/**Function********************************************************************
Synopsis [Existentially abstracts all the variables in cube from f.]
Description [Existentially abstracts all the variables in cube from f.
Returns the abstracted BDD if successful; NULL if the intermediate
result blows up or more new nodes than <code>limit</code> are
required.]
SideEffects [None]
SeeAlso [Cudd_bddExistAbstract]
******************************************************************************/
DdNode *
Cudd_bddExistAbstractLimit(
DdManager * manager,
DdNode * f,
DdNode * cube,
unsigned int limit)
{
DdNode *res;
unsigned int saveLimit = manager->maxLive;
if (bddCheckPositiveCube(manager, cube) == 0) {
(void) fprintf(manager->err,
"Error: Can only abstract positive cubes\n");
manager->errorCode = CUDD_INVALID_ARG;
return(NULL);
}
manager->maxLive = (manager->keys - manager->dead) +
(manager->keysZ - manager->deadZ) + limit;
do {
manager->reordered = 0;
res = cuddBddExistAbstractRecur(manager, f, cube);
} while (manager->reordered == 1);
manager->maxLive = saveLimit;
return(res);
} /* end of Cudd_bddExistAbstractLimit */
/**
@brief Existentially abstracts all the variables in cube from f.
@return the abstracted %BDD if successful; NULL otherwise.
@sideeffect None
@see Cudd_bddUnivAbstract Cudd_addExistAbstract
*/
DdNode *
Cudd_bddExistAbstract(
DdManager * manager,
DdNode * f,
DdNode * cube)
{
DdNode *res;
if (bddCheckPositiveCube(manager, cube) == 0) {
(void) fprintf(manager->err,
"Error: Can only abstract positive cubes\n");
manager->errorCode = CUDD_INVALID_ARG;
return(NULL);
}
do {
manager->reordered = 0;
res = cuddBddExistAbstractRecur(manager, f, cube);
} while (manager->reordered == 1);
if (manager->errorCode == CUDD_TIMEOUT_EXPIRED && manager->timeoutHandler) {
manager->timeoutHandler(manager, manager->tohArg);
}
return(res);
} /* end of Cudd_bddExistAbstract */
/**Function********************************************************************
Synopsis [Universally abstracts all the variables in cube from f.]
Description [Universally abstracts all the variables in cube from f.
Returns the abstracted BDD if successful; NULL otherwise.]
SideEffects [None]
SeeAlso [Cudd_bddExistAbstract Cudd_addUnivAbstract]
******************************************************************************/
DdNode *
Cudd_bddUnivAbstract(
DdManager * manager,
DdNode * f,
DdNode * cube)
{
DdNode *res;
if (bddCheckPositiveCube(manager, cube) == 0) {
(void) fprintf(manager->err,
"Error: Can only abstract positive cubes\n");
manager->errorCode = CUDD_INVALID_ARG;
return(NULL);
}
do {
manager->reordered = 0;
res = cuddBddExistAbstractRecur(manager, Cudd_Not(f), cube);
} while (manager->reordered == 1);
if (res != NULL) res = Cudd_Not(res);
return(res);
} /* end of Cudd_bddUnivAbstract */
/**Function********************************************************************
Synopsis [Performs a recursive step of Extra_zddGetSymmetricVars.]
Description [Returns the set of ZDD singletons, containing those positive
ZDD variables that correspond to BDD variables x, for which it is true
that bF(x=0) == bG(x=1).]
