summaryrefslogtreecommitdiffstats
path: root/src/aig/kit/cloud.c
blob: dc57e2b728e9773adede50f64c538bafcc5f4cc8 (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
/**CFile****************************************************************

  FileName    [cloudCore.c]

  PackageName [Fast application-specific BDD package.]

  Synopsis    [The package core.]

  Author      [Alan Mishchenko <alanmi@ece.pdx.edu>]
  
  Affiliation [ECE Department. Portland State University, Portland, Oregon.]

  Date        [Ver. 1.0. Started - June 10, 2002.]

  Revision    [$Id: cloudCore.c,v 1.0 2002/06/10 03:00:00 alanmi Exp $]

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

#include "cloud.h"

// the number of operators using cache
static int CacheOperNum = 4;

// the ratio of cache size to the unique table size for each operator
static int CacheLogRatioDefault[4] = {
    2, // CLOUD_OPER_AND, 
    8, // CLOUD_OPER_XOR, 
    8, // CLOUD_OPER_BDIFF, 
    8  // CLOUD_OPER_LEQ 
};

// the ratio of cache size to the unique table size for each operator
static int CacheSize[4] = {
    2, // CLOUD_OPER_AND, 
    2, // CLOUD_OPER_XOR, 
    2, // CLOUD_OPER_BDIFF, 
    2  // CLOUD_OPER_LEQ 
};

////////////////////////////////////////////////////////////////////////
///                       FUNCTION DECLARATIONS                      ///
////////////////////////////////////////////////////////////////////////

// static functions
static CloudNode * cloudMakeNode( CloudManager * dd, CloudVar v, CloudNode * t, CloudNode * e );
static void        cloudCacheAllocate( CloudManager * dd, CloudOper oper );

////////////////////////////////////////////////////////////////////////
///                       FUNCTION DEFINITIONS                       ///
////////////////////////////////////////////////////////////////////////

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

  Synopsis    [Starts the cloud manager.]

  Description [The first arguments is the number of elementary variables used.
  The second arguments is the number of bits of the unsigned integer used to 
  represent nodes in the unique table. If the second argument is 0, the package 
  assumes 23 to represent nodes, which is equivalent to 2^23 = 8,388,608 nodes.]
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
CloudManager * Cloud_Init( int nVars, int nBits )
{
    CloudManager * dd;
    int i;
    int clk1, clk2;

    assert( nVars <= 100000 );
    assert( nBits < 32 );

    // assign the defaults
    if ( nBits == 0 )
        nBits = CLOUD_NODE_BITS;

    // start the manager
    dd = ABC_CALLOC( CloudManager, 1 );
    dd->nMemUsed          += sizeof(CloudManager);

    // variables
    dd->nVars             = nVars;              // the number of variables allocated
    // bits
    dd->bitsNode          = nBits;              // the number of bits used for the node
    for ( i = 0; i < CacheOperNum; i++ )
        dd->bitsCache[i]  = nBits - CacheLogRatioDefault[i];
    // shifts
    dd->shiftUnique       = 8*sizeof(unsigned) - (nBits + 1); // gets node index in the hash table
    for ( i = 0; i < CacheOperNum; i++ )
        dd->shiftCache[i] = 8*sizeof(unsigned) - dd->bitsCache[i];
    // nodes
    dd->nNodesAlloc       = (1 << (nBits + 1)); // 2 ^ (nBits + 1)
    dd->nNodesLimit       = (1 << nBits);       // 2 ^  nBits

    // unique table
clk1 = clock();
    dd->tUnique           = ABC_CALLOC( CloudNode, dd->nNodesAlloc );
    dd->nMemUsed         += sizeof(CloudNode) * dd->nNodesAlloc;
clk2 = clock();
//ABC_PRT( "calloc() time", clk2 - clk1 ); 

