = bSupp; bTemp != dd->one; bTemp = cuddT(bTemp) )
        pPermute[bTemp->index] = dd->invperm[Counter++];

    // transfer the BDD and remap it
    bRes = Cudd_bddPermute( dd, bF, pPermute );  Cudd_Ref( bRes );

    // remove support
    Cudd_RecursiveDeref( dd, bSupp );

    // return
    Cudd_Deref( bRes );
    free( pPermute );
    return bRes;
}

/**Function********************************************************************

  Synopsis    [Moves the BDD by the given number of variables up or down.]

  Description []

  SideEffects []

  SeeAlso     [Extra_bddShift]

******************************************************************************/
DdNode * Extra_bddMove( 
  DdManager * dd,   /* the DD manager */
  DdNode * bF,
  int nVars) 
{
    DdNode * res;
    DdNode * bVars;
    if ( nVars == 0 )
        return bF;
    if ( Cudd_IsConstant(bF) )
        return bF;
    assert( nVars <= dd->size );
    if ( nVars > 0 )
        bVars = dd->vars[nVars];
    else
        bVars = Cudd_Not(dd->vars[-nVars]);

    do {
        dd->reordered = 0;
        res = extraBddMove( dd, bF, bVars );
    } while (dd->reordered == 1);
    return(res);

} /* end of Extra_bddMove */

/**Function*************************************************************

  Synopsis    []

  Description []

  SideEffects []

  SeeAlso     []

***********************************************************************/
void Extra_StopManager( DdManager * dd )
{
    int RetValue;
    // check for remaining references in the package
    RetValue = Cudd_CheckZeroRef( dd );
    if ( RetValue > 0 )
        printf( "\nThe number of referenced nodes = %d\n\n", RetValue );
//  Cudd_PrintInfo( dd, stdout );
    Cudd_Quit( dd );
}

/**Function********************************************************************

  Synopsis    [Outputs the BDD in a readable format.]

  Description []

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
void Extra_bddPrint( DdManager * dd, DdNode * F )
{
    DdGen * Gen;
    int * Cube;
    CUDD_VALUE_TYPE Value;
    int nVars = dd->size;
    int fFirstCube = 1;
    int i;

    if ( F == NULL )
    {
        printf("NULL");
        return;
    }
    if ( F == b0 )
    {
        printf("Constant 0");
        return;
    }
    if ( F == b1 )
    {
        printf("Constant 1");
        return;
    }

    Cudd_ForeachCube( dd, F, Gen, Cube, Value )
    {
        if ( fFirstCube )
            fFirstCube = 0;
        else
//          Output << " + ";
            printf( " + " );

        for ( i = 0; i < nVars; i++ )
            if ( Cube[i] == 0 )
                printf( "[%d]'", i );
//              printf( "%c'", (char)('a'+i) );
            else if ( Cube[i] == 1 )
                printf( "[%d]", i );
//              printf( "%c", (char)('a'+i) );
    }

//  printf("\n");
}
/**Function********************************************************************

  Synopsis    [Returns the size of the support.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Extra_bddSuppSize( DdManager * dd, DdNode * bSupp )
{
    int Counter = 0;
    while ( bSupp != b1 )
    {
        assert( !Cudd_IsComplement(bSupp) );
        assert( cuddE(bSupp) == b0 );

        bSupp = cuddT(bSupp);
        Counter++;
    }
    return Counter;
}

/**Function********************************************************************

  Synopsis    [Returns 1 if the support contains the given BDD variable.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Extra_bddSuppContainVar( DdManager * dd, DdNode * bS, DdNode * bVar )   
{ 
    for( ; bS != b1; bS = cuddT(bS) )
        if ( bS->index == bVar->index )
            return 1;
    return 0;
}

/**Function********************************************************************

  Synopsis    [Returns 1 if two supports represented as BDD cubes are overlapping.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Extra_bddSuppOverlapping( DdManager * dd, DdNode * S1, DdNode * S2 )
{
    while ( S1->index != CUDD_CONST_INDEX && S2->index != CUDD_CONST_INDEX )
    {
        // if the top vars are the same, they intersect
        if ( S1->index == S2->index )
            return 1;
        // if the top vars are different, skip the one, which is higher
        if ( dd->perm[S1->index] < dd->perm[S2->index] )
            S1 = cuddT(S1);
        else
            S2 = cuddT(S2);
    }
    return 0;
}

/**Function********************************************************************

  Synopsis    [Returns the number of different vars in two supports.]

  Description [Counts the number of variables that appear in one support and 
  does not appear in other support. If the number exceeds DiffMax, returns DiffMax.]

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Extra_bddSuppDifferentVars( DdManager * dd, DdNode * S1, DdNode * S2, int DiffMax )
{
    int Result = 0;
    while ( S1->index != CUDD_CONST_INDEX && S2->index != CUDD_CONST_INDEX )
    {
        // if the top vars are the same, this var is the same
        if ( S1->index == S2->index )
        {
            S1 = cuddT(S1);
            S2 = cuddT(S2);
            continue;
        }
        // the top var is different
        Result++;

        if ( Result >= DiffMax )
            return DiffMax;

        // if the top vars are different, skip the one, which is higher
        if ( dd->perm[S1->index] < dd->perm[S2->index] )
            S1 = cuddT(S1);
        else
            S2 = cuddT(S2);
    }

    // consider the remaining variables
    if ( S1->index != CUDD_CONST_INDEX )
        Result += Extra_bddSuppSize(dd,S1);
    else if ( S2->index != CUDD_CONST_INDEX )
        Result += Extra_bddSuppSize(dd,S2);

    if ( Result >= DiffMax )
        return DiffMax;
    return Result;
}


/**Function********************************************************************

  Synopsis    [Checks the support containment.]