SideEffects []
SeeAlso []
******************************************************************************/
DdNode * extraZddGetSymmetricVars(
DdManager * dd, /* the DD manager */
DdNode * bF, /* the first function - originally, the positive cofactor */
DdNode * bG, /* the second function - originally, the negative cofactor */
DdNode * bVars) /* the set of variables, on which F and G depend */
{
DdNode * zRes;
DdNode * bFR = Cudd_Regular(bF);
DdNode * bGR = Cudd_Regular(bG);
if ( cuddIsConstant(bFR) && cuddIsConstant(bGR) )
{
if ( bF == bG )
return extraZddGetSingletons( dd, bVars );
else
return z0;
}
assert( bVars != b1 );
if ( (zRes = cuddCacheLookupZdd(dd, DD_GET_SYMM_VARS_TAG, bF, bG, bVars)) )
return zRes;
else
{
DdNode * zRes0, * zRes1;
DdNode * zPlus, * zTemp;
DdNode * bF0, * bF1;
DdNode * bG0, * bG1;
DdNode * bVarsNew;
int LevelF = cuddI(dd,bFR->index);
int LevelG = cuddI(dd,bGR->index);
int LevelFG;
if ( LevelF < LevelG )
LevelFG = LevelF;
else
LevelFG = LevelG;
// at least one of the arguments is not a constant
assert( LevelFG < dd->size );
// every variable in bF and bG should be also in bVars, therefore LevelFG cannot be above LevelV
// if LevelFG is below LevelV, scroll through the vars in bVars to the same level as LevelFG
for ( bVarsNew = bVars; LevelFG > dd->perm[bVarsNew->index]; bVarsNew = cuddT(bVarsNew) );
assert( LevelFG == dd->perm[bVarsNew->index] );
// cofactor the functions
if ( LevelF == LevelFG )
{
if ( bFR != bF ) // bF is complemented
{
bF0 = Cudd_Not( cuddE(bFR) );
bF1 = Cudd_Not( cuddT(bFR) );
}
else
{
bF0 = cuddE(bFR);
bF1 = cuddT(bFR);
}
}
else
bF0 = bF1 = bF;
if ( LevelG == LevelFG )
{
if ( bGR != bG ) // bG is complemented
{
bG0 = Cudd_Not( cuddE(bGR) );
bG1 = Cudd_Not( cuddT(bGR) );
}
else
{
bG0 = cuddE(bGR);
bG1 = cuddT(bGR);
}
}
else
bG0 = bG1 = bG;
// solve subproblems
zRes0 = extraZddGetSymmetricVars( dd, bF0, bG0, cuddT(bVarsNew) );
if ( zRes0 == NULL )
return NULL;
cuddRef( zRes0 );
// if there is not symmetries in the negative cofactor
// there is no need to test the positive cofactor
if ( zRes0 == z0 )
zRes = zRes0; // zRes takes reference
else
{
zRes1 = extraZddGetSymmetricVars( dd, bF1, bG1, cuddT(bVarsNew) );
if ( zRes1 == NULL )
{
Cudd_RecursiveDerefZdd( dd, zRes0 );
return NULL;
}
cuddRef( zRes1 );
// only those variables should belong to the resulting set
// for which the property is true for both cofactors
zRes = cuddZddIntersect( dd, zRes0, zRes1 );
if ( zRes == NULL )
{
Cudd_RecursiveDerefZdd( dd, zRes0 );
Cudd_RecursiveDerefZdd( dd, zRes1 );
return NULL;
}
cuddRef( zRes );
Cudd_RecursiveDerefZdd( dd, zRes0 );
Cudd_RecursiveDerefZdd( dd, zRes1 );
}
// add one more singleton if the property is true for this variable
if ( bF0 == bG1 )
{
zPlus = cuddZddGetNode( dd, 2*bVarsNew->index, z1, z0 );
if ( zPlus == NULL )
{
Cudd_RecursiveDerefZdd( dd, zRes );
return NULL;
}
cuddRef( zPlus );
// add these variable pairs to the result
zRes = cuddZddUnion( dd, zTemp = zRes, zPlus );
if ( zRes == NULL )
{
Cudd_RecursiveDerefZdd( dd, zTemp );
Cudd_RecursiveDerefZdd( dd, zPlus );
return NULL;
}
cuddRef( zRes );
Cudd_RecursiveDerefZdd( dd, zTemp );
Cudd_RecursiveDerefZdd( dd, zPlus );
}
if ( bF == bG && bVars != bVarsNew )
{
// if the functions are equal, so are their cofactors
// add those variables from V that are above F and G
DdNode * bVarsExtra;
assert( LevelFG > dd->perm[bVars->index] );
// create the BDD of the extra variables
bVarsExtra = cuddBddExistAbstractRecur( dd, bVars, bVarsNew );
if ( bVarsExtra == NULL )
{
Cudd_RecursiveDerefZdd( dd, zRes );
return NULL;
}
cuddRef( bVarsExtra );
zPlus = extraZddGetSingletons( dd, bVarsExtra );
if ( zPlus == NULL )
{
Cudd_RecursiveDeref( dd, bVarsExtra );
Cudd_RecursiveDerefZdd( dd, zRes );
return NULL;
}
cuddRef( zPlus );
Cudd_RecursiveDeref( dd, bVarsExtra );
// add these to the result
zRes = cuddZddUnion( dd, zTemp = zRes, zPlus );
if ( zRes == NULL )
{
Cudd_RecursiveDerefZdd( dd, zTemp );
Cudd_RecursiveDerefZdd( dd, zPlus );
return NULL;
}
cuddRef( zRes );
Cudd_RecursiveDerefZdd( dd, zTemp );
Cudd_RecursiveDerefZdd( dd, zPlus );
}
cuddDeref( zRes );
cuddCacheInsert( dd, DD_GET_SYMM_VARS_TAG, bF, bG, bVars, zRes );
return zRes;
}
} /* end of extraZddGetSymmetricVars */
/**Function********************************************************************
Synopsis [Performs a recursive step of Extra_bddReduceVarSet.]