    // set up the constant node (the only node that is not in the hash table)
    dd->nSignCur          = 1;
    dd->tUnique[0].s      = dd->nSignCur;
    dd->tUnique[0].v      = CLOUD_CONST_INDEX;
    dd->tUnique[0].e      = NULL;
    dd->tUnique[0].t      = NULL;
    dd->one               = dd->tUnique;
    dd->zero              = Cloud_Not(dd->one);
    dd->nNodesCur         = 1;

    // special nodes
    dd->pNodeStart        = dd->tUnique + 1;
    dd->pNodeEnd          = dd->tUnique + dd->nNodesAlloc;

    // set up the elementary variables
    dd->vars              = ABC_ALLOC( CloudNode *, dd->nVars );
    dd->nMemUsed         += sizeof(CloudNode *) * dd->nVars;
    for ( i = 0; i < dd->nVars; i++ )
        dd->vars[i]   = cloudMakeNode( dd, i, dd->one, dd->zero );

    return dd;
};

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

  Synopsis    [Stops the cloud manager.]

  Description [The first arguments tells show many elementary variables are used.
  The second arguments tells how many bits of the unsigned integer are used
  to represent regular nodes in the unique table.]
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
void Cloud_Quit( CloudManager * dd )
{
    int i;
    ABC_FREE( dd->ppNodes );
    ABC_FREE( dd->tUnique ); 
    ABC_FREE( dd->vars ); 
    for ( i = 0; i < 4; i++ )
        ABC_FREE( dd->tCaches[i] );
    ABC_FREE( dd ); 
}

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

  Synopsis    [Prepares the manager for another run.]

  Description []
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
void Cloud_Restart( CloudManager * dd )
{
    int i;
    assert( dd->one->s == dd->nSignCur );
    dd->nSignCur++;
    dd->one->s++;
    for ( i = 0; i < dd->nVars; i++ )
        dd->vars[i]->s++;
    dd->nNodesCur = 1 + dd->nVars;
}

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

  Synopsis    [This optional function allocates operation cache of the given size.]

  Description [Cache for each operation is allocated independently when the first 
  operation of the given type is performed. The user can allocate cache of his/her 
  preferred size by calling Cloud_CacheAllocate before the first operation of the 
  given type is performed, but this call is optional. Argument "logratio" gives
  the binary logarithm of the ratio of the size of the unique table to that of cache.
  For example, if "logratio" is equal to 3, and the unique table will be 2^3=8 times
  larger than cache; so, if unique table is 2^23 = 8,388,608 nodes, the cache size 
  will be 2^3=8 times smaller and equal to 2^20 = 1,048,576 entries.]
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
void Cloud_CacheAllocate( CloudManager * dd, CloudOper oper, int logratio )
{
    assert( logratio > 0 );            // cache cannot be larger than the unique table 
    assert( logratio < dd->bitsNode ); // cache cannot be smaller than 2 entries

    if ( logratio )
    {
        dd->bitsCache[oper]  = dd->bitsNode - logratio;
        dd->shiftCache[oper] = 8*sizeof(unsigned) - dd->bitsCache[oper];
    }
    cloudCacheAllocate( dd, oper );
}

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

  Synopsis    [Internal cache allocation.]

  Description []
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
void cloudCacheAllocate( CloudManager * dd, CloudOper oper )
{
    int nCacheEntries = (1 << dd->bitsCache[oper]);

    if ( CacheSize[oper] == 1 )
    {
        dd->tCaches[oper] = (CloudCacheEntry2 *)ABC_CALLOC( CloudCacheEntry1, nCacheEntries );
        dd->nMemUsed     += sizeof(CloudCacheEntry1) * nCacheEntries;
    }
    else if ( CacheSize[oper] == 2 )
    {
        dd->tCaches[oper] = (CloudCacheEntry2 *)ABC_CALLOC( CloudCacheEntry2, nCacheEntries );
        dd->nMemUsed     += sizeof(CloudCacheEntry2) * nCacheEntries;
    }
    else if ( CacheSize[oper] == 3 )
    {
        dd->tCaches[oper] = (CloudCacheEntry2 *)ABC_CALLOC( CloudCacheEntry3, nCacheEntries );
        dd->nMemUsed     += sizeof(CloudCacheEntry3) * nCacheEntries;
    }
}



