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Diffstat (limited to 'src/bdd/cudd/cuddBddAbs.c')
-rw-r--r-- | src/bdd/cudd/cuddBddAbs.c | 689 |
1 files changed, 689 insertions, 0 deletions
diff --git a/src/bdd/cudd/cuddBddAbs.c b/src/bdd/cudd/cuddBddAbs.c new file mode 100644 index 00000000..20a8f15a --- /dev/null +++ b/src/bdd/cudd/cuddBddAbs.c @@ -0,0 +1,689 @@ +/**CFile*********************************************************************** + + FileName [cuddBddAbs.c] + + PackageName [cudd] + + Synopsis [Quantification functions for BDDs.] + + Description [External procedures included in this module: + <ul> + <li> Cudd_bddExistAbstract() + <li> Cudd_bddXorExistAbstract() + <li> Cudd_bddUnivAbstract() + <li> Cudd_bddBooleanDiff() + <li> Cudd_bddVarIsDependent() + </ul> + Internal procedures included in this module: + <ul> + <li> cuddBddExistAbstractRecur() + <li> cuddBddXorExistAbstractRecur() + <li> cuddBddBooleanDiffRecur() + </ul> + Static procedures included in this module: + <ul> + <li> bddCheckPositiveCube() + </ul> + ] + + Author [Fabio Somenzi] + + Copyright [This file was created at the University of Colorado at + Boulder. The University of Colorado at Boulder makes no warranty + about the suitability of this software for any purpose. It is + presented on an AS IS basis.] + +******************************************************************************/ + +#include "util.h" +#include "cuddInt.h" + + +/*---------------------------------------------------------------------------*/ +/* Constant declarations */ +/*---------------------------------------------------------------------------*/ + + +/*---------------------------------------------------------------------------*/ +/* Stucture declarations */ +/*---------------------------------------------------------------------------*/ + + +/*---------------------------------------------------------------------------*/ +/* Type declarations */ +/*---------------------------------------------------------------------------*/ + + +/*---------------------------------------------------------------------------*/ +/* Variable declarations */ +/*---------------------------------------------------------------------------*/ + +#ifndef lint +static char rcsid[] DD_UNUSED = "$Id: cuddBddAbs.c,v 1.1.1.1 2003/02/24 22:23:51 wjiang Exp $"; +#endif + +/*---------------------------------------------------------------------------*/ +/* Macro declarations */ +/*---------------------------------------------------------------------------*/ + + +/**AutomaticStart*************************************************************/ + +/*---------------------------------------------------------------------------*/ +/* Static function prototypes */ +/*---------------------------------------------------------------------------*/ + +static int bddCheckPositiveCube ARGS((DdManager *manager, DdNode *cube)); + +/**AutomaticEnd***************************************************************/ + + +/*---------------------------------------------------------------------------*/ +/* Definition of exported functions */ +/*---------------------------------------------------------------------------*/ + + +/**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 otherwise.] + + SideEffects [None] + + SeeAlso [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); + + return(res); + +} /* end of Cudd_bddExistAbstract */ + + +/**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_bddUnivAbstract Cudd_bddExistAbstract Cudd_bddAndAbstract] + +******************************************************************************/ +DdNode * +Cudd_bddXorExistAbstract( + DdManager * manager, + DdNode * f, + DdNode * g, + 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 = cuddBddXorExistAbstractRecur(manager, f, g, cube); + } while (manager->reordered == 1); + + return(res); + +} /* end of Cudd_bddXorExistAbstract */ + + +/**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 [Computes the boolean difference of f with respect to x.] + + Description [Computes the boolean difference of f with respect to the + variable with index x. Returns the BDD of the boolean difference if + successful; NULL otherwise.] + + SideEffects [None] + + SeeAlso [] + +******************************************************************************/ +DdNode * +Cudd_bddBooleanDiff( + DdManager * manager, + DdNode * f, + int x) +{ + DdNode *res, *var; + + /* If the variable is not currently in the manager, f cannot + ** depend on it. + */ + if (x >= manager->size) return(Cudd_Not(DD_ONE(manager))); + var = manager->vars[x]; + + do { + manager->reordered = 0; + res = cuddBddBooleanDiffRecur(manager, Cudd_Regular(f), var); + } while (manager->reordered == 1); + + return(res); + +} /* end of Cudd_bddBooleanDiff */ + + +/**Function******************************************************************** + + Synopsis [Checks whether a variable is dependent on others in a + function.] + + Description [Checks whether a variable is dependent on others in a + function. Returns 1 if the variable is dependent; 0 otherwise. No + new nodes are created.] + + SideEffects [None] + + SeeAlso [] + +******************************************************************************/ +int +Cudd_bddVarIsDependent( + DdManager *dd, /* manager */ + DdNode *f, /* function */ + DdNode *var /* variable */) +{ + DdNode *F, *res, *zero, *ft, *fe; + unsigned topf, level; + DdNode *(*cacheOp)(DdManager *, DdNode *, DdNode *); + int retval; + + zero = Cudd_Not(DD_ONE(dd)); + if (Cudd_IsConstant(f)) return(f == zero); + + /* From now on f is not constant. */ + F = Cudd_Regular(f); + topf = (unsigned) dd->perm[F->index]; + level = (unsigned) dd->perm[var->index]; + + /* Check terminal case. If topf > index of var, f does not depend on var. + ** Therefore, var is not dependent in f. */ + if (topf > level) { + return(0); + } + + cacheOp = + (DdNode *(*)(DdManager *, DdNode *, DdNode *)) Cudd_bddVarIsDependent; + res = cuddCacheLookup2(dd,cacheOp,f,var); + if (res != NULL) { + return(res != zero); + } + + /* Compute cofactors. */ + ft = Cudd_NotCond(cuddT(F), f != F); + fe = Cudd_NotCond(cuddE(F), f != F); + + if (topf == level) { + retval = Cudd_bddLeq(dd,ft,Cudd_Not(fe)); + } else { + retval = Cudd_bddVarIsDependent(dd,ft,var) && + Cudd_bddVarIsDependent(dd,fe,var); + } + + cuddCacheInsert2(dd,cacheOp,f,var,Cudd_NotCond(zero,retval)); + + return(retval); + +} /* Cudd_bddVarIsDependent */ + + +/*---------------------------------------------------------------------------*/ +/* Definition of internal functions */ +/*---------------------------------------------------------------------------*/ + + +/**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 */ + + +/**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_bddBoleanDiff.] + + Description [Performs the recursive steps of Cudd_bddBoleanDiff. + Returns the BDD obtained by XORing the cofactors of f with respect to + var if successful; NULL otherwise. Exploits the fact that dF/dx = + dF'/dx.] + + SideEffects [None] + + SeeAlso [] + +******************************************************************************/ +DdNode * +cuddBddBooleanDiffRecur( + DdManager * manager, + DdNode * f, + DdNode * var) +{ + DdNode *T, *E, *res, *res1, *res2; + + statLine(manager); + if (cuddI(manager,f->index) > manager->perm[var->index]) { + /* f does not depend on var. */ + return(Cudd_Not(DD_ONE(manager))); + } + + /* From now on, f is non-constant. */ + + /* If the two indices are the same, so are their levels. */ + if (f->index == var->index) { + res = cuddBddXorRecur(manager, cuddT(f), cuddE(f)); + return(res); + } + + /* From now on, cuddI(manager,f->index) < cuddI(manager,cube->index). */ + + /* Check the cache. */ + res = cuddCacheLookup2(manager, cuddBddBooleanDiffRecur, f, var); + if (res != NULL) { + return(res); + } + + /* Compute the cofactors of f. */ + T = cuddT(f); E = cuddE(f); + + res1 = cuddBddBooleanDiffRecur(manager, T, var); + if (res1 == NULL) return(NULL); + cuddRef(res1); + res2 = cuddBddBooleanDiffRecur(manager, Cudd_Regular(E), var); + 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); + cuddCacheInsert2(manager, cuddBddBooleanDiffRecur, f, var, res); + return(res); + +} /* end of cuddBddBooleanDiffRecur */ + + +/*---------------------------------------------------------------------------*/ +/* Definition of static functions */ +/*---------------------------------------------------------------------------*/ + +/**Function******************************************************************** + + Synopsis [Checks whether cube is an BDD representing the product of + positive literals.] + + Description [Returns 1 in case of success; 0 otherwise.] + + SideEffects [None] + +******************************************************************************/ +static int +bddCheckPositiveCube( + DdManager * manager, + DdNode * cube) +{ + if (Cudd_IsComplement(cube)) return(0); + if (cube == DD_ONE(manager)) return(1); + if (cuddIsConstant(cube)) return(0); + if (cuddE(cube) == Cudd_Not(DD_ONE(manager))) { + return(bddCheckPositiveCube(manager, cuddT(cube))); + } + return(0); + +} /* end of bddCheckPositiveCube */ + |