/**Function********************************************************************
Synopsis [Computes the negative cofactor of a ZDD w.r.t. a variable.]
Description [Computes the negative cofactor of a ZDD w.r.t. a
variable. In terms of combinations, the result is the set of all
combinations in which the variable is negated. Returns a pointer to
the result if successful; NULL otherwise. cuddZddSubset0 performs
the same function as Cudd_zddSubset0, but does not restart if
reordering has taken place. Therefore it can be called from within a
recursive procedure.]
SideEffects [None]
SeeAlso [cuddZddSubset1 Cudd_zddSubset0]
******************************************************************************/
DdNode *
cuddZddSubset0(
DdManager * dd,
DdNode * P,
int var)
{
DdNode *zvar, *r;
DdNode *base, *empty;
base = DD_ONE(dd);
empty = DD_ZERO(dd);
zvar = cuddUniqueInterZdd(dd, var, base, empty);
if (zvar == NULL) {
return(NULL);
} else {
cuddRef(zvar);
r = zdd_subset0_aux(dd, P, zvar);
if (r == NULL) {
Cudd_RecursiveDerefZdd(dd, zvar);
return(NULL);
}
cuddRef(r);
Cudd_RecursiveDerefZdd(dd, zvar);
}
cuddDeref(r);
return(r);
} /* end of cuddZddSubset0 */
/**Function********************************************************************
Synopsis [Initializes the ZDD universe.]
Description [Initializes the ZDD universe. Returns 1 if successful; 0
otherwise.]
SideEffects [None]
SeeAlso [cuddZddFreeUniv]
******************************************************************************/
int
cuddZddInitUniv(
DdManager * zdd)
{
DdNode *p, *res;
int i;
#ifdef __osf__
#pragma pointer_size save
#pragma pointer_size short
#endif
zdd->univ = ALLOC(DdNode *, zdd->sizeZ);
#ifdef __osf__
#pragma pointer_size restore
#endif
if (zdd->univ == NULL) {
zdd->errorCode = CUDD_MEMORY_OUT;
return(0);
}
res = DD_ONE(zdd);
cuddRef(res);
for (i = zdd->sizeZ - 1; i >= 0; i--) {
unsigned int index = zdd->invpermZ[i];
p = res;
res = cuddUniqueInterZdd(zdd, index, p, p);
if (res == NULL) {
Cudd_RecursiveDerefZdd(zdd,p);
FREE(zdd->univ);
return(0);
}
cuddRef(res);
cuddDeref(p);
zdd->univ[i] = res;
}
#ifdef DD_VERBOSE
cuddZddP(zdd, zdd->univ[0]);
#endif
return(1);
} /* end of cuddZddInitUniv */
/**Function********************************************************************
Synopsis [Substitutes a variable with its complement in a ZDD.]
Description [Substitutes a variable with its complement in a ZDD.
returns a pointer to the result if successful; NULL
otherwise. cuddZddChange performs the same function as
Cudd_zddChange, but does not restart if reordering has taken
place. Therefore it can be called from within a recursive
procedure.]
SideEffects [None]
SeeAlso [Cudd_zddChange]
******************************************************************************/
DdNode *
cuddZddChange(
DdManager * dd,
DdNode * P,
int var)
{
DdNode *zvar, *res;
zvar = cuddUniqueInterZdd(dd, var, DD_ONE(dd), DD_ZERO(dd));
if (zvar == NULL) return(NULL);
cuddRef(zvar);
res = cuddZddChangeAux(dd, P, zvar);
if (res == NULL) {
Cudd_RecursiveDerefZdd(dd,zvar);
return(NULL);
}
cuddRef(res);
Cudd_RecursiveDerefZdd(dd,zvar);
cuddDeref(res);
return(res);
} /* end of cuddZddChange */