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

  Synopsis    [Returns or creates a new node]

  Description [Checks the unique table for the existance of the node. If the node is 
  present, returns the node. If the node is absent, creates a new node.]
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
CloudNode * Cloud_MakeNode( CloudManager * dd, CloudVar v, CloudNode * t, CloudNode * e )
{
    CloudNode * pRes;
    CLOUD_ASSERT(t); 
    CLOUD_ASSERT(e);
    assert( v < Cloud_V(t) && v < Cloud_V(e) );       // variable should be above in the order
    if ( Cloud_IsComplement(t) )
    {
        pRes = cloudMakeNode( dd, v, Cloud_Not(t), Cloud_Not(e) );
        if ( pRes != NULL )
            pRes = Cloud_Not(pRes);            
    }
    else
        pRes = cloudMakeNode( dd, v, t, e );
    return pRes;
}

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

  Synopsis    [Returns or creates a new node]

  Description [Checks the unique table for the existance of the node. If the node is 
  present, returns the node. If the node is absent, creates a new node.]
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
CloudNode * cloudMakeNode( CloudManager * dd, CloudVar v, CloudNode * t, CloudNode * e )
{
    CloudNode * entryUnique;

    CLOUD_ASSERT(t); 
    CLOUD_ASSERT(e);

    assert( ((int)v) >= 0 && ((int)v) < dd->nVars );  // the variable must be in the range
    assert( v < Cloud_V(t) && v < Cloud_V(e) );       // variable should be above in the order
    assert( !Cloud_IsComplement(t) );                 // the THEN edge must not be complemented

    // make sure we are not searching for the constant node
    assert( t && e );

    // get the unique entry
    entryUnique = dd->tUnique + cloudHashCudd3(v, t, e, dd->shiftUnique);
    while ( entryUnique->s == dd->nSignCur )
    {
        // compare the node
        if ( entryUnique->v == v && entryUnique->t == t && entryUnique->e == e )
        { // the node is found
            dd->nUniqueHits++;
            return entryUnique;  // returns the node
        }
        // increment the hash value modulus the hash table size
        if ( ++entryUnique - dd->tUnique == dd->nNodesAlloc )
            entryUnique = dd->tUnique + 1;
        // increment the number of steps through the table
        dd->nUniqueSteps++;
    }
    dd->nUniqueMisses++;

    // check if the new node can be created
    if ( ++dd->nNodesCur == dd->nNodesLimit ) 
    { // initiate the restart
        printf( "Cloud needs restart!\n" );
//        fflush( stdout );
//        exit(1);
        return NULL;
    }
    // create the node
    entryUnique->s   = dd->nSignCur;
    entryUnique->v   = v;
    entryUnique->t   = t;
    entryUnique->e   = e;
    return entryUnique;  // returns the node
}


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

  Synopsis    [Performs the AND or two BDDs]

  Description []
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
CloudNode * cloudBddAnd( CloudManager * dd, CloudNode * f, CloudNode * g )
{
    CloudNode * F, * G, * r;
    CloudCacheEntry2 * cacheEntry;
    CloudNode * fv, * fnv, * gv, * gnv, * t, * e;
    CloudVar  var;

    assert( f <= g );

    // terminal cases
    F = Cloud_Regular(f);
    G = Cloud_Regular(g);
    if ( F == G )
    {
        if ( f == g )
            return f;
        else
            return dd->zero;
    }
    if ( F == dd->one )
    {
        if ( f == dd->one )
            return g;
        else
            return f;
    }