Description [Returns the set of all variables in the given set that are not in the
support of the given function.]
SideEffects []
SeeAlso []
******************************************************************************/
DdNode * extraBddReduceVarSet(
DdManager * dd, /* the DD manager */
DdNode * bVars, /* the set of variables to be reduced */
DdNode * bF) /* the function whose support is used for reduction */
{
DdNode * bRes;
DdNode * bFR = Cudd_Regular(bF);
if ( cuddIsConstant(bFR) || bVars == b1 )
return bVars;
if ( (bRes = cuddCacheLookup2(dd, extraBddReduceVarSet, bVars, bF)) )
return bRes;
else
{
DdNode * bF0, * bF1;
DdNode * bVarsThis, * bVarsLower, * bTemp;
int LevelF;
// if LevelF is below LevelV, scroll through the vars in bVars
LevelF = dd->perm[bFR->index];
for ( bVarsThis = bVars; LevelF > cuddI(dd,bVarsThis->index); bVarsThis = cuddT(bVarsThis) );
// scroll also through the current var, because it should be not be added
if ( LevelF == cuddI(dd,bVarsThis->index) )
bVarsLower = cuddT(bVarsThis);
else
bVarsLower = bVarsThis;
// cofactor the function
if ( bFR != bF ) // bFunc is complemented
{
bF0 = Cudd_Not( cuddE(bFR) );
bF1 = Cudd_Not( cuddT(bFR) );
}
else
{
bF0 = cuddE(bFR);
bF1 = cuddT(bFR);
}
// solve subproblems
bRes = extraBddReduceVarSet( dd, bVarsLower, bF0 );
if ( bRes == NULL )
return NULL;
cuddRef( bRes );
bRes = extraBddReduceVarSet( dd, bTemp = bRes, bF1 );
if ( bRes == NULL )
{
Cudd_RecursiveDeref( dd, bTemp );
return NULL;
}
cuddRef( bRes );
Cudd_RecursiveDeref( dd, bTemp );
// the current var should not be added
// add the skipped vars
if ( bVarsThis != bVars )
{
DdNode * bVarsExtra;
// extract the skipped variables
bVarsExtra = cuddBddExistAbstractRecur( dd, bVars, bVarsThis );
if ( bVarsExtra == NULL )
{
Cudd_RecursiveDeref( dd, bRes );
return NULL;
}
cuddRef( bVarsExtra );
// add these variables
bRes = cuddBddAndRecur( dd, bTemp = bRes, bVarsExtra );
if ( bRes == NULL )
{
Cudd_RecursiveDeref( dd, bTemp );
Cudd_RecursiveDeref( dd, bVarsExtra );
return NULL;
}
cuddRef( bRes );
Cudd_RecursiveDeref( dd, bTemp );
Cudd_RecursiveDeref( dd, bVarsExtra );
}
cuddDeref( bRes );
cuddCacheInsert2( dd, extraBddReduceVarSet, bVars, bF, bRes );
return bRes;
}
} /* end of extraBddReduceVarSet */
/**Function********************************************************************
Synopsis [Performs the recursive step of Cudd_CProjection.]
