private static boolean areExchangeable(Term a, Term b, Iterable<DefaultRule> rules) {
Map<Term, Term> substitution = new HashMap<Term, Term>();
substitution.put(a, b);
substitution.put(b, a);
Counters<DefaultRule> substitutedMultiset = new Counters<DefaultRule>();
for (DefaultRule rule : rules) {
DefaultRule defaultRule = substitute(rule, substitution);
for (DefaultRule rule2 : rules) {
if (isomorphic(rule2, defaultRule)) {
defaultRule = rule2;
}
}
substitutedMultiset.increment(defaultRule);
}
for (DefaultRule rule : rules) {
if (substitutedMultiset.decrementPre(rule) < 0) {
return false;
}
}
// outerLoop: for (DefaultRule rule : rules){
// if (rule.antecedent().terms().contains(a) || rule.consequent().terms().contains(a)
// ||
// rule.antecedent().terms().contains(b) ||
// rule.consequent().terms().contains(b)) {
// DefaultRule newDefault = substitute(rule, substitution);
// for (DefaultRule rule2 : rules) {
// if (isomorphic(rule2, newDefault)) {
// continue outerLoop;
// }
// }
// return false;
// }
// }
return true;
}
private static MultiList<Object, Set<Constant>> partitionExchangeable_impl(
Iterable<DefaultRule> rules) {
MultiMap<Term, Term> partitioning = new MultiMap<Term, Term>();
List<Term> constants = Sugar.arrayListFromCollections(constants(rules));
Set<Term> closed = new HashSet<Term>();
// checking interchangeability pairwise
for (int i = 0; i < constants.size(); i++) {
if (!closed.contains(constants.get(i))) {
partitioning.put(constants.get(i), constants.get(i));
for (int j = i + 1; j < constants.size(); j++) {
if (areExchangeable(constants.get(i), constants.get(j), rules)) {
partitioning.put(constants.get(i), constants.get(j));
closed.add(constants.get(j));
}
}
}
}
Map<Constant, Constant> map = new HashMap<Constant, Constant>();
for (Map.Entry<Term, Set<Term>> entry : partitioning.entrySet()) {
Constant lexmin = null;
for (Term t : entry.getValue()) {
if (t instanceof Constant) {
if (lexmin == null || t.toString().compareTo(lexmin.toString()) < 0) {
lexmin = (Constant) t;
}
}
}
for (Term t : entry.getValue()) {
if (t instanceof Constant) {
map.put((Constant) t, lexmin);
}
}
}
MultiMap<Pair<Object, Constant>, Constant> mm =
new MultiMap<Pair<Object, Constant>, Constant>();
for (Map.Entry<Constant, Constant> entry : map.entrySet()) {
mm.put(
new Pair<Object, Constant>(
entry.getValue().type() == null ? Sugar.NIL : entry.getValue().type(),
entry.getValue()),
entry.getKey());
}
MultiList<Object, Set<Constant>> retVal = new MultiList<Object, Set<Constant>>();
for (Map.Entry<Pair<Object, Constant>, Set<Constant>> entry : mm.entrySet()) {
retVal.put(entry.getKey().r, entry.getValue());
}
return retVal;
}
public static Triple<Set<DefaultRule>, Set<Clause>, List<Set<Constant>>> preprocessConstants(
Collection<DefaultRule> rules,
Collection<Clause> hardRules,
List<Set<Constant>> interchangeable) {
final Map<Term, Term> typedConstants = new HashMap<Term, Term>();
List<Set<Constant>> retInterchangeable = new ArrayList<Set<Constant>>();
for (Set<Constant> set : interchangeable) {
String type = min(set).name();
Set<Constant> newSet = new HashSet<Constant>();
for (Constant c : set) {
Constant typedConstant = Constant.construct(c.name(), type);
typedConstants.put(c, typedConstant);
newSet.add(typedConstant);
}
retInterchangeable.add(newSet);
}
Collection<DefaultRule> retDefaultRules =
Sugar.funcall(
rules,
new Sugar.Fun<DefaultRule, DefaultRule>() {
@Override
public DefaultRule apply(DefaultRule defaultRule) {
return DefaultTransformationUtils.substitute(defaultRule, typedConstants);
}
});
Collection<Clause> retHardRules =
Sugar.funcall(
hardRules,
new Sugar.Fun<Clause, Clause>() {
@Override
public Clause apply(Clause hardRule) {
return LogicUtils.substitute(hardRule, typedConstants);
}
});
return new Triple<Set<DefaultRule>, Set<Clause>, List<Set<Constant>>>(
Sugar.setFromCollections(retDefaultRules),
Sugar.setFromCollections(retHardRules),
Sugar.listFromCollections(retInterchangeable));
}
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;
}