    // check cache
    cacheEntry = dd->tCaches[CLOUD_OPER_AND] + cloudHashCudd2(f, g, dd->shiftCache[CLOUD_OPER_AND]);
//    cacheEntry = dd->tCaches[CLOUD_OPER_AND] + cloudHashBuddy2(f, g, dd->shiftCache[CLOUD_OPER_AND]);
    r = cloudCacheLookup2( cacheEntry, dd->nSignCur, f, g );
    if ( r != NULL )
    {
        dd->nCacheHits++;
        return r;
    }
    dd->nCacheMisses++;


    // compute cofactors
    if ( cloudV(F) <= cloudV(G) )
    {
        var = cloudV(F);
        if ( Cloud_IsComplement(f) )
        {
            fnv = Cloud_Not(cloudE(F));
            fv  = Cloud_Not(cloudT(F));
        }
        else
        {
            fnv = cloudE(F);
            fv  = cloudT(F);
        }
    }
    else
    {
        var = cloudV(G);
        fv  = fnv = f;
    }

    if ( cloudV(G) <= cloudV(F) )
    {
        if ( Cloud_IsComplement(g) )
        {
            gnv = Cloud_Not(cloudE(G));
            gv  = Cloud_Not(cloudT(G));
        }
        else
        {
            gnv = cloudE(G);
            gv  = cloudT(G);
        }
    }
    else
    {
        gv = gnv = g;
    }

    if ( fv <= gv )
        t = cloudBddAnd( dd, fv, gv );
    else
        t = cloudBddAnd( dd, gv, fv );

    if ( t == NULL )
        return NULL;

    if ( fnv <= gnv )
        e = cloudBddAnd( dd, fnv, gnv );
    else
        e = cloudBddAnd( dd, gnv, fnv );

    if ( e == NULL )
        return NULL;

    if ( t == e )
        r = t;
    else
    {
        if ( Cloud_IsComplement(t) )
        {
            r = cloudMakeNode( dd, var, Cloud_Not(t), Cloud_Not(e) );
            if ( r == NULL )
                return NULL;
            r = Cloud_Not(r);
        }
        else
        {
            r = cloudMakeNode( dd, var, t, e );
            if ( r == NULL )
                return NULL;
        }
    }
    cloudCacheInsert2( cacheEntry, dd->nSignCur, f, g, r );
    return r;
}

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

  Synopsis    [Performs the AND or two BDDs]

  Description []
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
static inline CloudNode * cloudBddAnd_gate( CloudManager * dd, CloudNode * f, CloudNode * g )
{
    if ( f <= g )
        return cloudBddAnd(dd,f,g);
    else
        return cloudBddAnd(dd,g,f);
}

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

  Synopsis    [Performs the AND or two BDDs]

  Description []
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
CloudNode * Cloud_bddAnd( CloudManager * dd, CloudNode * f, CloudNode * g )
{
    if ( Cloud_Regular(f) == NULL || Cloud_Regular(g) == NULL )
        return NULL;
    CLOUD_ASSERT(f);
    CLOUD_ASSERT(g);
    if ( dd->tCaches[CLOUD_OPER_AND] == NULL )
        cloudCacheAllocate( dd, CLOUD_OPER_AND );
    return cloudBddAnd_gate( dd, f, g );
}

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

  Synopsis    [Performs the OR or two BDDs]

  Description []
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
CloudNode * Cloud_bddOr( CloudManager * dd, CloudNode * f, CloudNode * g )
{
    CloudNode * res;
    if ( Cloud_Regular(f) == NULL || Cloud_Regular(g) == NULL )
        return NULL;
    CLOUD_ASSERT(f);
    CLOUD_ASSERT(g);
    if ( dd->tCaches[CLOUD_OPER_AND] == NULL )
        cloudCacheAllocate( dd, CLOUD_OPER_AND );
    res = cloudBddAnd_gate( dd, Cloud_Not(f), Cloud_Not(g) );
    res = Cloud_NotCond( res, res != NULL );
    return res;
}