Description [Performs the recursive step of Cudd_CProjection. Returns
the projection if successful; NULL otherwise.]
SideEffects [None]
SeeAlso [Cudd_CProjection]
******************************************************************************/
DdNode *
cuddCProjectionRecur(
DdManager * dd,
DdNode * R,
DdNode * Y,
DdNode * Ysupp)
{
DdNode *res, *res1, *res2, *resA;
DdNode *r, *y, *RT, *RE, *YT, *YE, *Yrest, *Ra, *Ran, *Gamma, *Alpha;
unsigned int topR, topY, top, index;
DdNode *one = DD_ONE(dd);
statLine(dd);
if (Y == one) return(R);
#ifdef DD_DEBUG
assert(!Cudd_IsConstant(Y));
#endif
if (R == Cudd_Not(one)) return(R);
res = cuddCacheLookup2(dd, Cudd_CProjection, R, Y);
if (res != NULL) return(res);
r = Cudd_Regular(R);
topR = cuddI(dd,r->index);
y = Cudd_Regular(Y);
topY = cuddI(dd,y->index);
top = ddMin(topR, topY);
/* Compute the cofactors of R */
if (topR == top) {
index = r->index;
RT = cuddT(r);
RE = cuddE(r);
if (r != R) {
RT = Cudd_Not(RT); RE = Cudd_Not(RE);
}
} else {
RT = RE = R;
}
if (topY > top) {
/* Y does not depend on the current top variable.
** We just need to compute the results on the two cofactors of R
** and make them the children of a node labeled r->index.
*/
res1 = cuddCProjectionRecur(dd,RT,Y,Ysupp);
if (res1 == NULL) return(NULL);
cuddRef(res1);
res2 = cuddCProjectionRecur(dd,RE,Y,Ysupp);
if (res2 == NULL) {
Cudd_RecursiveDeref(dd,res1);
return(NULL);
}
cuddRef(res2);
res = cuddBddIteRecur(dd, dd->vars[index], res1, res2);
if (res == NULL) {
Cudd_RecursiveDeref(dd,res1);
Cudd_RecursiveDeref(dd,res2);
return(NULL);
}
/* If we have reached this point, res1 and res2 are now
** incorporated in res. cuddDeref is therefore sufficient.
*/
cuddDeref(res1);
cuddDeref(res2);
} else {
/* Compute the cofactors of Y */
index = y->index;
YT = cuddT(y);
YE = cuddE(y);
if (y != Y) {
YT = Cudd_Not(YT); YE = Cudd_Not(YE);
}
if (YT == Cudd_Not(one)) {
Alpha = Cudd_Not(dd->vars[index]);
Yrest = YE;
Ra = RE;
Ran = RT;
} else {
Alpha = dd->vars[index];
Yrest = YT;
Ra = RT;
Ran = RE;
}
Gamma = cuddBddExistAbstractRecur(dd,Ra,cuddT(Ysupp));
if (Gamma == NULL) return(NULL);
if (Gamma == one) {
res1 = cuddCProjectionRecur(dd,Ra,Yrest,cuddT(Ysupp));
if (res1 == NULL) return(NULL);
cuddRef(res1);
res = cuddBddAndRecur(dd, Alpha, res1);
if (res == NULL) {
Cudd_RecursiveDeref(dd,res1);
return(NULL);
}
cuddDeref(res1);
} else if (Gamma == Cudd_Not(one)) {
res1 = cuddCProjectionRecur(dd,Ran,Yrest,cuddT(Ysupp));
if (res1 == NULL) return(NULL);
cuddRef(res1);
res = cuddBddAndRecur(dd, Cudd_Not(Alpha), res1);
if (res == NULL) {
Cudd_RecursiveDeref(dd,res1);
return(NULL);
}
cuddDeref(res1);
} else {
cuddRef(Gamma);
resA = cuddCProjectionRecur(dd,Ran,Yrest,cuddT(Ysupp));
if (resA == NULL) {
Cudd_RecursiveDeref(dd,Gamma);
return(NULL);
}
cuddRef(resA);
res2 = cuddBddAndRecur(dd, Cudd_Not(Gamma), resA);
if (res2 == NULL) {
Cudd_RecursiveDeref(dd,Gamma);
Cudd_RecursiveDeref(dd,resA);
return(NULL);
}
cuddRef(res2);
Cudd_RecursiveDeref(dd,Gamma);
Cudd_RecursiveDeref(dd,resA);
res1 = cuddCProjectionRecur(dd,Ra,Yrest,cuddT(Ysupp));
if (res1 == NULL) {
Cudd_RecursiveDeref(dd,res2);
return(NULL);
}
cuddRef(res1);
res = cuddBddIteRecur(dd, Alpha, res1, res2);
if (res == NULL) {
Cudd_RecursiveDeref(dd,res1);
Cudd_RecursiveDeref(dd,res2);
return(NULL);
}
cuddDeref(res1);
cuddDeref(res2);
}
}
cuddCacheInsert2(dd,Cudd_CProjection,R,Y,res);
return(res);
} /* end of cuddCProjectionRecur */
/**
@brief Approximates the AND of two BDDs and simultaneously abstracts the
variables in cube.
