cuddAndAbs.c File Reference

#include "misc/util/util_hack.h"
#include "cuddInt.h"

Go to the source code of this file.

Functions
DdNode *	Cudd_bddAndAbstract (DdManager *manager, DdNode *f, DdNode *g, DdNode *cube)
DdNode *	Cudd_bddAndAbstractLimit (DdManager *manager, DdNode *f, DdNode *g, DdNode *cube, unsigned int limit)
DdNode *	cuddBddAndAbstractRecur (DdManager *manager, DdNode *f, DdNode *g, DdNode *cube)

Variables
static ABC_NAMESPACE_IMPL_START char rcsid[]	DD_UNUSED = "$Id: cuddAndAbs.c,v 1.19 2004/08/13 18:04:46 fabio Exp $"

Function Documentation

DdNode* Cudd_bddAndAbstract	(	DdManager *	manager,
		DdNode *	f,
		DdNode *	g,
		DdNode *	cube
	)

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

Synopsis [Takes the AND of two BDDs and simultaneously abstracts the variables in cube.]

Description [Takes the AND of two BDDs and simultaneously abstracts the variables in cube. The variables are existentially abstracted. Returns a pointer to the result is successful; NULL otherwise. Cudd_bddAndAbstract implements the semiring matrix multiplication algorithm for the boolean semiring.]

SideEffects [None]

SeeAlso [Cudd_addMatrixMultiply Cudd_addTriangle Cudd_bddAnd]

Definition at line 124 of file cuddAndAbs.c.

{
    DdNode *res;

    do {
        manager->reordered = 0;
        res = cuddBddAndAbstractRecur(manager, f, g, cube);
    } while (manager->reordered == 1);
    return(res);

} /* end of Cudd_bddAndAbstract */

DdNode* Cudd_bddAndAbstractLimit	(	DdManager *	manager,
		DdNode *	f,
		DdNode *	g,
		DdNode *	cube,
		unsigned int	limit
	)

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

Synopsis [Takes the AND of two BDDs and simultaneously abstracts the variables in cube. Returns NULL if too many nodes are required.]

Description [Takes the AND of two BDDs and simultaneously abstracts the variables in cube. The variables are existentially abstracted. Returns a pointer to the result is successful; NULL otherwise. In particular, if the number of new nodes created exceeds limit, this function returns NULL.]

SideEffects [None]

SeeAlso [Cudd_bddAndAbstract]

Definition at line 158 of file cuddAndAbs.c.

{
    DdNode *res;
    unsigned int saveLimit = manager->maxLive;

    manager->maxLive = (manager->keys - manager->dead) +
      (manager->keysZ - manager->deadZ) + limit;
    do {
        manager->reordered = 0;
        res = cuddBddAndAbstractRecur(manager, f, g, cube);
    } while (manager->reordered == 1);
    manager->maxLive = saveLimit;
    return(res);

} /* end of Cudd_bddAndAbstractLimit */

DdNode* cuddBddAndAbstractRecur	(	DdManager *	manager,
		DdNode *	f,
		DdNode *	g,
		DdNode *	cube
	)

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

Synopsis [Takes the AND of two BDDs and simultaneously abstracts the variables in cube.]

Description [Takes the AND of two BDDs and simultaneously abstracts the variables in cube. The variables are existentially abstracted. Returns a pointer to the result is successful; NULL otherwise.]

SideEffects [None]

SeeAlso [Cudd_bddAndAbstract]

Definition at line 200 of file cuddAndAbs.c.

{
    DdNode *F, *ft, *fe, *G, *gt, *ge;
    DdNode *one, *zero, *r, *t, *e;
    unsigned int topf, topg, topcube, top, index;

    statLine(manager);
    one = DD_ONE(manager);
    zero = Cudd_Not(one);

    /* Terminal cases. */
    if (f == zero || g == zero || f == Cudd_Not(g)) return(zero);
    if (f == one && g == one)   return(one);

    if (cube == one) {
        return(cuddBddAndRecur(manager, f, g));
    }
    if (f == one || f == g) {
        return(cuddBddExistAbstractRecur(manager, g, cube));
    }
    if (g == one) {
        return(cuddBddExistAbstractRecur(manager, f, cube));
    }
    /* At this point f, g, and cube are not constant. */

    if (f > g) { /* Try to increase cache efficiency. */
        DdNode *tmp = f;
        f = g;
        g = tmp;
    }

    /* Here we can skip the use of cuddI, because the operands are known
    ** to be non-constant.
    */
    F = Cudd_Regular(f);
    G = Cudd_Regular(g);
    topf = manager->perm[F->index];
    topg = manager->perm[G->index];
    top = ddMin(topf, topg);
    topcube = manager->perm[cube->index];

    while (topcube < top) {
        cube = cuddT(cube);
        if (cube == one) {
            return(cuddBddAndRecur(manager, f, g));
        }
        topcube = manager->perm[cube->index];
    }
    /* Now, topcube >= top. */