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

  Synopsis    [Performs the XOR or two BDDs]

  Description []
               
  SideEffects []

  SeeAlso     []

******************************************************************************/
CloudNode * Cloud_bddXor( CloudManager * dd, CloudNode * f, CloudNode * g )
{
    CloudNode * t0, * t1, * r;
    if ( Cloud_Regular(f) == NULL || Cloud_Regular(g) == NULL )
        return NULL;
    CLOUD_ASSERT(f);
    CLOUD_ASSERT(g);
    if ( dd->tCaches[CLOUD_OPER_AND] == NULL )
        cloudCacheAllocate( dd, CLOUD_OPER_AND );
    t0 = cloudBddAnd_gate( dd, f, Cloud_Not(g) );
    if ( t0 == NULL )
        return NULL;
    t1 = cloudBddAnd_gate( dd, Cloud_Not(f), g );
    if ( t1 == NULL )
        return NULL;
    r  = Cloud_bddOr( dd, t0, t1 );
    return r;
}



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

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

  Description []

  SideEffects [None]

  SeeAlso     [cloudSupport cloudDagSize]

******************************************************************************/
static void cloudClearMark( CloudManager * dd, CloudNode * n )
{
    if ( !cloudNodeIsMarked(n) )
        return;
    // clear visited flag
    cloudNodeUnmark(n);
    if ( cloudIsConstant(n) )
        return;
    cloudClearMark( dd, cloudT(n) );
    cloudClearMark( dd, Cloud_Regular(cloudE(n)) );
}

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

  Synopsis    [Performs the recursive step of Cloud_Support.]

  Description [Performs the recursive step of Cloud_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     []

******************************************************************************/
static void cloudSupport( CloudManager * dd, CloudNode * n, int * support )
{
    if ( cloudIsConstant(n) || cloudNodeIsMarked(n) )
        return;
    // set visited flag
    cloudNodeMark(n);
    support[cloudV(n)] = 1;
    cloudSupport( dd, cloudT(n), support );
    cloudSupport( dd, Cloud_Regular(cloudE(n)), support );
}

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

  Synopsis    [Finds the variables on which a DD depends.]

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

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
CloudNode * Cloud_Support( CloudManager * dd, CloudNode * n )
{
    CloudNode * res;
    int * support, i;

    CLOUD_ASSERT(n);

    // allocate and initialize support array for cloudSupport
    support = ABC_CALLOC( int, dd->nVars );

    // compute support and clean up markers
    cloudSupport( dd, Cloud_Regular(n), support );
    cloudClearMark( dd, Cloud_Regular(n) );

    // transform support from array to cube
    res = dd->one;
    for ( i = dd->nVars - 1; i >= 0; i-- ) // for each level bottom-up 
        if ( support[i] == 1 )
        {
            res = Cloud_bddAnd( dd, res, dd->vars[i] );
            if ( res == NULL )
                break;
        }
    ABC_FREE( support );
    return res;
}

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

  Synopsis    [Counts the variables on which a DD depends.]

  Description [Counts the variables on which a DD depends.
  Returns the number of the variables if successful; Cloud_OUT_OF_MEM
  otherwise.]

  SideEffects [None]

  SeeAlso     []

******************************************************************************/
int Cloud_SupportSize( CloudManager * dd, CloudNode * n )
{
    int * support, i, count;

    CLOUD_ASSERT(n);

    // allocate and initialize support array for cloudSupport
    support = ABC_CALLOC( int, dd->nVars );

    // compute support and clean up markers
    cloudSupport( dd, Cloud_Regular(n), support );
    cloudClearMark( dd, Cloud_Regular(n) );

    // count support variables
    count = 0;
    for ( i = 0; i < dd->nVars; i++ )
    {
        if ( support[i] == 1 )
            count++;
    }

    ABC_FREE( support );
    return count;
}


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

  Synopsis    [Performs the recursive step of Cloud_DagSize.]