@details The variables are existentially abstracted.
@return a pointer to the result is successful; NULL otherwise.
@sideeffect None
@see Cudd_bddClippingAndAbstract
*/
static DdNode *
cuddBddClipAndAbsRecur(
DdManager * manager,
DdNode * f,
DdNode * g,
DdNode * cube,
int distance,
int direction)
{
DdNode *F, *ft, *fe, *G, *gt, *ge;
DdNode *one, *zero, *r, *t, *e, *Cube;
int topf, topg, topcube, top;
unsigned int index;
ptruint cacheTag;
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(cuddBddClippingAndRecur(manager, f, g, distance, direction));
}
if (f == one || f == g) {
return (cuddBddExistAbstractRecur(manager, g, cube));
}
if (g == one) {
return (cuddBddExistAbstractRecur(manager, f, cube));
}
if (distance == 0) return(Cudd_NotCond(one,(direction == 0)));
/* At this point f, g, and cube are not constant. */
distance--;
/* Check cache. */
if (f > g) { /* Try to increase cache efficiency. */
DdNode *tmp = f;
f = g; g = tmp;
}
F = Cudd_Regular(f);
G = Cudd_Regular(g);
cacheTag = direction ? DD_BDD_CLIPPING_AND_ABSTRACT_UP_TAG :
DD_BDD_CLIPPING_AND_ABSTRACT_DOWN_TAG;
if (F->ref != 1 || G->ref != 1) {
r = cuddCacheLookup(manager, cacheTag,
f, g, cube);
if (r != NULL) {
return(r);
}
}
checkWhetherToGiveUp(manager);
/* Here we can skip the use of cuddI, because the operands are known
** to be non-constant.
*/
topf = manager->perm[F->index];
topg = manager->perm[G->index];
top = ddMin(topf, topg);
topcube = manager->perm[cube->index];
if (topcube < top) {
return(cuddBddClipAndAbsRecur(manager, f, g, cuddT(cube),
distance, direction));
}
/* Now, topcube >= top. */
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) {
Cube = cuddT(cube);
} else {
Cube = cube;
}
t = cuddBddClipAndAbsRecur(manager, ft, gt, Cube, distance, direction);
if (t == NULL) return(NULL);
