src/bdd/cudd/cuddLiteral.c File Reference

#include "util_hack.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 1.1.1.1 2003/02/24 22:23:52 wjiang 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 87 of file cuddLiteral.c.

{
    DdNode *res;

    do {
        dd->reordered = 0;
        res = cuddBddLiteralSetIntersectionRecur(dd,f,g);
    } while (dd->reordered == 1);
    return(res);

} /* 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 122 of file cuddLiteral.c.

{
    DdNode *res, *tmp;
    DdNode *F, *G;
    DdNode *fc, *gc;
    DdNode *one;
    DdNode *zero;
    unsigned int topf, topg, comple;
    int phasef, phaseg;

    statLine(dd);
    if (f == g) return(f);

    F = Cudd_Regular(f);
    G = Cudd_Regular(g);
    one = DD_ONE(dd);

    /* Here f != g. If F == G, then f and g are complementary.
    ** Since they are two cubes, this case only occurs when f == v,
    ** g == v', and v is a variable or its complement.
    */
    if (F == G) return(one);

    zero = Cudd_Not(one);
    topf = cuddI(dd,F->index);
    topg = cuddI(dd,G->index);
    /* Look for a variable common to both cubes. If there are none, this
    ** loop will stop when the constant node is reached in both cubes.
    */
    while (topf != topg) {
        if (topf < topg) {      /* move down on f */
            comple = f != F;
            f = cuddT(F);
            if (comple) f = Cudd_Not(f);
            if (f == zero) {
                f = cuddE(F);
                if (comple) f = Cudd_Not(f);
            }
            F = Cudd_Regular(f);
            topf = cuddI(dd,F->index);
        } else if (topg < topf) {
            comple = g != G;
            g = cuddT(G);
            if (comple) g = Cudd_Not(g);
            if (g == zero) {
                g = cuddE(G);
                if (comple) g = Cudd_Not(g);
            }
            G = Cudd_Regular(g);
            topg = cuddI(dd,G->index);
        }
    }

    /* At this point, f == one <=> g == 1. It suffices to test one of them. */
    if (f == one) return(one);

    res = cuddCacheLookup2(dd,Cudd_bddLiteralSetIntersection,f,g);
    if (res != NULL) {
        return(res);
    }

    /* Here f and g are both non constant and have the same top variable. */
    comple = f != F;
    fc = cuddT(F);
    phasef = 1;
    if (comple) fc = Cudd_Not(fc);
    if (fc == zero) {
        fc = cuddE(F);
        phasef = 0;
        if (comple) fc = Cudd_Not(fc);
    }
    comple = g != G;
    gc = cuddT(G);
    phaseg = 1;
    if (comple) gc = Cudd_Not(gc);
    if (gc == zero) {
        gc = cuddE(G);
        phaseg = 0;
        if (comple) gc = Cudd_Not(gc);
    }

    tmp = cuddBddLiteralSetIntersectionRecur(dd,fc,gc);
    if (tmp == NULL) {
        return(NULL);
    }

    if (phasef != phaseg) {
        res = tmp;
    } else {
        cuddRef(tmp);
        if (phasef == 0) {
            res = cuddBddAndRecur(dd,Cudd_Not(dd->vars[F->index]),tmp);
        } else {
            res = cuddBddAndRecur(dd,dd->vars[F->index],tmp);
        }
        if (res == NULL) {
            Cudd_RecursiveDeref(dd,tmp);
            return(NULL);
        }
        cuddDeref(tmp); /* Just cuddDeref, because it is included in result */
    }

    cuddCacheInsert2(dd,Cudd_bddLiteralSetIntersection,f,g,res);

    return(res);

} /* end of cuddBddLiteralSetIntersectionRecur */

---

Variable Documentation

char rcsid [] DD_UNUSED = "$Id: cuddLiteral.c,v 1.1.1.1 2003/02/24 22:23:52 wjiang 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:

• Cudd_bddLiteralSetIntersection()

Internal procedures included in this file:

• cuddBddLiteralSetIntersectionRecur()

]

Author [Fabio Somenzi]

Copyright [This file was created at the University of Colorado at Boulder. The University of Colorado at Boulder makes no warranty about the suitability of this software for any purpose. It is presented on an AS IS basis.]

Definition at line 49 of file cuddLiteral.c.