  Description [This function returns 1 if one support is contained in another.
  In this case, bLarge (bSmall) is assigned to point to the larger (smaller) support.
  If the supports are identical, return 0 and does not assign the supports!]

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Extra_bddSuppCheckContainment( DdManager * dd, DdNode * bL, DdNode * bH, DdNode ** bLarge, DdNode ** bSmall )
{
    DdNode * bSL = bL;
    DdNode * bSH = bH;
    int fLcontainsH = 1;
    int fHcontainsL = 1;
    int TopVar;
    
    if ( bSL == bSH )
        return 0;

    while ( bSL != b1 || bSH != b1 )
    {
        if ( bSL == b1 )
        { // Low component has no vars; High components has some vars
            fLcontainsH = 0;
            if ( fHcontainsL == 0 )
                return 0;
            else
                break;
        }

        if ( bSH == b1 )
        { // similarly
            fHcontainsL = 0;
            if ( fLcontainsH == 0 )
                return 0;
            else
                break;
        }

        // determine the topmost var of the supports by comparing their levels
        if ( dd->perm[bSL->index] < dd->perm[bSH->index] )
            TopVar = bSL->index;
        else
            TopVar = bSH->index;

        if ( TopVar == bSL->index && TopVar == bSH->index ) 
        { // they are on the same level
            // it does not tell us anything about their containment
            // skip this var
            bSL = cuddT(bSL);
            bSH = cuddT(bSH);
        }
        else if ( TopVar == bSL->index ) // and TopVar != bSH->index
        { // Low components is higher and contains more vars
            // it is not possible that High component contains Low
            fHcontainsL = 0;
            // skip this var
            bSL = cuddT(bSL);
        }
        else // if ( TopVar == bSH->index ) // and TopVar != bSL->index
        { // similarly
            fLcontainsH = 0;
            // skip this var
            bSH = cuddT(bSH);
        }

        // check the stopping condition
        if ( !fHcontainsL && !fLcontainsH )
            return 0;
    }
    // only one of them can be true at the same time
    assert( !fHcontainsL || !fLcontainsH );
    if ( fHcontainsL )
    {
        *bLarge = bH;
        *bSmall = bL;
    }
    else // fLcontainsH
    {
        *bLarge = bL;
        *bSmall = bH;
    }
    return 1;
}


/**Function********************************************************************

  Synopsis    [Finds variables on which the DD depends and returns them as am array.]

  Description [Finds the variables on which the DD depends. Returns an array 
  with entries set to 1 for those variables that belong to the support; 
  NULL otherwise. The array is allocated by the user and should have at least
  as many entries as the maximum number of variables in BDD and ZDD parts of 
  the manager.]

  SideEffects [None]

  SeeAlso     [Cudd_Support Cudd_VectorSupport Cudd_ClassifySupport]

******************************************************************************/
int * 
Extra_SupportArray(
  DdManager * dd, /* manager */
  DdNode * f,     /* DD whose support is sought */
  int * support ) /* array allocated by the user */
{
    int i, size;

    /* Initialize support array for ddSupportStep. */
    size = ddMax(dd->size, dd->sizeZ);
    for (i = 0; i < size; i++) 
        support[i] = 0;
    
    /* Compute support and clean up markers. */
    ddSupportStep(Cudd_Regular(f),support);
    ddClearFlag(Cudd_Regular(f));

    return(support);

} /* end of Extra_SupportArray */

/**Function********************************************************************

  Synopsis    [Finds the variables on which a set of DDs depends.]

  Description [Finds the variables on which a set of DDs depends.
  The set must contain either BDDs and ADDs, or ZDDs.
  Returns a BDD consisting of the product of the variables if
  successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     [Cudd_Support Cudd_ClassifySupport]

******************************************************************************/
int *
Extra_VectorSupportArray( 
  DdManager * dd, /* manager */ 
  DdNode ** F, /* array of DDs whose support is sought */ 
  int n, /* size of the array */  
  int * support ) /* array allocated by the user */
{
    int i, size;

    /* Allocate and initialize support array for ddSupportStep. */
    size = ddMax( dd->size, dd->sizeZ );
    for ( i = 0; i < size; i++ )
        support[i] = 0;

    /* Compute support and clean up markers. */
    for ( i = 0; i < n; i++ )
        ddSupportStep( Cudd_Regular(F[i]), support );
    for ( i = 0; i < n; i++ )
        ddClearFlag( Cudd_Regular(F[i]) );

    return support;
}

/**Function********************************************************************

  Synopsis    [Find any cube belonging to the on-set of the function.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode *  Extra_bddFindOneCube( DdManager * dd, DdNode * bF )
{
    char * s_Temp;
    DdNode * bCube, * bTemp;
    int v;

    // get the vector of variables in the cube
    s_Temp = ALLOC( char, dd->size );
    Cudd_bddPickOneCube( dd, bF, s_Temp );