/* Special case: 1 OR anything = 1. Hence, no need to compute
** the else branch if t is 1.
*/
if (t == one && topcube == top) {
if (F->ref != 1 || G->ref != 1)
cuddCacheInsert(manager, cacheTag, f, g, cube, one);
return(one);
}
cuddRef(t);
e = cuddBddClipAndAbsRecur(manager, fe, ge, Cube, distance, direction);
if (e == NULL) {
Cudd_RecursiveDeref(manager, t);
return(NULL);
}
cuddRef(e);
if (topcube == top) { /* abstract */
r = cuddBddClippingAndRecur(manager, Cudd_Not(t), Cudd_Not(e),
distance, (direction == 0));
if (r == NULL) {
Cudd_RecursiveDeref(manager, t);
Cudd_RecursiveDeref(manager, e);
return(NULL);
}
r = Cudd_Not(r);
cuddRef(r);
Cudd_RecursiveDeref(manager, t);
Cudd_RecursiveDeref(manager, e);
cuddDeref(r);
} else if (t == e) {
r = t;
cuddDeref(t);
cuddDeref(e);
} else {
if (Cudd_IsComplement(t)) {
r = cuddUniqueInter(manager,(int)index,Cudd_Not(t),Cudd_Not(e));
if (r == NULL) {
Cudd_RecursiveDeref(manager, t);
Cudd_RecursiveDeref(manager, e);
return(NULL);
}
r = Cudd_Not(r);
} else {
r = cuddUniqueInter(manager,(int)index,t,e);
if (r == NULL) {
Cudd_RecursiveDeref(manager, t);
Cudd_RecursiveDeref(manager, e);
return(NULL);
}
}
cuddDeref(e);
cuddDeref(t);
}
if (F->ref != 1 || G->ref != 1)
cuddCacheInsert(manager, cacheTag, f, g, cube, r);
return (r);
} /* end of cuddBddClipAndAbsRecur */
/**Function********************************************************************
Synopsis [Implements the recursive step of Cudd_SolveEqn.]
Description [Implements the recursive step of Cudd_SolveEqn.
Returns NULL if the intermediate solution blows up
or reordering occurs. The parametric solutions are
stored in the array G.]
SideEffects [none]
SeeAlso [Cudd_SolveEqn, Cudd_VerifySol]
******************************************************************************/
DdNode *
cuddSolveEqnRecur(
DdManager * bdd,
DdNode * F /* the left-hand side of the equation */,
DdNode * Y /* the cube of remaining y variables */,
DdNode ** G /* the array of solutions */,
int n /* number of unknowns */,
int * yIndex /* array holding the y variable indices */,
int i /* level of recursion */)
{
DdNode *Fn, *Fm1, *Fv, *Fvbar, *T, *w, *nextY, *one;
DdNodePtr *variables;
int j;
statLine(bdd);
variables = bdd->vars;
one = DD_ONE(bdd);
/* Base condition. */
if (Y == one) {
return F;
}
/* Cofactor of Y. */
yIndex[i] = Y->index;
nextY = Cudd_T(Y);
/* Universal abstraction of F with respect to the top variable index. */
Fm1 = cuddBddExistAbstractRecur(bdd, Cudd_Not(F), variables[yIndex[i]]);
if (Fm1) {
Fm1 = Cudd_Not(Fm1);
cuddRef(Fm1);
} else {
return(NULL);
}
Fn = cuddSolveEqnRecur(bdd, Fm1, nextY, G, n, yIndex, i+1);
if (Fn) {
cuddRef(Fn);
} else {
Cudd_RecursiveDeref(bdd, Fm1);
return(NULL);
}
Fv = cuddCofactorRecur(bdd, F, variables[yIndex[i]]);
if (Fv) {
cuddRef(Fv);
} else {
Cudd_RecursiveDeref(bdd, Fm1);
Cudd_RecursiveDeref(bdd, Fn);
return(NULL);
}
Fvbar = cuddCofactorRecur(bdd, F, Cudd_Not(variables[yIndex[i]]));
if (Fvbar) {
cuddRef(Fvbar);
} else {
Cudd_RecursiveDeref(bdd, Fm1);
Cudd_RecursiveDeref(bdd, Fn);
Cudd_RecursiveDeref(bdd, Fv);
return(NULL);
}
/* Build i-th component of the solution. */
w = cuddBddIteRecur(bdd, variables[yIndex[i]], Cudd_Not(Fv), Fvbar);
if (w) {
cuddRef(w);
} else {
Cudd_RecursiveDeref(bdd, Fm1);
Cudd_RecursiveDeref(bdd, Fn);
Cudd_RecursiveDeref(bdd, Fv);
Cudd_RecursiveDeref(bdd, Fvbar);
return(NULL);
}
T = cuddBddRestrictRecur(bdd, w, Cudd_Not(Fm1));
if(T) {
cuddRef(T);
} else {
Cudd_RecursiveDeref(bdd, Fm1);
Cudd_RecursiveDeref(bdd, Fn);
Cudd_RecursiveDeref(bdd, Fv);
Cudd_RecursiveDeref(bdd, Fvbar);
Cudd_RecursiveDeref(bdd, w);
return(NULL);
}
Cudd_RecursiveDeref(bdd,Fm1);
Cudd_RecursiveDeref(bdd,w);
Cudd_RecursiveDeref(bdd,Fv);
Cudd_RecursiveDeref(bdd,Fvbar);
/* Substitute components of solution already found into solution. */
for (j = n-1; j > i; j--) {
w = cuddBddComposeRecur(bdd,T, G[j], variables[yIndex[j]]);
if(w) {
cuddRef(w);
} else {
Cudd_RecursiveDeref(bdd, Fn);
Cudd_RecursiveDeref(bdd, T);
return(NULL);
}
Cudd_RecursiveDeref(bdd,T);
T = w;
}
G[i] = T;
Cudd_Deref(Fn);
return(Fn);
} /* end of cuddSolveEqnRecur */
/**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]
******************************************************************************/
DdNode *
cuddBddAndAbstractRecur(
DdManager * manager,
DdNode * f,
DdNode * g,
DdNode * cube)
{
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 && manager->TimeStop < clock() )
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 */
/**Function********************************************************************
Synopsis [Takes the exclusive OR of two BDDs and simultaneously abstracts the
variables in cube.]
