src/bdd/cudd/cuddAddInv.c

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#include "util_hack.h"
#include "cuddInt.h"


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/* Constant declarations                                                     */
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/* Stucture declarations                                                     */
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/* Type declarations                                                         */
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#ifndef lint
static char rcsid[] DD_UNUSED = "$Id: cuddAddInv.c,v 1.1.1.1 2003/02/24 22:23:50 wjiang Exp $";
#endif


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/* Macro declarations                                                        */
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/* Static function prototypes                                                */
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/* Definition of exported functions                                          */
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DdNode *
Cudd_addScalarInverse(
  DdManager * dd,
  DdNode * f,
  DdNode * epsilon)
{
    DdNode *res;

    if (!cuddIsConstant(epsilon)) {
        (void) fprintf(dd->err,"Invalid epsilon\n");
        return(NULL);
    }
    do {
        dd->reordered = 0;
        res  = cuddAddScalarInverseRecur(dd,f,epsilon);
    } while (dd->reordered == 1);
    return(res);

} /* end of Cudd_addScalarInverse */

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/* Definition of internal functions                                          */
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DdNode *
cuddAddScalarInverseRecur(
  DdManager * dd,
  DdNode * f,
  DdNode * epsilon)
{
    DdNode *t, *e, *res;
    CUDD_VALUE_TYPE value;

    statLine(dd);
    if (cuddIsConstant(f)) {
        if (ddAbs(cuddV(f)) < cuddV(epsilon)) return(NULL);
        value = 1.0 / cuddV(f);
        res = cuddUniqueConst(dd,value);
        return(res);
    }

    res = cuddCacheLookup2(dd,Cudd_addScalarInverse,f,epsilon);
    if (res != NULL) return(res);

    t = cuddAddScalarInverseRecur(dd,cuddT(f),epsilon);
    if (t == NULL) return(NULL);
    cuddRef(t);

    e = cuddAddScalarInverseRecur(dd,cuddE(f),epsilon);
    if (e == NULL) {
        Cudd_RecursiveDeref(dd, t);
        return(NULL);
    }
    cuddRef(e);

    res = (t == e) ? t : cuddUniqueInter(dd,(int)f->index,t,e);
    if (res == NULL) {
        Cudd_RecursiveDeref(dd, t);
        Cudd_RecursiveDeref(dd, e);
        return(NULL);
    }

    cuddCacheInsert2(dd,Cudd_addScalarInverse,f,epsilon,res);

    return(res);

} /* end of cuddAddScalarInverseRecur */


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/* Definition of static functions                                            */
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