Java Code Examples for kodkod.ast.Expression#arity()

/**
 * Add a new sig to this solution and associate it with the given expression
 * (and if s.isTopLevel then add this expression into Sig.UNIV). <br>
 * The expression must contain only constant Relations or Relations that are
 * already bound in this solution. <br>
 * (If the sig was already added by a previous call to addSig(), then this call
 * will return immediately without altering what it is associated with)
 */
void addSig(Sig s, Expression expr) throws ErrorFatal {
    if (solved)
        throw new ErrorFatal("Cannot add an additional sig since solve() has completed.");
    if (expr.arity() != 1)
        throw new ErrorFatal("Sig " + s + " must be associated with a unary relational value.");
    if (a2k.containsKey(s))
        return;
    a2k.put(s, expr);
    sigs.add(s);
    if (s.isTopLevel())
        a2k.put(UNIV, a2k.get(UNIV).union(expr));
}
 

/**
 * Add a new field to this solution and associate it with the given expression.
 * <br>
 * The expression must contain only constant Relations or Relations that are
 * already bound in this solution. <br>
 * (If the field was already added by a previous call to addField(), then this
 * call will return immediately without altering what it is associated with)
 */
void addField(Field f, Expression expr) throws ErrorFatal {
    if (solved)
        throw new ErrorFatal("Cannot add an additional field since solve() has completed.");
    if (expr.arity() != f.type().arity())
        throw new ErrorFatal("Field " + f + " must be associated with an " + f.type().arity() + "-ary relational value.");
    if (a2k.containsKey(f))
        return;
    a2k.put(f, expr);
}
 

/**
 * Add a new skolem to this solution and associate it with the given expression.
 * <br>
 * The expression must contain only constant Relations or Relations that are
 * already bound in this solution.
 */
private ExprVar addSkolem(String label, Type type, Expression expr) throws Err {
    if (solved)
        throw new ErrorFatal("Cannot add an additional skolem since solve() has completed.");
    int a = type.arity();
    if (a < 1)
        throw new ErrorFatal("Skolem " + label + " must be associated with a relational value.");
    if (a != expr.arity())
        throw new ErrorFatal("Skolem " + label + " must be associated with an " + a + "-ary relational value.");
    ExprVar v = ExprVar.make(Pos.UNKNOWN, label, type);
    a2k.put(v, expr);
    skolems.add(v);
    return v;
}
 

/**
 * Returns a formula stating that the given expression is acyclic.
 * @return {f: Formula | f <=> no ^expr & iden}
 * @throws IllegalArgumentException  expr.arity != 2
 */
public Formula acyclic(Expression expr) {
	if (expr instanceof Relation)
		return ((Relation)expr).acyclic();  // special handling for relations that enables better symmetry breaking
	
	if (expr.arity() != 2) throw new IllegalArgumentException();
	return expr.closure().intersection(Expression.IDEN).no();
}
 

/**
   * Returns a formula stating that the given relation is a total function
   * with the specified domain and range.
   * @return {f: Formula | f <=> expr in domain->range && all v: domain | one v.expr }
   * @throws NullPointerException  domain = null || range = null
   * @throws IllegalArgumentException  domain.arity != 1 || range.arity != 1
   * @throws IllegalArgumentException  this.arity != 2
   */
  public Formula function(Expression expr, Expression domain, Expression range) {
  	if (expr instanceof Relation)
  		return ((Relation)expr).function(domain, range);  // special handling for relations that enables better symmetry breaking
  	
  	if (domain.arity() != 1 || range.arity() != 1)
	throw new IllegalArgumentException("invalid arity: " + domain + " or " + range);
// expr in domain->range 
final Formula domainConstraint = expr.in(domain.product(range));
// all v: domain | one v.expr
final Variable v = Variable.unary("v"+expr.hashCode());
final Formula funConstraint = v.join(expr).one().forAll(v.oneOf(domain));
// expr in domain->range && all v: domain | targetMult v.relation
return domainConstraint.and(funConstraint);
  }