Description [Takes the exclusive OR 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]
******************************************************************************/
DdNode *
cuddBddXorExistAbstractRecur(
DdManager * manager,
DdNode * f,
DdNode * g,
DdNode * cube)
{
DdNode *F, *fv, *fnv, *G, *gv, *gnv;
DdNode *one, *zero, *r, *t, *e, *Cube;
unsigned int topf, topg, topcube, top, index;
statLine(manager);
one = DD_ONE(manager);
zero = Cudd_Not(one);
/* Terminal cases. */
if (f == g) {
return(zero);
}
if (f == Cudd_Not(g)) {
return(one);
}
if (cube == one) {
return(cuddBddXorRecur(manager, f, g));
}
if (f == one) {
return(cuddBddExistAbstractRecur(manager, Cudd_Not(g), cube));
}
if (g == one) {
return(cuddBddExistAbstractRecur(manager, Cudd_Not(f), cube));
}
if (f == zero) {
return(cuddBddExistAbstractRecur(manager, g, cube));
}
if (g == zero) {
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;
}
/* Check cache. */
r = cuddCacheLookup(manager, DD_BDD_XOR_EXIST_ABSTRACT_TAG, f, g, cube);
if (r != NULL) {
return(r);
}
/* Here we can skip the use of cuddI, because the operands are known
** to be non-constant.
*/
F = Cudd_Regular(f);
topf = manager->perm[F->index];
G = Cudd_Regular(g);
topg = manager->perm[G->index];
top = ddMin(topf, topg);
topcube = manager->perm[cube->index];
if (topcube < top) {
return(cuddBddXorExistAbstractRecur(manager, f, g, cuddT(cube)));
}
/* Now, topcube >= top. */
if (topf == top) {
index = F->index;
fv = cuddT(F);
fnv = cuddE(F);
if (Cudd_IsComplement(f)) {
fv = Cudd_Not(fv);
fnv = Cudd_Not(fnv);
}
} else {
index = G->index;
fv = fnv = f;
}
if (topg == top) {
gv = cuddT(G);
gnv = cuddE(G);
if (Cudd_IsComplement(g)) {
gv = Cudd_Not(gv);
gnv = Cudd_Not(gnv);
}
} else {
gv = gnv = g;
}
if (topcube == top) {
Cube = cuddT(cube);
} else {
Cube = cube;
}
t = cuddBddXorExistAbstractRecur(manager, fv, gv, Cube);
if (t == NULL) return(NULL);
/* Special case: 1 OR anything = 1. Hence, no need to compute
** the else branch if t is 1.
*/
if (t == one && topcube == top) {
cuddCacheInsert(manager, DD_BDD_XOR_EXIST_ABSTRACT_TAG, f, g, cube, one);
return(one);
}
cuddRef(t);
e = cuddBddXorExistAbstractRecur(manager, fnv, gnv, Cube);
if (e == NULL) {
Cudd_IterDerefBdd(manager, t);
return(NULL);
}
cuddRef(e);
if (topcube == top) { /* abstract */
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_IterDerefBdd(manager, t);
Cudd_IterDerefBdd(manager, e);
cuddDeref(r);
} else if (t == e) {
r = t;
cuddDeref(t);
cuddDeref(e);
} else {
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);
}
cuddCacheInsert(manager, DD_BDD_XOR_EXIST_ABSTRACT_TAG, f, g, cube, r);
return (r);
} /* end of cuddBddXorExistAbstractRecur */
/**Function********************************************************************
Synopsis [Performs the recursive steps of Cudd_bddExistAbstract.]