    /* Check cache. */
    if (F->ref != 1 || G->ref != 1) {
        r = cuddCacheLookup(manager, DD_BDD_AND_ABSTRACT_TAG, f, g, cube);
        if (r != NULL) {
            return(r);
        }
    }

    if ( manager->TimeStop && Abc_Clock() > manager->TimeStop )
        return NULL;

    if (topf == top) {
        index = F->index;
        ft = cuddT(F);
        fe = cuddE(F);
        if (Cudd_IsComplement(f)) {
            ft = Cudd_Not(ft);
            fe = Cudd_Not(fe);
        }
    } else {
        index = G->index;
        ft = fe = f;
    }

    if (topg == top) {
        gt = cuddT(G);
        ge = cuddE(G);
        if (Cudd_IsComplement(g)) {
            gt = Cudd_Not(gt);
            ge = Cudd_Not(ge);
        }
    } else {
        gt = ge = g;
    }

    if (topcube == top) {       /* quantify */
        DdNode *Cube = cuddT(cube);
        t = cuddBddAndAbstractRecur(manager, ft, gt, Cube);
        if (t == NULL) return(NULL);
        /* Special case: 1 OR anything = 1. Hence, no need to compute
        ** the else branch if t is 1. Likewise t + t * anything == t.
        ** Notice that t == fe implies that fe does not depend on the
        ** variables in Cube. Likewise for t == ge.
        */
        if (t == one || t == fe || t == ge) {
            if (F->ref != 1 || G->ref != 1)
                cuddCacheInsert(manager, DD_BDD_AND_ABSTRACT_TAG,
                                f, g, cube, t);
            return(t);
        }
        cuddRef(t);
        /* Special case: t + !t * anything == t + anything. */
        if (t == Cudd_Not(fe)) {
            e = cuddBddExistAbstractRecur(manager, ge, Cube);
        } else if (t == Cudd_Not(ge)) {
            e = cuddBddExistAbstractRecur(manager, fe, Cube);
        } else {
            e = cuddBddAndAbstractRecur(manager, fe, ge, Cube);
        }
        if (e == NULL) {
            Cudd_IterDerefBdd(manager, t);
            return(NULL);
        }
        if (t == e) {
            r = t;
            cuddDeref(t);
        } else {
            cuddRef(e);
            r = cuddBddAndRecur(manager, Cudd_Not(t), Cudd_Not(e));
            if (r == NULL) {
                Cudd_IterDerefBdd(manager, t);
                Cudd_IterDerefBdd(manager, e);
                return(NULL);
            }
            r = Cudd_Not(r);
            cuddRef(r);
            Cudd_DelayedDerefBdd(manager, t);
            Cudd_DelayedDerefBdd(manager, e);
            cuddDeref(r);
        }
    } else {
        t = cuddBddAndAbstractRecur(manager, ft, gt, cube);
        if (t == NULL) return(NULL);
        cuddRef(t);
        e = cuddBddAndAbstractRecur(manager, fe, ge, cube);
        if (e == NULL) {
            Cudd_IterDerefBdd(manager, t);
            return(NULL);
        }
        if (t == e) {
            r = t;
            cuddDeref(t);
        } else {
            cuddRef(e);
            if (Cudd_IsComplement(t)) {
                r = cuddUniqueInter(manager, (int) index,
                                    Cudd_Not(t), Cudd_Not(e));
                if (r == NULL) {
                    Cudd_IterDerefBdd(manager, t);
                    Cudd_IterDerefBdd(manager, e);
                    return(NULL);
                }
                r = Cudd_Not(r);
            } else {
                r = cuddUniqueInter(manager,(int)index,t,e);
                if (r == NULL) {
                    Cudd_IterDerefBdd(manager, t);
                    Cudd_IterDerefBdd(manager, e);
                    return(NULL);
                }
            }
            cuddDeref(e);
            cuddDeref(t);
        }
    }

    if (F->ref != 1 || G->ref != 1)
        cuddCacheInsert(manager, DD_BDD_AND_ABSTRACT_TAG, f, g, cube, r);
    return (r);

} /* end of cuddBddAndAbstractRecur */

Variable Documentation

ABC_NAMESPACE_IMPL_START char rcsid [] DD_UNUSED = "$Id: cuddAndAbs.c,v 1.19 2004/08/13 18:04:46 fabio Exp $"

static

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

FileName [cuddAndAbs.c]

PackageName [cudd]

Synopsis [Combined AND and existential abstraction for BDDs]

Description [External procedures included in this module:

• Cudd_bddAndAbstract()
• Cudd_bddAndAbstractLimit()

Internal procedures included in this module:

• cuddBddAndAbstractRecur()

]

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 83 of file cuddAndAbs.c.