src/cuBdd/cuddLiteral.c File Reference

#include "util.h"
#include "cuddInt.h"
Include dependency graph for cuddLiteral.c:

Go to the source code of this file.

Functions

DdNode * Cudd_bddLiteralSetIntersection (DdManager *dd, DdNode *f, DdNode *g)
DdNode * cuddBddLiteralSetIntersectionRecur (DdManager *dd, DdNode *f, DdNode *g)

Variables

static char rcsid[] DD_UNUSED = "$Id: cuddLiteral.c,v 1.8 2004/08/13 18:04:50 fabio Exp $"

Function Documentation

DdNode* Cudd_bddLiteralSetIntersection ( DdManager *  dd,
DdNode *  f,
DdNode *  g 
)

AutomaticStart AutomaticEnd Function********************************************************************

Synopsis [Computes the intesection of two sets of literals represented as BDDs.]

Description [Computes the intesection of two sets of literals represented as BDDs. Each set is represented as a cube of the literals in the set. The empty set is represented by the constant 1. No variable can be simultaneously present in both phases in a set. Returns a pointer to the BDD representing the intersected sets, if successful; NULL otherwise.]

SideEffects [None]

Definition at line 114 of file cuddLiteral.c.

00118 {
00119     DdNode *res;
00120 
00121     do {
00122         dd->reordered = 0;
00123         res = cuddBddLiteralSetIntersectionRecur(dd,f,g);
00124     } while (dd->reordered == 1);
00125     return(res);
00126 
00127 } /* end of Cudd_bddLiteralSetIntersection */

DdNode* cuddBddLiteralSetIntersectionRecur ( DdManager *  dd,
DdNode *  f,
DdNode *  g 
)

Function********************************************************************

Synopsis [Performs the recursive step of Cudd_bddLiteralSetIntersection.]

Description [Performs the recursive step of Cudd_bddLiteralSetIntersection. Scans the cubes for common variables, and checks whether they agree in phase. Returns a pointer to the resulting cube if successful; NULL otherwise.]

SideEffects [None]

Definition at line 149 of file cuddLiteral.c.

00153 {
00154     DdNode *res, *tmp;
00155     DdNode *F, *G;
00156     DdNode *fc, *gc;
00157     DdNode *one;
00158     DdNode *zero;
00159     unsigned int topf, topg, comple;
00160     int phasef, phaseg;
00161 
00162     statLine(dd);
00163     if (f == g) return(f);
00164 
00165     F = Cudd_Regular(f);
00166     G = Cudd_Regular(g);
00167     one = DD_ONE(dd);
00168 
00169     /* Here f != g. If F == G, then f and g are complementary.
00170     ** Since they are two cubes, this case only occurs when f == v,
00171     ** g == v', and v is a variable or its complement.
00172     */
00173     if (F == G) return(one);
00174 
00175     zero = Cudd_Not(one);
00176     topf = cuddI(dd,F->index);
00177     topg = cuddI(dd,G->index);
00178     /* Look for a variable common to both cubes. If there are none, this
00179     ** loop will stop when the constant node is reached in both cubes.
00180     */
00181     while (topf != topg) {
00182         if (topf < topg) {      /* move down on f */
00183             comple = f != F;
00184             f = cuddT(F);
00185             if (comple) f = Cudd_Not(f);
00186             if (f == zero) {
00187                 f = cuddE(F);
00188                 if (comple) f = Cudd_Not(f);
00189             }
00190             F = Cudd_Regular(f);
00191             topf = cuddI(dd,F->index);
00192         } else if (topg < topf) {
00193             comple = g != G;
00194             g = cuddT(G);
00195             if (comple) g = Cudd_Not(g);
00196             if (g == zero) {
00197                 g = cuddE(G);
00198                 if (comple) g = Cudd_Not(g);
00199             }
00200             G = Cudd_Regular(g);
00201             topg = cuddI(dd,G->index);
00202         }
00203     }
00204 
00205     /* At this point, f == one <=> g == 1. It suffices to test one of them. */
00206     if (f == one) return(one);
00207 
00208     res = cuddCacheLookup2(dd,Cudd_bddLiteralSetIntersection,f,g);
00209     if (res != NULL) {
00210         return(res);
00211     }
00212 
00213     /* Here f and g are both non constant and have the same top variable. */
00214     comple = f != F;
00215     fc = cuddT(F);
00216     phasef = 1;
00217     if (comple) fc = Cudd_Not(fc);
00218     if (fc == zero) {
00219         fc = cuddE(F);
00220         phasef = 0;
00221         if (comple) fc = Cudd_Not(fc);
00222     }
00223     comple = g != G;
00224     gc = cuddT(G);
00225     phaseg = 1;
00226     if (comple) gc = Cudd_Not(gc);
00227     if (gc == zero) {
00228         gc = cuddE(G);
00229         phaseg = 0;
00230         if (comple) gc = Cudd_Not(gc);
00231     }
00232 
00233     tmp = cuddBddLiteralSetIntersectionRecur(dd,fc,gc);
00234     if (tmp == NULL) {
00235         return(NULL);
00236     }
00237 
00238     if (phasef != phaseg) {
00239         res = tmp;
00240     } else {
00241         cuddRef(tmp);
00242         if (phasef == 0) {
00243             res = cuddBddAndRecur(dd,Cudd_Not(dd->vars[F->index]),tmp);
00244         } else {
00245             res = cuddBddAndRecur(dd,dd->vars[F->index],tmp);
00246         }
00247         if (res == NULL) {
00248             Cudd_RecursiveDeref(dd,tmp);
00249             return(NULL);
00250         }
00251         cuddDeref(tmp); /* Just cuddDeref, because it is included in result */
00252     }
00253 
00254     cuddCacheInsert2(dd,Cudd_bddLiteralSetIntersection,f,g,res);
00255 
00256     return(res);
00257 
00258 } /* end of cuddBddLiteralSetIntersectionRecur */

Variable Documentation

char rcsid [] DD_UNUSED = "$Id: cuddLiteral.c,v 1.8 2004/08/13 18:04:50 fabio Exp $" [static]

CFile***********************************************************************

FileName [cuddLiteral.c]

PackageName [cudd]

Synopsis [Functions for manipulation of literal sets represented by BDDs.]

Description [External procedures included in this file:

Internal procedures included in this file:

]

Author [Fabio Somenzi]

Copyright [Copyright (c) 1995-2004, Regents of the University of Colorado

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

Neither the name of the University of Colorado nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.]

Definition at line 76 of file cuddLiteral.c.

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