Description [Performs the recursive steps of Cudd_bddExistAbstract.
Returns the BDD obtained by abstracting the variables
of cube from f if successful; NULL otherwise. It is also used by
Cudd_bddUnivAbstract.]
SideEffects [None]
SeeAlso [Cudd_bddExistAbstract Cudd_bddUnivAbstract]
******************************************************************************/
DdNode *
cuddBddExistAbstractRecur(
DdManager * manager,
DdNode * f,
DdNode * cube)
{
DdNode *F, *T, *E, *res, *res1, *res2, *one;
statLine(manager);
one = DD_ONE(manager);
F = Cudd_Regular(f);
/* Cube is guaranteed to be a cube at this point. */
if (cube == one || F == one) {
return(f);
}
/* From now on, f and cube are non-constant. */
/* Abstract a variable that does not appear in f. */
while (manager->perm[F->index] > manager->perm[cube->index]) {
cube = cuddT(cube);
if (cube == one) return(f);
}
/* Check the cache. */
if (F->ref != 1 && (res = cuddCacheLookup2(manager, Cudd_bddExistAbstract, f, cube)) != NULL) {
return(res);
}
/* Compute the cofactors of f. */
T = cuddT(F); E = cuddE(F);
if (f != F) {
T = Cudd_Not(T); E = Cudd_Not(E);
}
/* If the two indices are the same, so are their levels. */
if (F->index == cube->index) {
if (T == one || E == one || T == Cudd_Not(E)) {
return(one);
}
res1 = cuddBddExistAbstractRecur(manager, T, cuddT(cube));
if (res1 == NULL) return(NULL);
if (res1 == one) {
if (F->ref != 1)
cuddCacheInsert2(manager, Cudd_bddExistAbstract, f, cube, one);
return(one);
}
cuddRef(res1);
res2 = cuddBddExistAbstractRecur(manager, E, cuddT(cube));
if (res2 == NULL) {
Cudd_IterDerefBdd(manager,res1);
return(NULL);
}
cuddRef(res2);
res = cuddBddAndRecur(manager, Cudd_Not(res1), Cudd_Not(res2));
if (res == NULL) {
Cudd_IterDerefBdd(manager, res1);
Cudd_IterDerefBdd(manager, res2);
return(NULL);
}
res = Cudd_Not(res);
cuddRef(res);
Cudd_IterDerefBdd(manager, res1);
Cudd_IterDerefBdd(manager, res2);
if (F->ref != 1)
cuddCacheInsert2(manager, Cudd_bddExistAbstract, f, cube, res);
cuddDeref(res);
return(res);
} else { /* if (cuddI(manager,F->index) < cuddI(manager,cube->index)) */
res1 = cuddBddExistAbstractRecur(manager, T, cube);
if (res1 == NULL) return(NULL);
cuddRef(res1);
res2 = cuddBddExistAbstractRecur(manager, E, cube);
if (res2 == NULL) {
Cudd_IterDerefBdd(manager, res1);
return(NULL);
}
cuddRef(res2);
/* ITE takes care of possible complementation of res1 and of the
** case in which res1 == res2. */
res = cuddBddIteRecur(manager, manager->vars[F->index], res1, res2);
if (res == NULL) {
Cudd_IterDerefBdd(manager, res1);
Cudd_IterDerefBdd(manager, res2);
return(NULL);
}
cuddDeref(res1);
cuddDeref(res2);
if (F->ref != 1)
cuddCacheInsert2(manager, Cudd_bddExistAbstract, f, cube, res);
return(res);
}
} /* end of cuddBddExistAbstractRecur */