    // start the cube
    bCube = b1; Cudd_Ref( bCube );
    for ( v = 0; v < dd->size; v++ )
        if ( s_Temp[v] == 0 )
        {
//          Cube &= !s_XVars[v];
            bCube = Cudd_bddAnd( dd, bTemp = bCube, Cudd_Not(dd->vars[v]) ); Cudd_Ref( bCube );
            Cudd_RecursiveDeref( dd, bTemp );
        }
        else if ( s_Temp[v] == 1 )
        {
//          Cube &=  s_XVars[v];
            bCube = Cudd_bddAnd( dd, bTemp = bCube,          dd->vars[v]  ); Cudd_Ref( bCube );
            Cudd_RecursiveDeref( dd, bTemp );
        }
    Cudd_Deref(bCube);
    free( s_Temp );
    return bCube;
}

/**Function********************************************************************

  Synopsis    [Returns one cube contained in the given BDD.]

  Description [This function returns the cube with the smallest 
  bits-to-integer value.]

  SideEffects []

******************************************************************************/
DdNode * Extra_bddGetOneCube( DdManager * dd, DdNode * bFunc )
{
    DdNode * bFuncR, * bFunc0, * bFunc1;
    DdNode * bRes0,  * bRes1,  * bRes;

    bFuncR = Cudd_Regular(bFunc);
    if ( cuddIsConstant(bFuncR) )
        return bFunc;

    // cofactor
    if ( Cudd_IsComplement(bFunc) )
    {
        bFunc0 = Cudd_Not( cuddE(bFuncR) );
        bFunc1 = Cudd_Not( cuddT(bFuncR) );
    }
    else
    {
        bFunc0 = cuddE(bFuncR);
        bFunc1 = cuddT(bFuncR);
    }

    // try to find the cube with the negative literal
    bRes0 = Extra_bddGetOneCube( dd, bFunc0 );  Cudd_Ref( bRes0 );

    if ( bRes0 != b0 )
    {
        bRes = Cudd_bddAnd( dd, bRes0, Cudd_Not(dd->vars[bFuncR->index]) ); Cudd_Ref( bRes );
        Cudd_RecursiveDeref( dd, bRes0 );
    }
    else
    {
        Cudd_RecursiveDeref( dd, bRes0 );
        // try to find the cube with the positive literal
        bRes1 = Extra_bddGetOneCube( dd, bFunc1 );  Cudd_Ref( bRes1 );
        assert( bRes1 != b0 );
        bRes = Cudd_bddAnd( dd, bRes1, dd->vars[bFuncR->index] ); Cudd_Ref( bRes );
        Cudd_RecursiveDeref( dd, bRes1 );
    }

    Cudd_Deref( bRes );
    return bRes;
}

/**Function********************************************************************

  Synopsis    [Performs the reordering-sensitive step of Extra_bddMove().]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode * Extra_bddComputeRangeCube( DdManager * dd, int iStart, int iStop )
{
    DdNode * bTemp, * bProd;
    int i;
    assert( iStart <= iStop );
    assert( iStart >= 0 && iStart <= dd->size );
    assert( iStop >= 0  && iStop  <= dd->size );
    bProd = b1;         Cudd_Ref( bProd );
    for ( i = iStart; i < iStop; i++ )
    {
        bProd = Cudd_bddAnd( dd, bTemp = bProd, dd->vars[i] );      Cudd_Ref( bProd );
        Cudd_RecursiveDeref( dd, bTemp ); 
    }
    Cudd_Deref( bProd );
    return bProd;
}

/**Function********************************************************************

  Synopsis    [Computes the cube of BDD variables corresponding to bits it the bit-code]

  Description [Returns a bdd composed of elementary bdds found in array BddVars[] such 
  that the bdd vars encode the number Value of bit length CodeWidth (if fMsbFirst is 1, 
  the most significant bit is encoded with the first bdd variable). If the variables 
  BddVars are not specified, takes the first CodeWidth variables of the manager]

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode * Extra_bddBitsToCube( DdManager * dd, int Code, int CodeWidth, DdNode ** pbVars, int fMsbFirst )
{
    int z;
    DdNode * bTemp, * bVar, * bVarBdd, * bResult;

    bResult = b1;   Cudd_Ref( bResult );
    for ( z = 0; z < CodeWidth; z++ )
    {
        bVarBdd = (pbVars)? pbVars[z]: dd->vars[z];
        if ( fMsbFirst )
            bVar = Cudd_NotCond( bVarBdd, (Code & (1 << (CodeWidth-1-z)))==0 );
        else
            bVar = Cudd_NotCond( bVarBdd, (Code & (1 << (z)))==0 );
        bResult = Cudd_bddAnd( dd, bTemp = bResult, bVar );     Cudd_Ref( bResult );
        Cudd_RecursiveDeref( dd, bTemp );
    }
    Cudd_Deref( bResult );

    return bResult;
}  /* end of Extra_bddBitsToCube */

/**Function********************************************************************

  Synopsis    [Finds the support as a negative polarity cube.]

