/**Function********************************************************************
Synopsis [Checks whether g is the BDD of a cube.]
Description [Checks whether g is the BDD of a cube. Returns 1 in case
of success; 0 otherwise. The constant 1 is a valid cube, but all other
constant functions cause cuddCheckCube to return 0.]
SideEffects [None]
SeeAlso []
******************************************************************************/
int
cuddCheckCube(
DdManager * dd,
DdNode * g)
{
DdNode *g1,*g0,*one,*zero;
one = DD_ONE(dd);
if (g == one) return(1);
if (Cudd_IsConstant(g)) return(0);
zero = Cudd_Not(one);
cuddGetBranches(g,&g1,&g0);
if (g0 == zero) {
return(cuddCheckCube(dd, g1));
}
if (g1 == zero) {
return(cuddCheckCube(dd, g0));
}
return(0);
} /* end of cuddCheckCube */
/**Function********************************************************************
Synopsis [Computes the compatible projection of R w.r.t. cube Y.]
Description [Computes the compatible projection of relation R with
respect to cube Y. Returns a pointer to the c-projection if
successful; NULL otherwise. For a comparison between Cudd_CProjection
and Cudd_PrioritySelect, see the documentation of the latter.]
SideEffects [None]
SeeAlso [Cudd_PrioritySelect]
******************************************************************************/
DdNode *
Cudd_CProjection(
DdManager * dd,
DdNode * R,
DdNode * Y)
{
DdNode *res;
DdNode *support;
if (cuddCheckCube(dd,Y) == 0) {
(void) fprintf(dd->err,
"Error: The third argument of Cudd_CProjection should be a cube\n");
dd->errorCode = CUDD_INVALID_ARG;
return(NULL);
}
/* Compute the support of Y, which is used by the abstraction step
** in cuddCProjectionRecur.
*/
support = Cudd_Support(dd,Y);
if (support == NULL) return(NULL);
cuddRef(support);
do {
dd->reordered = 0;
res = cuddCProjectionRecur(dd,R,Y,support);
} while (dd->reordered == 1);
if (res == NULL) {
Cudd_RecursiveDeref(dd,support);
return(NULL);
}
cuddRef(res);
Cudd_RecursiveDeref(dd,support);
cuddDeref(res);
return(res);
} /* end of Cudd_CProjection */