  Description [Performs the recursive step of Cloud_DagSize. Returns the
  number of nodes in the graph rooted at n.]

  SideEffects [None]

******************************************************************************/
static int cloudDagSize( CloudManager * dd, CloudNode * n )
{
    int tval, eval;
    if ( cloudNodeIsMarked(n) )
        return 0;
    // set visited flag
    cloudNodeMark(n);
    if ( cloudIsConstant(n) )
        return 1;
    tval = cloudDagSize( dd, cloudT(n) );
    eval = cloudDagSize( dd, Cloud_Regular(cloudE(n)) );
    return tval + eval + 1;

}

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

  Synopsis    [Counts the number of nodes in a DD.]

  Description [Counts the number of nodes in a DD. Returns the number
  of nodes in the graph rooted at node.]

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Cloud_DagSize( CloudManager * dd, CloudNode * n )
{
    int res;
    res = cloudDagSize( dd, Cloud_Regular( n ) );
    cloudClearMark( dd, Cloud_Regular( n ) );
    return res;

}


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

  Synopsis    [Performs the recursive step of Cloud_DagSize.]

  Description [Performs the recursive step of Cloud_DagSize. Returns the
  number of nodes in the graph rooted at n.]

  SideEffects [None]

******************************************************************************/
static int Cloud_DagCollect_rec( CloudManager * dd, CloudNode * n, int * pCounter )
{
    int tval, eval;
    if ( cloudNodeIsMarked(n) )
        return 0;
    // set visited flag
    cloudNodeMark(n);
    if ( cloudIsConstant(n) )
    {
        dd->ppNodes[(*pCounter)++] = n;
        return 1;
    }
    tval = Cloud_DagCollect_rec( dd, cloudT(n), pCounter );
    eval = Cloud_DagCollect_rec( dd, Cloud_Regular(cloudE(n)), pCounter );
    dd->ppNodes[(*pCounter)++] = n;
    return tval + eval + 1;

}

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

  Synopsis    [Counts the number of nodes in a DD.]

  Description [Counts the number of nodes in a DD. Returns the number
  of nodes in the graph rooted at node.]

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Cloud_DagCollect( CloudManager * dd, CloudNode * n )
{
    int res, Counter = 0;
    if ( dd->ppNodes == NULL )
        dd->ppNodes = ABC_ALLOC( CloudNode *, dd->nNodesLimit );
    res = Cloud_DagCollect_rec( dd, Cloud_Regular( n ), &Counter );
    cloudClearMark( dd, Cloud_Regular( n ) );
    assert( res == Counter );
    return res;

}

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

  Synopsis    [Counts the number of nodes in an array of DDs.]

  Description [Counts the number of nodes in a DD. Returns the number
  of nodes in the graph rooted at node.]

  SideEffects []

  SeeAlso     []

******************************************************************************/
int Cloud_SharingSize( CloudManager * dd, CloudNode ** pn, int nn )
{
    int res, i;
    res = 0;
    for ( i = 0; i < nn; i++ )
        res += cloudDagSize( dd, Cloud_Regular( pn[i] ) );
    for ( i = 0; i < nn; i++ )
        cloudClearMark( dd, Cloud_Regular( pn[i] ) );
    return res;
}


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

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

  Description []

  SideEffects []

******************************************************************************/
CloudNode * Cloud_GetOneCube( CloudManager * dd, CloudNode * bFunc )
{
    CloudNode * bFunc0, * bFunc1, * res;

    if ( Cloud_IsConstant(bFunc) )
        return bFunc;

    // cofactor
    if ( Cloud_IsComplement(bFunc) )
    {
        bFunc0 = Cloud_Not( cloudE(bFunc) );
        bFunc1 = Cloud_Not( cloudT(bFunc) );
    }
    else
    {
        bFunc0 = cloudE(bFunc);
        bFunc1 = cloudT(bFunc);
    }