  Description [Finds the variables on which a DD depends. Returns a BDD 
  consisting of the product of the variables in the negative polarity 
  if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     [Cudd_VectorSupport Cudd_Support]

******************************************************************************/
DdNode * Extra_bddSupportNegativeCube( DdManager * dd, DdNode * f )
{
    int *support;
    DdNode *res, *tmp, *var;
    int i, j;
    int size;

    /* Allocate and initialize support array for ddSupportStep. */
    size = ddMax( dd->size, dd->sizeZ );
    support = ALLOC( int, size );
    if ( support == NULL )
    {
        dd->errorCode = CUDD_MEMORY_OUT;
        return ( NULL );
    }
    for ( i = 0; i < size; i++ )
    {
        support[i] = 0;
    }

    /* Compute support and clean up markers. */
    ddSupportStep( Cudd_Regular( f ), support );
    ddClearFlag( Cudd_Regular( f ) );

    /* Transform support from array to cube. */
    do
    {
        dd->reordered = 0;
        res = DD_ONE( dd );
        cuddRef( res );
        for ( j = size - 1; j >= 0; j-- )
        {                        /* for each level bottom-up */
            i = ( j >= dd->size ) ? j : dd->invperm[j];
            if ( support[i] == 1 )
            {
                var = cuddUniqueInter( dd, i, dd->one, Cudd_Not( dd->one ) );
                //////////////////////////////////////////////////////////////////
                var = Cudd_Not(var);
                //////////////////////////////////////////////////////////////////
                cuddRef( var );
                tmp = cuddBddAndRecur( dd, res, var );
                if ( tmp == NULL )
                {
                    Cudd_RecursiveDeref( dd, res );
                    Cudd_RecursiveDeref( dd, var );
                    res = NULL;
                    break;
                }
                cuddRef( tmp );
                Cudd_RecursiveDeref( dd, res );
                Cudd_RecursiveDeref( dd, var );
                res = tmp;
            }
        }
    }
    while ( dd->reordered == 1 );

    FREE( support );
    if ( res != NULL )
        cuddDeref( res );
    return ( res );

}                                /* end of Extra_SupportNeg */

/**Function********************************************************************

  Synopsis    [Returns 1 if the BDD is the BDD of elementary variable.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Extra_bddIsVar( DdNode * bFunc )
{
    bFunc = Cudd_Regular( bFunc );
    if ( cuddIsConstant(bFunc) )
        return 0;
    return cuddIsConstant( cuddT(bFunc) ) && cuddIsConstant( Cudd_Regular(cuddE(bFunc)) );
}

/**Function********************************************************************

  Synopsis    [Creates AND composed of the first nVars of the manager.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode * Extra_bddCreateAnd( DdManager * dd, int nVars )
{
    DdNode * bFunc, * bTemp;
    int i;
    bFunc = Cudd_ReadOne(dd); Cudd_Ref( bFunc );
    for ( i = 0; i < nVars; i++ )
    {
        bFunc = Cudd_bddAnd( dd, bTemp = bFunc, Cudd_bddIthVar(dd,i) );  Cudd_Ref( bFunc );
        Cudd_RecursiveDeref( dd, bTemp );
    }
    Cudd_Deref( bFunc );
    return bFunc;
}

/**Function********************************************************************

  Synopsis    [Creates OR composed of the first nVars of the manager.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode * Extra_bddCreateOr( DdManager * dd, int nVars )
{
    DdNode * bFunc, * bTemp;
    int i;
    bFunc = Cudd_ReadLogicZero(dd); Cudd_Ref( bFunc );
    for ( i = 0; i < nVars; i++ )
    {
        bFunc = Cudd_bddOr( dd, bTemp = bFunc, Cudd_bddIthVar(dd,i) );  Cudd_Ref( bFunc );
        Cudd_RecursiveDeref( dd, bTemp );
    }
    Cudd_Deref( bFunc );
    return bFunc;
}

/**Function********************************************************************

  Synopsis    [Creates EXOR composed of the first nVars of the manager.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode * Extra_bddCreateExor( DdManager * dd, int nVars )
{
    DdNode * bFunc, * bTemp;
    int i;
    bFunc = Cudd_ReadLogicZero(dd); Cudd_Ref( bFunc );
    for ( i = 0; i < nVars; i++ )
    {
        bFunc = Cudd_bddXor( dd, bTemp = bFunc, Cudd_bddIthVar(dd,i) );  Cudd_Ref( bFunc );
        Cudd_RecursiveDeref( dd, bTemp );
    }
    Cudd_Deref( bFunc );
    return bFunc;
}

/**Function********************************************************************

  Synopsis    [Computes the set of primes as a ZDD.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode * Extra_zddPrimes( DdManager * dd, DdNode * F )
{
    DdNode    *res;
    do {
        dd->reordered = 0;
        res = extraZddPrimes(dd, F);
        if ( dd->reordered == 1 )
            printf("\nReordering in Extra_zddPrimes()\n");
    } while (dd->reordered == 1);
    return(res);

} /* end of Extra_zddPrimes */

/**Function********************************************************************

  Synopsis    [Permutes the variables of the array of BDDs.]

  Description [Given a permutation in array permut, creates a new BDD
  with permuted variables. There should be an entry in array permut
  for each variable in the manager. The i-th entry of permut holds the
  index of the variable that is to substitute the i-th variable.
  The DDs in the resulting array are already referenced.]

