/**Function********************************************************************
Synopsis [Implementation of Rudell's sifting algorithm.]
Description [Implementation of Rudell's sifting algorithm.
Assumes that no dead nodes are present.
<ol>
<li> Order all the variables according to the number of entries
in each unique table.
<li> Sift the variable up and down, remembering each time the
total size of the DD heap.
<li> Select the best permutation.
<li> Repeat 3 and 4 for all variables.
</ol>
Returns 1 if successful; 0 otherwise.]
SideEffects [None]
SeeAlso []
******************************************************************************/
int
cuddZddSifting(
DdManager * table,
int lower,
int upper)
{
int i;
int *var;
int size;
int x;
int result;
#ifdef DD_STATS
int previousSize;
#endif
size = table->sizeZ;
/* Find order in which to sift variables. */
var = NULL;
zdd_entry = ALLOC(int, size);
if (zdd_entry == NULL) {
table->errorCode = CUDD_MEMORY_OUT;
goto cuddZddSiftingOutOfMem;
}
var = ALLOC(int, size);
if (var == NULL) {
table->errorCode = CUDD_MEMORY_OUT;
goto cuddZddSiftingOutOfMem;
}
for (i = 0; i < size; i++) {
x = table->permZ[i];
zdd_entry[i] = table->subtableZ[x].keys;
var[i] = i;
}
qsort((void *)var, size, sizeof(int), (int (*)(const void *, const void *))cuddZddUniqueCompare);
/* Now sift. */
for (i = 0; i < ddMin(table->siftMaxVar, size); i++) {
if (zddTotalNumberSwapping >= table->siftMaxSwap)
break;
x = table->permZ[var[i]];
if (x < lower || x > upper) continue;
#ifdef DD_STATS
previousSize = table->keysZ;
#endif
result = cuddZddSiftingAux(table, x, lower, upper);
if (!result)
goto cuddZddSiftingOutOfMem;
#ifdef DD_STATS
if (table->keysZ < (unsigned) previousSize) {
(void) fprintf(table->out,"-");
} else if (table->keysZ > (unsigned) previousSize) {
(void) fprintf(table->out,"+"); /* should never happen */
(void) fprintf(table->out,"\nSize increased from %d to %d while sifting variable %d\n", previousSize, table->keysZ , var[i]);
} else {
(void) fprintf(table->out,"=");
}
fflush(table->out);
#endif
}
FREE(var);
FREE(zdd_entry);
return(1);
cuddZddSiftingOutOfMem:
if (zdd_entry != NULL) FREE(zdd_entry);
if (var != NULL) FREE(var);
return(0);
} /* end of cuddZddSifting */
/**
@brief Implementation of Rudell's sifting algorithm.
@details Assumes that no dead nodes are present.
<ol>
<li> Order all the variables according to the number of entries
in each unique table.
<li> Sift the variable up and down, remembering each time the
total size of the %DD heap.
<li> Select the best permutation.
<li> Repeat 3 and 4 for all variables.
</ol>
@return 1 if successful; 0 otherwise.
@sideeffect None
*/
int
cuddZddSifting(
DdManager * table,
int lower,
int upper)
{
int i;
IndexKey *var;
int size;
int x;
int result;
#ifdef DD_STATS
int previousSize;
#endif
size = table->sizeZ;
/* Find order in which to sift variables. */
var = ALLOC(IndexKey, size);
if (var == NULL) {
table->errorCode = CUDD_MEMORY_OUT;
goto cuddZddSiftingOutOfMem;
}
for (i = 0; i < size; i++) {
x = table->permZ[i];
var[i].index = i;
var[i].keys = table->subtableZ[x].keys;
}
util_qsort(var, size, sizeof(IndexKey), cuddZddUniqueCompare);
/* Now sift. */
for (i = 0; i < ddMin(table->siftMaxVar, size); i++) {
if (table->zddTotalNumberSwapping >= table->siftMaxSwap)
break;
if (util_cpu_time() - table->startTime > table->timeLimit) {
table->autoDynZ = 0; /* prevent further reordering */
break;
}
if (table->terminationCallback != NULL &&
table->terminationCallback(table->tcbArg)) {
table->autoDynZ = 0; /* prevent further reordering */
break;
}
x = table->permZ[var[i].index];
if (x < lower || x > upper) continue;
#ifdef DD_STATS
previousSize = table->keysZ;
#endif
result = cuddZddSiftingAux(table, x, lower, upper);
if (!result)
goto cuddZddSiftingOutOfMem;
#ifdef DD_STATS
if (table->keysZ < (unsigned) previousSize) {
(void) fprintf(table->out,"-");
} else if (table->keysZ > (unsigned) previousSize) {
(void) fprintf(table->out,"+"); /* should never happen */
(void) fprintf(table->out,"\nSize increased from %d to %d while sifting variable %d\n", previousSize, table->keysZ , var[i].index);
} else {
(void) fprintf(table->out,"=");
}
fflush(table->out);
#endif
}
FREE(var);
return(1);
cuddZddSiftingOutOfMem:
if (var != NULL) FREE(var);
return(0);
} /* end of cuddZddSifting */
