/**
* Constructs an ARCE strategy that will use the given translation log to relate the cnf clauses
* back to the logic constraints from which they were generated.
*
* @ensures this.hardnessCutOff' = hardnessCutOff and this.recycleLimit' = recycleLimit and
* this.noRecycleRatio' = noRecycleRatio
*/
public DynamicRCEStrategy(
final TranslationLog log, double noRecycleRatio, double hardnessCutOff, double recycleLimit) {
if (noRecycleRatio < 0 || noRecycleRatio > 1)
throw new IllegalArgumentException("noRecycleRatio must be in [0..1]: " + noRecycleRatio);
if (hardnessCutOff < 1)
throw new IllegalArgumentException("hardnessCutOff must be >=1: " + hardnessCutOff);
if (recycleLimit < 1)
throw new IllegalArgumentException("recycleLimit must be >=1: " + recycleLimit);
this.noRecycleRatio = noRecycleRatio;
this.hardnessCutOff = hardnessCutOff;
this.recycleLimit = recycleLimit;
this.hits = new TreeSequence<IntSet>();
for (IntIterator itr = StrategyUtils.rootVars(log).iterator(); itr.hasNext(); ) {
hits.put(itr.next(), null);
}
}
/**
* Returns an array R of longs such that for each i, j in [0..R.length) i < j implies that the
* formula identified by (int)R[i] in this.hits contributes fewer clauses to the core of the given
* trace than the formula identified by (int)R[j].
*
* @return an array as described above
*/
private long[] sortByRelevance(ResolutionTrace trace, IntSet relevantVars) {
hits.indices().retainAll(relevantVars);
if (hits.get(hits.indices().min()) == null) { // first call, initialize the hits
for (IntIterator varItr = relevantVars.iterator(); varItr.hasNext(); ) {
final int var = varItr.next();
final IntSet varReachable = new IntBitSet(var + 1);
varReachable.add(var);
hits.put(var, varReachable);
}
for (Iterator<Clause> clauseItr = trace.reverseIterator(trace.axioms());
clauseItr.hasNext(); ) {
final Clause clause = clauseItr.next();
final int maxVar = clause.maxVariable();
for (IntSet reachableVars : hits.values()) {
if (reachableVars.contains(maxVar)) {
for (IntIterator lits = clause.literals(); lits.hasNext(); ) {
reachableVars.add(StrictMath.abs(lits.next()));
}
}
}
}
}
final long[] counts = new long[hits.size()];
for (Iterator<Clause> clauseItr = trace.iterator(trace.core()); clauseItr.hasNext(); ) {
final Clause clause = clauseItr.next();
final int maxVar = clause.maxVariable();
int i = 0;
for (IntSet reachableVars : hits.values()) {
if (reachableVars.contains(maxVar)) {
counts[i]++;
}
i++;
}
}
int i = 0;
for (IntIterator varItr = hits.indices().iterator(); varItr.hasNext(); ) {
final int var = varItr.next();
counts[i] = (counts[i] << 32) | var;
i++;
}
Arrays.sort(counts);
return counts;
}