  SideEffects [None]

  SeeAlso     [Cudd_addPermute Cudd_bddSwapVariables]

******************************************************************************/
void Extra_bddPermuteArray( DdManager * manager, DdNode ** bNodesIn, DdNode ** bNodesOut, int nNodes, int *permut )
{
    DdHashTable *table;
    int i, k;
    do
    {
        manager->reordered = 0;
        table = cuddHashTableInit( manager, 1, 2 );

        /* permute the output functions one-by-one */
        for ( i = 0; i < nNodes; i++ )
        {
            bNodesOut[i] = cuddBddPermuteRecur( manager, table, bNodesIn[i], permut );
            if ( bNodesOut[i] == NULL )
            {
                /* deref the array of the already computed outputs */
                for ( k = 0; k < i; k++ )
                    Cudd_RecursiveDeref( manager, bNodesOut[k] );
                break;
            }
            cuddRef( bNodesOut[i] );
        }
        /* Dispose of local cache. */
        cuddHashTableQuit( table );
    }
    while ( manager->reordered == 1 );
}    /* end of Extra_bddPermuteArray */


/*---------------------------------------------------------------------------*/
/* Definition of internal functions                                          */
/*---------------------------------------------------------------------------*/

/**Function********************************************************************

  Synopsis    [Performs the reordering-sensitive step of Extra_bddMove().]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode * extraBddMove( 
  DdManager * dd,    /* the DD manager */
  DdNode * bF,
  DdNode * bDist) 
{
    DdNode * bRes;

    if ( Cudd_IsConstant(bF) )
        return bF;

    if ( bRes = cuddCacheLookup2(dd, extraBddMove, bF, bDist) )
        return bRes;
    else
    {
        DdNode * bRes0, * bRes1;             
        DdNode * bF0, * bF1;             
        DdNode * bFR = Cudd_Regular(bF); 
        int VarNew;
        
        if ( Cudd_IsComplement(bDist) )
            VarNew = bFR->index - Cudd_Not(bDist)->index;
        else
            VarNew = bFR->index + bDist->index;
        assert( VarNew < dd->size );

        // cofactor the functions
        if ( bFR != bF ) // bFunc is complemented 
        {
            bF0 = Cudd_Not( cuddE(bFR) );
            bF1 = Cudd_Not( cuddT(bFR) );
        }
        else
        {
            bF0 = cuddE(bFR);
            bF1 = cuddT(bFR);
        }

        bRes0 = extraBddMove( dd, bF0, bDist );
        if ( bRes0 == NULL ) 
            return NULL;
        cuddRef( bRes0 );

        bRes1 = extraBddMove( dd, bF1, bDist );
        if ( bRes1 == NULL ) 
        {
            Cudd_RecursiveDeref( dd, bRes0 );
            return NULL;
        }
        cuddRef( bRes1 );

        /* only bRes0 and bRes1 are referenced at this point */
        bRes = cuddBddIteRecur( dd, dd->vars[VarNew], bRes1, bRes0 );
        if ( bRes == NULL ) 
        {
            Cudd_RecursiveDeref( dd, bRes0 );
            Cudd_RecursiveDeref( dd, bRes1 );
            return NULL;
        }
        cuddRef( bRes );
        Cudd_RecursiveDeref( dd, bRes0 );
        Cudd_RecursiveDeref( dd, bRes1 );

        /* insert the result into cache */
        cuddCacheInsert2( dd, extraBddMove, bF, bDist, bRes );
        cuddDeref( bRes );
        return bRes;
    }
} /* end of extraBddMove */


/**Function********************************************************************

  Synopsis    [Finds three cofactors of the cover w.r.t. to the topmost variable.]

  Description [Finds three cofactors of the cover w.r.t. to the topmost variable.
  Does not check the cover for being a constant. Assumes that ZDD variables encoding 
  positive and negative polarities are adjacent in the variable order. Is different 
  from cuddZddGetCofactors3() in that it does not compute the cofactors w.r.t. the 
  given variable but takes the cofactors with respent to the topmost variable. 
  This function is more efficient when used in recursive procedures because it does 
  not require referencing of the resulting cofactors (compare cuddZddProduct() 
  and extraZddPrimeProduct()).]

  SideEffects [None]

  SeeAlso     [cuddZddGetCofactors3]

******************************************************************************/
void 
extraDecomposeCover( 
  DdManager* dd,    /* the manager */
  DdNode*  zC,      /* the cover */
  DdNode** zC0,     /* the pointer to the negative var cofactor */ 
  DdNode** zC1,     /* the pointer to the positive var cofactor */ 
  DdNode** zC2 )    /* the pointer to the cofactor without var */ 
{
    if ( (zC->index & 1) == 0 ) 
    { /* the top variable is present in positive polarity and maybe in negative */

        DdNode *Temp = cuddE( zC );
        *zC1  = cuddT( zC );
        if ( cuddIZ(dd,Temp->index) == cuddIZ(dd,zC->index) + 1 )
        {   /* Temp is not a terminal node 
             * top var is present in negative polarity */
            *zC2 = cuddE( Temp );
            *zC0 = cuddT( Temp );
        }
        else
        {   /* top var is not present in negative polarity */
            *zC2 = Temp;
            *zC0 = dd->zero;
        }
    }
    else 
    { /* the top variable is present only in negative */
        *zC1 = dd->zero;
        *zC2 = cuddE( zC );
        *zC0 = cuddT( zC );
    }
} /* extraDecomposeCover */

/*---------------------------------------------------------------------------*/
/* Definition of static Functions                                            */
/*---------------------------------------------------------------------------*/

/**Function********************************************************************

  Synopsis    [Convert a BDD from a manager to another one.]

