public static boolean isomorphic(DefaultRule a, DefaultRule b) {
a = preprocess(a);
b = preprocess(b);
Matching m = new Matching();
Clause ca = new Clause(Sugar.iterable(a.antecedent().literals(), a.consequent().literals()));
Clause cb = new Clause(Sugar.iterable(b.antecedent().literals(), b.consequent().literals()));
return ca.variables().size() == cb.variables().size()
&& ca.literals().size() == cb.literals().size()
&& m.isomorphism(ca, cb);
}
public static Set<DefaultRule> selectNonisomorphicDefaultRules(
Iterable<DefaultRule> defaultRules) {
List<Clause> candidates = new ArrayList<Clause>();
for (DefaultRule rule : defaultRules) {
DefaultRule preprocessed = preprocess(rule);
candidates.add(
new Clause(
Sugar.<Literal>iterable(
preprocessed.antecedent().literals(), preprocessed.consequent().literals())));
}
Matching m = new Matching();
Set<DefaultRule> retVal = new HashSet<DefaultRule>();
for (Clause c : m.nonisomorphic(candidates)) {
List<Literal> head = new ArrayList<Literal>();
List<Literal> body = new ArrayList<Literal>();
for (Literal l : c.literals()) {
Literal newLiteral =
new Literal(
l.predicate().substring(l.predicate().indexOf(":") + 1), l.isNegated(), l.arity());
for (int i = 0; i < l.arity(); i++) {
newLiteral.set(l.get(i), i);
}
if (l.predicate().startsWith("antecedent:")
|| l.predicate().startsWith(SymmetricPredicates.PREFIX + "antecedent:")) {
body.add(newLiteral);
} else {
head.add(newLiteral);
}
}
retVal.add(new DefaultRule(new Clause(body), new Clause(head)));
}
return retVal;
}
private static Clause preprocessClause(Clause c, String prefix) {
List<Literal> newLiterals = new ArrayList<Literal>();
int specialID = 0;
for (Literal l : c.literals()) {
String predicate = l.predicate();
if (predicate.equals(SpecialBinaryPredicates.NEQ)
|| predicate.equals(SpecialBinaryPredicates.EQ)
|| predicate.equals(SpecialVarargPredicates.ALLDIFF)) {
predicate = SymmetricPredicates.PREFIX + prefix + predicate;
} else {
predicate = prefix + predicate;
}
Literal newLit = new Literal(predicate, l.isNegated(), l.arity());
for (int i = 0; i < l.arity(); i++) {
newLit.set(l.get(i), i);
}
newLiterals.add(newLit);
}
return new Clause(newLiterals);
}
public static MultiMap<DefaultRule, DefaultRule> representativeBodySpecializations(
DefaultRule rule, List<Set<Constant>> interchangeableConstants) {
Clause body = rule.antecedent();
Clause head = rule.consequent();
final MultiMap<Variable, Variable> different = surelyDifferent(rule);
final List<Variable> variables = Sugar.<Variable>listFromCollections(body.variables());
List<Integer> indices = VectorUtils.toList(VectorUtils.sequence(0, variables.size() - 1));
List<Tuple<Integer>> unifications =
Combinatorics.<Integer>cartesianPower(
indices,
indices.size(),
new Sugar.Fun<Tuple<Integer>, Boolean>() {
@Override
public Boolean apply(Tuple<Integer> integerTuple) {
for (int i = 0; i < integerTuple.size(); i++) {
if (integerTuple.get(i) > i
|| !integerTuple.get(i).equals(integerTuple.get(integerTuple.get(i)))
|| different
.get(variables.get(integerTuple.get(i)))
.contains(variables.get(i))
|| !sameType(variables.get(integerTuple.get(i)), variables.get(i))) {
return Boolean.FALSE;
}
}
return Boolean.TRUE;
}
});
Set<DefaultRule> nonIsomorphicUnifications = new HashSet<DefaultRule>();
for (Tuple<Integer> unification : unifications) {
Map<Term, Term> substitution = new HashMap<Term, Term>();
for (int i = 0; i < unification.size(); i++) {
substitution.put(variables.get(i), variables.get(unification.get(i)));
}
Clause newBody = LogicUtils.substitute(rule.antecedent(), substitution);
Clause newHead = LogicUtils.substitute(rule.consequent(), substitution);
nonIsomorphicUnifications.add(
new DefaultRule(
newBody.variables().size() > 1
? new Clause(Sugar.union(newBody.literals(), allDiffLiteral(newBody)))
: newBody,
newHead));
}
nonIsomorphicUnifications =
DefaultTransformationUtils.selectNonisomorphicDefaultRules(nonIsomorphicUnifications);
MultiMap<DefaultRule, DefaultRule> retVal = new MultiMap<DefaultRule, DefaultRule>();
// this needs to be improved... e.g. using typing information...
MultiList<Integer, Constant> consts = new MultiList<Integer, Constant>();
int index = 0;
for (Set<Constant> interch : interchangeableConstants) {
consts.putAll(index++, interch);
}
for (DefaultRule unifiedRule : nonIsomorphicUnifications) {
List<Variable> unifsVariables = Sugar.listFromCollections(unifiedRule.variables());
if (unifsVariables.isEmpty()) {
retVal.put(unifiedRule, unifiedRule);
} else {
Set<DefaultRule> substituted = new HashSet<DefaultRule>();
middleLoop:
for (Tuple<Integer> tuple :
Combinatorics.cartesianPower(
new NaturalNumbersList(0, interchangeableConstants.size()),
unifsVariables.size())) {
Counters<Integer> used = new Counters<Integer>();
Map<Term, Term> substitution = new HashMap<Term, Term>();
for (int i = 0; i < unifsVariables.size(); i++) {
int j = used.incrementPost(tuple.get(i));
if (j >= consts.get(tuple.get(i)).size()) {
continue middleLoop;
} else {
if (unifsVariables.get(i).type() == null) {
substitution.put(
unifsVariables.get(i),
Variable.construct(
unifsVariables.get(i).name(), consts.get(tuple.get(i)).get(j).type()));
} else {
if (unifsVariables.get(i).type().equals(consts.get(tuple.get(i)).get(j).type())) {
substitution.put(
unifsVariables.get(i),
Variable.construct(
unifsVariables.get(i).name(), consts.get(tuple.get(i)).get(j).type()));
} else {
continue middleLoop;
}
}
}
}
substituted.add(DefaultTransformationUtils.substitute(unifiedRule, substitution));
}
retVal.putAll(
unifiedRule, DefaultTransformationUtils.selectNonisomorphicDefaultRules(substituted));
}
}
return retVal;
}