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Unique abstraction reference
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/** | |
* @brief Unique abstraction implementation. | |
* | |
* This implementation includes some optimizations from Meolic's proposal. | |
* However, it does make the recursive calls before combining the results | |
* with the ITE operator. | |
*/ | |
DdNode *uniqueAbstractRec(DdManager *home, DdNode *f, DdNode *cube) { | |
// satLine(home) | |
uniqueStats.recursiveCalls++; | |
DdNode *one = Cudd_ReadOne(home); | |
DdNode *zero = Cudd_Not(one); | |
DdNode *F = Cudd_Regular(f); | |
if (cube == one) // Base case 1: Cube is exhausted | |
return f; | |
if (Cudd_IsConstant(f)) // Base case 2: f is a terminal | |
return zero; | |
// From now on f is not constant | |
int topf = var2level(home, f); | |
int topc = var2level(home, cube); | |
if (topc < topf) { // Variable in cube is a don't care in f | |
uniqueStats.varAbstracted++; | |
return zero; | |
} | |
// Check the cache | |
if (F->ref != 1) { | |
DdNode *result = cuddCacheLookup2(home, uniqueAbstract, f, cube); | |
if (result != NULL) { | |
uniqueStats.cacheHits++; | |
return result; | |
} | |
} | |
DdNode *T = Cudd_T(F); | |
DdNode *E = Cudd_E(F); | |
if (f != F) { | |
T = Cudd_Not(T); | |
E = Cudd_Not(E); | |
} | |
if (topf == topc) { | |
uniqueStats.abstract++; | |
if (E == zero) { | |
uniqueStats.abstractSimple++; | |
DdNode *res = uniqueAbstractRec(home, T, Cudd_T(cube)); | |
if (res == NULL) | |
return NULL; | |
if (F->ref != 1) | |
cuddCacheInsert2(home, uniqueAbstract, f, cube, res); | |
return res; | |
} else if (T == zero) { | |
uniqueStats.abstractSimple++; | |
DdNode *res = uniqueAbstractRec(home, E, Cudd_T(cube)); | |
if (res == NULL) | |
return NULL; | |
if (F->ref != 1) | |
cuddCacheInsert2(home, uniqueAbstract, f, cube, res); | |
return res; | |
} else { | |
uniqueStats.abstractComplex++; | |
DdNode *EX = cuddBddExistAbstractRecur(home, E, Cudd_T(cube)); | |
if (EX == NULL) { | |
return NULL; | |
} | |
Cudd_Ref(EX); | |
uniqueStats.existAbstract++; | |
DdNode *TX = cuddBddExistAbstractRecur(home, T, Cudd_T(cube)); | |
if (TX == NULL) { | |
Cudd_IterDerefBdd(home, EX); | |
return NULL; | |
} | |
Cudd_Ref(TX); | |
uniqueStats.existAbstract++; | |
if (EX == TX) { | |
Cudd_IterDerefBdd(home, EX); | |
Cudd_IterDerefBdd(home, TX); | |
if (F->ref != 1) | |
cuddCacheInsert2(home, uniqueAbstract, f, cube, zero); | |
return zero; | |
} | |
// This is the really complex case | |
DdNode *resultThen; // resultThen = uniqueThen /\ ~EX | |
{ | |
DdNode *uniqueThen = uniqueAbstractRec(home, T, Cudd_T(cube)); | |
if (uniqueThen == NULL) | |
return NULL; | |
Cudd_Ref(uniqueThen); | |
// resultThen = cuddBddAndRecur(home, uniqueThen, Cudd_Not(EX)); | |
resultThen = | |
cuddBddIteRecur(home, EX, zero, uniqueThen); // ITE(F,0,H) = !F * H | |
if (resultThen == NULL) { | |
Cudd_IterDerefBdd(home, uniqueThen); | |
return NULL; | |
} | |
Cudd_Ref(resultThen); | |
Cudd_IterDerefBdd(home, uniqueThen); | |
Cudd_IterDerefBdd(home, EX); | |
} | |
DdNode *resultElse; // resultElse = uniqueElse /\ ~TX | |
{ | |
DdNode *uniqueElse = uniqueAbstractRec(home, E, Cudd_T(cube)); | |
if (uniqueElse == NULL) { | |
Cudd_IterDerefBdd(home, resultThen); | |
Cudd_IterDerefBdd(home, TX); | |
return NULL; | |
} | |
Cudd_Ref(uniqueElse); | |
// resultElse = cuddBddAndRecur(home, uniqueElse, Cudd_Not(TX)); | |
resultElse = | |
cuddBddIteRecur(home, TX, zero, uniqueElse); // ITE(F,0,H) = !F * H | |
if (resultElse == NULL) { | |
Cudd_IterDerefBdd(home, resultThen); | |
Cudd_IterDerefBdd(home, TX); | |
Cudd_IterDerefBdd(home, uniqueElse); | |
return NULL; | |
} | |
Cudd_Ref(resultElse); | |
Cudd_IterDerefBdd(home, TX); | |
Cudd_IterDerefBdd(home, uniqueElse); | |
} | |
DdNode *result = cuddBddIteRecur(home, resultThen, one, | |
resultElse); // ITE(F,1,H) = F + H | |
// DdNode* result = | |
// cuddBddAndRecur(home, Cudd_Not(resultThen), Cudd_Not(resultElse)); | |
if (result == NULL) { | |
Cudd_IterDerefBdd(home, resultThen); | |
Cudd_IterDerefBdd(home, resultElse); | |
return NULL; | |
} | |
// The folowing is required if cuddBddAndRecur is used to compute the or. | |
// result = Cudd_Not(result); // result = resultThen \/ resultElse | |
Cudd_Ref(result); | |
Cudd_IterDerefBdd(home, resultThen); | |
Cudd_IterDerefBdd(home, resultElse); | |
if (F->ref != 1) { | |
cuddCacheInsert2(home, uniqueAbstract, f, cube, result); | |
} | |
Cudd_Deref(result); | |
return result; | |
} | |
} else { | |
uniqueStats.nonAbstract++; | |
DdNode *uniqueThen = uniqueAbstractRec(home, T, cube); | |
if (uniqueThen == NULL) | |
return NULL; | |
Cudd_Ref(uniqueThen); | |
DdNode *uniqueElse = uniqueAbstractRec(home, E, cube); | |
if (uniqueElse == NULL) { | |
Cudd_IterDerefBdd(home, uniqueThen); | |
return NULL; | |
} | |
Cudd_Ref(uniqueElse); | |
DdNode *result = | |
cuddBddIteRecur(home, topVar(home, F), uniqueThen, uniqueElse); | |
if (result == NULL) { | |
Cudd_IterDerefBdd(home, uniqueThen); | |
Cudd_IterDerefBdd(home, uniqueElse); | |
return NULL; | |
} | |
Cudd_Deref(uniqueThen); | |
Cudd_Deref(uniqueElse); | |
if (F->ref != 1) | |
cuddCacheInsert2(home, uniqueAbstract, f, cube, result); | |
return result; | |
} | |
} |
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