  Description [Convert a BDD from a manager to another one. Returns a
  pointer to the BDD in the destination manager if successful; NULL
  otherwise.]

  SideEffects [None]

  SeeAlso     [Extra_TransferPermute]

******************************************************************************/
DdNode * extraTransferPermute( DdManager * ddS, DdManager * ddD, DdNode * f, int * Permute )
{
    DdNode *res;
    st_table *table = NULL;
    st_generator *gen = NULL;
    DdNode *key, *value;

    table = st_init_table( st_ptrcmp, st_ptrhash );
    if ( table == NULL )
        goto failure;
    res = extraTransferPermuteRecur( ddS, ddD, f, table, Permute );
    if ( res != NULL )
        cuddRef( res );

    /* Dereference all elements in the table and dispose of the table.
       ** This must be done also if res is NULL to avoid leaks in case of
       ** reordering. */
    gen = st_init_gen( table );
    if ( gen == NULL )
        goto failure;
    while ( st_gen( gen, ( char ** ) &key, ( char ** ) &value ) )
    {
        Cudd_RecursiveDeref( ddD, value );
    }
    st_free_gen( gen );
    gen = NULL;
    st_free_table( table );
    table = NULL;

    if ( res != NULL )
        cuddDeref( res );
    return ( res );

  failure:
    if ( table != NULL )
        st_free_table( table );
    if ( gen != NULL )
        st_free_gen( gen );
    return ( NULL );

}                               /* end of extraTransferPermute */


/**Function********************************************************************

  Synopsis    [Performs the recursive step of Extra_TransferPermute.]

  Description [Performs the recursive step of Extra_TransferPermute.
  Returns a pointer to the result if successful; NULL otherwise.]

  SideEffects [None]

  SeeAlso     [extraTransferPermute]

******************************************************************************/
static DdNode * 
extraTransferPermuteRecur( 
  DdManager * ddS, 
  DdManager * ddD, 
  DdNode * f, 
  st_table * table, 
  int * Permute )
{
    DdNode *ft, *fe, *t, *e, *var, *res;
    DdNode *one, *zero;
    int index;
    int comple = 0;

    statLine( ddD );
    one = DD_ONE( ddD );
    comple = Cudd_IsComplement( f );

    /* Trivial cases. */
    if ( Cudd_IsConstant( f ) )
        return ( Cudd_NotCond( one, comple ) );


    /* Make canonical to increase the utilization of the cache. */
    f = Cudd_NotCond( f, comple );
    /* Now f is a regular pointer to a non-constant node. */

    /* Check the cache. */
    if ( st_lookup( table, ( char * ) f, ( char ** ) &res ) )
        return ( Cudd_NotCond( res, comple ) );

    /* Recursive step. */
    if ( Permute )
        index = Permute[f->index];
    else
        index = f->index;

    ft = cuddT( f );
    fe = cuddE( f );

    t = extraTransferPermuteRecur( ddS, ddD, ft, table, Permute );
    if ( t == NULL )
    {
        return ( NULL );
    }
    cuddRef( t );

    e = extraTransferPermuteRecur( ddS, ddD, fe, table, Permute );
    if ( e == NULL )
    {
        Cudd_RecursiveDeref( ddD, t );
        return ( NULL );
    }
    cuddRef( e );

    zero = Cudd_Not(ddD->one);
    var = cuddUniqueInter( ddD, index, one, zero );
    if ( var == NULL )
    {
        Cudd_RecursiveDeref( ddD, t );
        Cudd_RecursiveDeref( ddD, e );
        return ( NULL );
    }
    res = cuddBddIteRecur( ddD, var, t, e );

    if ( res == NULL )
    {
        Cudd_RecursiveDeref( ddD, t );
        Cudd_RecursiveDeref( ddD, e );
        return ( NULL );
    }
    cuddRef( res );
    Cudd_RecursiveDeref( ddD, t );
    Cudd_RecursiveDeref( ddD, e );

    if ( st_add_direct( table, ( char * ) f, ( char * ) res ) ==
         ST_OUT_OF_MEM )
    {
        Cudd_RecursiveDeref( ddD, res );
        return ( NULL );
    }
    return ( Cudd_NotCond( res, comple ) );

}                               /* end of extraTransferPermuteRecur */

/**Function********************************************************************

  Synopsis    [Performs the recursive step of Cudd_Support.]

  Description [Performs the recursive step of Cudd_Support. Performs a
  DFS from f. The support is accumulated in supp as a side effect. Uses
  the LSB of the then pointer as visited flag.]

  SideEffects [None]

  SeeAlso     [ddClearFlag]

******************************************************************************/
static void
ddSupportStep(
  DdNode * f,
  int * support)
{
    if (cuddIsConstant(f) || Cudd_IsComplement(f->next)) {
    return;
    }

    support[f->index] = 1;
    ddSupportStep(cuddT(f),support);
    ddSupportStep(Cudd_Regular(cuddE(f)),support);
    /* Mark as visited. */
    f->next = Cudd_Not(f->next);
    return;

} /* end of ddSupportStep */


/**Function********************************************************************

  Synopsis    [Performs a DFS from f, clearing the LSB of the next
  pointers.]