    // try to find the cube with the negative literal
    res = Cloud_GetOneCube( dd, bFunc0 );
    if ( res == NULL )
        return NULL;

    if ( res != dd->zero )
    {
        res = Cloud_bddAnd( dd, res, Cloud_Not(dd->vars[Cloud_V(bFunc)]) );
    }
    else
    {
        // try to find the cube with the positive literal
        res = Cloud_GetOneCube( dd, bFunc1 );
        if ( res == NULL )
            return NULL;
        assert( res != dd->zero );
        res = Cloud_bddAnd( dd, res, dd->vars[Cloud_V(bFunc)] );
    }
    return res;
}

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

  Synopsis    [Prints the BDD as a set of disjoint cubes to the standard output.]

  Description []

  SideEffects []

******************************************************************************/
void Cloud_bddPrint( CloudManager * dd, CloudNode * Func )
{
    CloudNode * Cube;
    int fFirst = 1;

    if ( Func == dd->zero )
        printf( "Constant 0." );
    else if ( Func == dd->one )
        printf( "Constant 1." );
    else
    {
        while ( 1 )
        {
            Cube = Cloud_GetOneCube( dd, Func );
            if ( Cube == NULL || Cube == dd->zero )
                break;
            if ( fFirst )       fFirst = 0;
            else                printf( " + " );
            Cloud_bddPrintCube( dd, Cube );
            Func = Cloud_bddAnd( dd, Func, Cloud_Not(Cube) );
        } 
    }
    printf( "\n" );
}

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

  Synopsis    [Prints one cube.]

  Description []

  SideEffects []

******************************************************************************/
void Cloud_bddPrintCube( CloudManager * dd, CloudNode * bCube )
{
    CloudNode * bCube0, * bCube1;

    assert( !Cloud_IsConstant(bCube) );
    while ( 1 )
    {
        // get the node structure
        if ( Cloud_IsConstant(bCube) )
            break;

        // cofactor the cube
        if ( Cloud_IsComplement(bCube) )
        {
            bCube0 = Cloud_Not( cloudE(bCube) );
            bCube1 = Cloud_Not( cloudT(bCube) );
        }
        else
        {
            bCube0 = cloudE(bCube);
            bCube1 = cloudT(bCube);
        }

        if ( bCube0 != dd->zero )
        {
            assert( bCube1 == dd->zero );
            printf( "[%d]'", cloudV(bCube) );
            bCube = bCube0;
        }
        else
        {
            assert( bCube1 != dd->zero );
            printf( "[%d]", cloudV(bCube) );
            bCube = bCube1;
        }
    }
}


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

  Synopsis    [Prints info.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
void Cloud_PrintInfo( CloudManager * dd )
{
    if ( dd == NULL ) return;
    printf( "The number of unique table nodes allocated = %12d.\n", dd->nNodesAlloc );
    printf( "The number of unique table nodes present   = %12d.\n", dd->nNodesCur );
    printf( "The number of unique table hits            = %12d.\n", dd->nUniqueHits );
    printf( "The number of unique table misses          = %12d.\n", dd->nUniqueMisses );
    printf( "The number of unique table steps           = %12d.\n", dd->nUniqueSteps );
    printf( "The number of cache hits                   = %12d.\n", dd->nCacheHits );
    printf( "The number of cache misses                 = %12d.\n", dd->nCacheMisses );
    printf( "The current signature                      = %12d.\n", dd->nSignCur );
    printf( "The total memory in use                    = %12d.\n", dd->nMemUsed );
}

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

  Synopsis    [Prints the state of the hash table.]

  Description []

  SideEffects []

  SeeAlso     []

******************************************************************************/
void Cloud_PrintHashTable( CloudManager * dd )
{
    int i;

    for ( i = 0; i < dd->nNodesAlloc; i++ )
        if ( dd->tUnique[i].v == CLOUD_CONST_INDEX )
            printf( "-" );
        else
            printf( "+" );
    printf( "\n" );
}


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