Examples with Atom at.ac.tuwien.kr.alpha.api.programs.atoms.Atom used on opensource projects

Example 36 with Atom

use of at.ac.tuwien.kr.alpha.api.programs.atoms.Atom in project Alpha by alpha-asp.

the class NaiveGrounder method getRulesWithUniqueHead.

private Set<CompiledRule> getRulesWithUniqueHead() {
    // FIXME: below optimisation (adding support nogoods if there is only one rule instantiation per unique atom over the interpretation) could
    // be done as a transformation (adding a non-ground constraint corresponding to the nogood that is generated by the grounder).
    // Record all unique rule heads.
    final Set<CompiledRule> uniqueGroundRulePerGroundHead = new HashSet<>();
    for (Map.Entry<Predicate, LinkedHashSet<CompiledRule>> headDefiningRules : program.getPredicateDefiningRules().entrySet()) {
        if (headDefiningRules.getValue().size() != 1) {
            continue;
        }
        CompiledRule nonGroundRule = headDefiningRules.getValue().iterator().next();
        // Check that all variables of the body also occur in the head (otherwise grounding is not unique).
        Atom headAtom = nonGroundRule.getHeadAtom();
        // Rule is not guaranteed unique if there are facts for it.
        HashSet<Instance> potentialFacts = factsFromProgram.get(headAtom.getPredicate());
        if (potentialFacts != null && !potentialFacts.isEmpty()) {
            continue;
        }
        // Collect head and body variables.
        HashSet<VariableTerm> occurringVariablesHead = new HashSet<>(headAtom.toLiteral().getBindingVariables());
        HashSet<VariableTerm> occurringVariablesBody = new HashSet<>();
        for (Literal lit : nonGroundRule.getPositiveBody()) {
            occurringVariablesBody.addAll(lit.getBindingVariables());
        }
        occurringVariablesBody.removeAll(occurringVariablesHead);
        // Check if ever body variables occurs in the head.
        if (occurringVariablesBody.isEmpty()) {
            uniqueGroundRulePerGroundHead.add(nonGroundRule);
        }
    }
    return uniqueGroundRulePerGroundHead;
}

Example 37 with Atom

use of at.ac.tuwien.kr.alpha.api.programs.atoms.Atom in project Alpha by alpha-asp.

the class SimpleAnswerSetFormatter method format.

@Override
public String format(AnswerSet answerSet) {
    List<String> predicateInstanceStrings = new ArrayList<>();
    for (Predicate p : answerSet.getPredicates()) {
        SortedSet<Atom> instances;
        if ((instances = answerSet.getPredicateInstances(p)) == null || instances.isEmpty()) {
            predicateInstanceStrings.add(p.getName());
        } else {
            List<String> atomStrings = instances.stream().map((atom) -> atom.toString()).collect(Collectors.toList());
            predicateInstanceStrings.add(String.join(this.atomSeparator, atomStrings));
        }
    }
    return "{ " + String.join(this.atomSeparator, predicateInstanceStrings) + " }";
}

Example 38 with Atom

use of at.ac.tuwien.kr.alpha.api.programs.atoms.Atom in project Alpha by alpha-asp.

the class AnswerSetQueryTest method matchXWithFuncTerm.

@Test
public void matchXWithFuncTerm() {
    Predicate p = Predicates.getPredicate("p", 2);
    Atom a1 = Atoms.newBasicAtom(p, Terms.newSymbolicConstant("x"), Terms.newFunctionTerm("f", Terms.newSymbolicConstant("x")));
    Atom a2 = Atoms.newBasicAtom(p, Terms.newSymbolicConstant("y"), Terms.newFunctionTerm("f", Terms.newSymbolicConstant("y")));
    Atom a3 = Atoms.newBasicAtom(p, Terms.newSymbolicConstant("y"), Terms.newFunctionTerm("f", Terms.newSymbolicConstant("x")));
    Atom a4 = Atoms.newBasicAtom(p, Terms.newSymbolicConstant("x"), Terms.newFunctionTerm("f", Terms.newSymbolicConstant("y")));
    Atom a5 = Atoms.newBasicAtom(p, Terms.newSymbolicConstant("x"), Terms.newFunctionTerm("f"));
    SortedSet<Predicate> predicates = new TreeSet<>();
    predicates.add(p);
    Map<Predicate, SortedSet<Atom>> instances = new HashMap<>();
    SortedSet<Atom> ps = new TreeSet<>();
    ps.add(a1);
    ps.add(a2);
    ps.add(a3);
    ps.add(a4);
    ps.add(a5);
    instances.put(p, ps);
    AnswerSet as = AnswerSets.newAnswerSet(predicates, instances);
    AnswerSetQueryImpl query = AnswerSetQueryImpl.forPredicate(Predicates.getPredicate("p", 2)).withConstantEquals(0, "x").withFunctionTerm(1, "f", 1);
    List<Atom> queryResult = as.query(query);
    assertEquals(2, queryResult.size());
}

Example 39 with Atom

use of at.ac.tuwien.kr.alpha.api.programs.atoms.Atom in project Alpha by alpha-asp.

the class AnswerSetQueryTest method matchEvenIntegers.

@Test
public void matchEvenIntegers() {
    AnswerSetBuilder bld = new AnswerSetBuilder();
    bld.predicate("p").instance(1).instance(2).instance(3).instance(4).instance(5).instance("bla").symbolicInstance("blubb");
    AnswerSet as = bld.build();
    java.util.function.Predicate<Term> isInteger = (term) -> {
        if (!(term instanceof ConstantTerm<?>)) {
            return false;
        }
        String strValue = ((ConstantTerm<?>) term).getObject().toString();
        return strValue.matches("[0-9]+");
    };
    AnswerSetQueryImpl evenIntegers = AnswerSetQueryImpl.forPredicate(Predicates.getPredicate("p", 1)).withFilter(0, isInteger.and((term) -> Integer.valueOf(((ConstantTerm<?>) term).getObject().toString()) % 2 == 0));
    List<Atom> queryResult = as.query(evenIntegers);
    assertEquals(2, queryResult.size());
    for (Atom atom : queryResult) {
        ConstantTerm<?> term = (ConstantTerm<?>) atom.getTerms().get(0);
        assertTrue(Integer.valueOf(term.getObject().toString()) % 2 == 0);
    }
}

Example 40 with Atom

use of at.ac.tuwien.kr.alpha.api.programs.atoms.Atom in project Alpha by alpha-asp.

the class AnswerSetQueryTest method matchPredicate.

@Test
public void matchPredicate() {
    AnswerSetBuilder bld = new AnswerSetBuilder();
    // @formatter:off
    bld.predicate("p").symbolicInstance("a").symbolicInstance("b").predicate("q").symbolicInstance("x");
    // @formatter:on
    AnswerSet as = bld.build();
    List<Atom> queryResult = as.query(AnswerSetQueryImpl.forPredicate(Predicates.getPredicate("p", 1)));
    assertEquals(2, queryResult.size());
    for (Atom a : queryResult) {
        assertTrue(a.getPredicate().equals(Predicates.getPredicate("p", 1)));
    }
}