  Description []

  SideEffects [None]

  SeeAlso     [ddSupportStep ddDagInt]

******************************************************************************/
static void
ddClearFlag(
  DdNode * f)
{
    if (!Cudd_IsComplement(f->next)) {
    return;
    }
    /* Clear visited flag. */
    f->next = Cudd_Regular(f->next);
    if (cuddIsConstant(f)) {
    return;
    }
    ddClearFlag(cuddT(f));
    ddClearFlag(Cudd_Regular(cuddE(f)));
    return;

} /* end of ddClearFlag */


/**Function********************************************************************

  Synopsis    [Composed three subcovers into one ZDD.]

  Description []

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
DdNode *
extraComposeCover( 
  DdManager* dd,    /* the manager */
  DdNode* zC0,     /* the pointer to the negative var cofactor */ 
  DdNode* zC1,     /* the pointer to the positive var cofactor */ 
  DdNode* zC2,     /* the pointer to the cofactor without var */ 
  int TopVar)    /* the index of the positive ZDD var */
{
    DdNode * zRes, * zTemp;
    /* compose with-neg-var and without-var using the neg ZDD var */
    zTemp = cuddZddGetNode( dd, 2*TopVar + 1, zC0, zC2 );
    if ( zTemp == NULL ) 
    {
        Cudd_RecursiveDerefZdd(dd, zC0);
        Cudd_RecursiveDerefZdd(dd, zC1);
        Cudd_RecursiveDerefZdd(dd, zC2);
        return NULL;
    }
    cuddRef( zTemp );
    cuddDeref( zC0 );
    cuddDeref( zC2 );

    /* compose with-pos-var and previous result using the pos ZDD var */
    zRes = cuddZddGetNode( dd, 2*TopVar, zC1, zTemp );
    if ( zRes == NULL ) 
    {
        Cudd_RecursiveDerefZdd(dd, zC1);
        Cudd_RecursiveDerefZdd(dd, zTemp);
        return NULL;
    }
    cuddDeref( zC1 );
    cuddDeref( zTemp );
    return zRes;
} /* extraComposeCover */

/**Function********************************************************************

  Synopsis    [Performs the recursive step of prime computation.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
DdNode* extraZddPrimes( DdManager *dd, DdNode* F )
{
    DdNode *zRes;

    if ( F == Cudd_Not( dd->one ) )
        return dd->zero;
    if ( F == dd->one )
        return dd->one;

    /* check cache */
    zRes = cuddCacheLookup1Zdd(dd, extraZddPrimes, F);
    if (zRes)
        return(zRes);
    {
        /* temporary variables */
        DdNode *bF01, *zP0, *zP1;
        /* three components of the prime set */
        DdNode *zResE, *zResP, *zResN;
        int fIsComp = Cudd_IsComplement( F );

        /* find cofactors of F */
        DdNode * bF0 = Cudd_NotCond( Cudd_E( F ), fIsComp );
        DdNode * bF1 = Cudd_NotCond( Cudd_T( F ), fIsComp );

        /* find the intersection of cofactors */
        bF01 = cuddBddAndRecur( dd, bF0, bF1 );
        if ( bF01 == NULL ) return NULL;
        cuddRef( bF01 );

        /* solve the problems for cofactors */
        zP0 = extraZddPrimes( dd, bF0 );
        if ( zP0 == NULL )
        {
            Cudd_RecursiveDeref( dd, bF01 );
            return NULL;
        }
        cuddRef( zP0 );

        zP1 = extraZddPrimes( dd, bF1 );
        if ( zP1 == NULL )
        {
            Cudd_RecursiveDeref( dd, bF01 );
            Cudd_RecursiveDerefZdd( dd, zP0 );
            return NULL;
        }
        cuddRef( zP1 );

        /* check for local unateness */
        if ( bF01 == bF0 )       /* unate increasing */
        {
            /* intersection is useless */
            cuddDeref( bF01 );
            /* the primes of intersection are the primes of F0 */
            zResE = zP0;
            /* there are no primes with negative var */
            zResN = dd->zero;
            cuddRef( zResN );
            /* primes with positive var are primes of F1 that are not primes of F01 */
            zResP = cuddZddDiff( dd, zP1, zP0 );
            if ( zResP == NULL )  
            {
                Cudd_RecursiveDerefZdd( dd, zResE );
                Cudd_RecursiveDerefZdd( dd, zResN );
                Cudd_RecursiveDerefZdd( dd, zP1 );
                return NULL;
            }
            cuddRef( zResP );
            Cudd_RecursiveDerefZdd( dd, zP1 );
        }
        else if ( bF01 == bF1 ) /* unate decreasing */
        {
            /* intersection is useless */
            cuddDeref( bF01 );
            /* the primes of intersection are the primes of F1 */
            zResE = zP1;
            /* there are no primes with positive var */
            zResP = dd->zero;
            cuddRef( zResP );
            /* primes with negative var are primes of F0 that are not primes of F01 */
            zResN = cuddZddDiff( dd, zP0, zP1 );
            if ( zResN == NULL )  
            {
                Cudd_RecursiveDerefZdd( dd, zResE );
                Cudd_RecursiveDerefZdd( dd, zResP );
                Cudd_RecursiveDerefZdd( dd, zP0 );
                return NULL;
            }
            cuddRef( zResN );
            Cudd_RecursiveDerefZdd( dd, zP0 );
        }
        else /* not unate */
        {
            /* primes without the top var are primes of F10 */
            zResE = extraZddPrimes( dd, bF01 );
            if ( zResE == NULL )  
            {
                Cudd_RecursiveDerefZdd( dd, bF01 );
                Cudd_RecursiveDerefZdd( dd, zP0 );
                Cudd_RecursiveDerefZdd( dd, zP1 );
                return NULL;
            }
            cuddRef( zResE );
            Cudd_RecursiveDeref( dd, bF01 );

            /* primes with the negative top var are those of P0 that are not in F10 */
            zResN = cuddZddDiff( dd, zP0, zResE );
            if ( zResN == NULL )  
            {
                Cudd_RecursiveDerefZdd( dd, zResE );
                Cudd_RecursiveDerefZdd( dd, zP0 );
                Cudd_RecursiveDerefZdd( dd, zP1 );
                return NULL;
            }
            cuddRef( zResN );
            Cudd_RecursiveDerefZdd( dd, zP0 );

            /* primes with the positive top var are those of P1 that are not in F10 */
            zResP = cuddZddDiff( dd, zP1, zResE );
            if ( zResP == NULL )  
            {
                Cudd_RecursiveDerefZdd( dd, zResE );
                Cudd_RecursiveDerefZdd( dd, zResN );
                Cudd_RecursiveDerefZdd( dd, zP1 );
                return NULL;
            }
            cuddRef( zResP );
            Cudd_RecursiveDerefZdd( dd, zP1 );
        }

        zRes = extraComposeCover( dd, zResN, zResP, zResE, Cudd_Regular(F)->index );
        if ( zRes == NULL ) return NULL;

        /* insert the result into cache */
        cuddCacheInsert1(dd, extraZddPrimes, F, zRes);
        return zRes;
    }
} /* end of extraZddPrimes */

/**Function********************************************************************

  Synopsis    [Implements the recursive step of Cudd_bddPermute.]

  Description [ Recursively puts the BDD in the order given in the array permut.
  Checks for trivial cases to terminate recursion, then splits on the
  children of this node.  Once the solutions for the children are
  obtained, it puts into the current position the node from the rest of
  the BDD that should be here. Then returns this BDD.
  The key here is that the node being visited is NOT put in its proper
  place by this instance, but rather is switched when its proper position
  is reached in the recursion tree.<p>
  The DdNode * that is returned is the same BDD as passed in as node,
  but in the new order.]

  SideEffects [None]

  SeeAlso     [Cudd_bddPermute cuddAddPermuteRecur]

******************************************************************************/
static DdNode *
cuddBddPermuteRecur( DdManager * manager /* DD manager */ ,
                     DdHashTable * table /* computed table */ ,
                     DdNode * node /* BDD to be reordered */ ,
                     int *permut /* permutation array */  )
{
    DdNode *N, *T, *E;
    DdNode *res;
    int index;

    statLine( manager );
    N = Cudd_Regular( node );

    /* Check for terminal case of constant node. */
    if ( cuddIsConstant( N ) )
    {
        return ( node );
    }

    /* If problem already solved, look up answer and return. */
    if ( N->ref != 1 && ( res = cuddHashTableLookup1( table, N ) ) != NULL )
    {
#ifdef DD_DEBUG
        bddPermuteRecurHits++;
#endif
        return ( Cudd_NotCond( res, N != node ) );
    }

    /* Split and recur on children of this node. */
    T = cuddBddPermuteRecur( manager, table, cuddT( N ), permut );
    if ( T == NULL )
        return ( NULL );
    cuddRef( T );
    E = cuddBddPermuteRecur( manager, table, cuddE( N ), permut );
    if ( E == NULL )
    {
        Cudd_IterDerefBdd( manager, T );
        return ( NULL );
    }
    cuddRef( E );

    /* Move variable that should be in this position to this position
       ** by retrieving the single var BDD for that variable, and calling
       ** cuddBddIteRecur with the T and E we just created.
     */
    index = permut[N->index];
    res = cuddBddIteRecur( manager, manager->vars[index], T, E );
    if ( res == NULL )
    {
        Cudd_IterDerefBdd( manager, T );
        Cudd_IterDerefBdd( manager, E );
        return ( NULL );
    }
    cuddRef( res );
    Cudd_IterDerefBdd( manager, T );
    Cudd_IterDerefBdd( manager, E );

    /* Do not keep the result if the reference count is only 1, since
       ** it will not be visited again.
     */
    if ( N->ref != 1 )
    {
        ptrint fanout = ( ptrint ) N->ref;
        cuddSatDec( fanout );
        if ( !cuddHashTableInsert1( table, N, res, fanout ) )
        {
            Cudd_IterDerefBdd( manager, res );
            return ( NULL );
        }
    }
    cuddDeref( res );
    return ( Cudd_NotCond( res, N != node ) );

}                                /* end of cuddBddPermuteRecur */


////////////////////////////////////////////////////////////////////////
///                       END OF FILE                                ///
////////////////////////////////////////////////////////////////////////