fr.lirmm.graphik.integraal.rulesetanalyser.graph.JointlyAffectedPositionSet Maven / Gradle / Ivy

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Rule base analysis for InteGraal. This is imported from Graal
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/*
 * Copyright (C) Inria Sophia Antipolis - Méditerranée / LIRMM
 * (Université de Montpellier & CNRS) (2014 - 2017)
 *
 * Contributors :
 *
 * Clément SIPIETER 
 * Mélanie KÖNIG
 * Swan ROCHER
 * Jean-François BAGET
 * Michel LECLÈRE
 * Marie-Laure MUGNIER 
 *
 *
 * This file is part of Graal .
 *
 * This software is governed by the CeCILL  license under French law and
 * abiding by the rules of distribution of free software.  You can  use,
 * modify and/ or redistribute the software under the terms of the CeCILL
 * license as circulated by CEA, CNRS and INRIA at the following URL
 * "http://www.cecill.info".
 *
 * As a counterpart to the access to the source code and  rights to copy,
 * modify and redistribute granted by the license, users are provided only
 * with a limited warranty  and the software's author,  the holder of the
 * economic rights,  and the successive licensors  have only  limited
 * liability.
 *
 * In this respect, the user's attention is drawn to the risks associated
 * with loading,  using,  modifying and/or developing or reproducing the
 * software by the user in light of its specific status of free software,
 * that may mean  that it is complicated to manipulate,  and  that  also
 * therefore means  that it is reserved for developers  and  experienced
 * professionals having in-depth computer knowledge. Users are therefore
 * encouraged to load and test the software's suitability as regards their
 * requirements in conditions enabling the security of their systems and/or
 * data to be ensured and,  more generally, to use and operate it in the
 * same conditions as regards security.
 *
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL license and that you accept its terms.
 */
 /**
 * 
 */
package fr.lirmm.graphik.integraal.rulesetanalyser.graph;

import java.util.Iterator;

import fr.lirmm.graphik.integraal.api.core.Atom;
import fr.lirmm.graphik.integraal.api.core.InMemoryAtomSet;
import fr.lirmm.graphik.integraal.api.core.Rule;
import fr.lirmm.graphik.integraal.api.core.Term;
import fr.lirmm.graphik.integraal.api.core.Variable;
import fr.lirmm.graphik.util.stream.CloseableIteratorWithoutException;

/**
 * The affected position set is built from a rule set by the following
 * procedure: (i) for each rule and for each existentially quantified variable
 * occuring at position p[i] in its head, p[i] is affected; (ii) for each rule
 * and for each variable x that occurs only at affected positions in its body,
 * all positions q[j] in its head where occurs x are affected.
 * 
 * A variable is said to be affected if it occurs only at affected positions.
 * 
 * @author Clément Sipieter (INRIA) {@literal }
 * @author Swan Rocher
 * 
 */
public class JointlyAffectedPositionSet extends AbstractAffectedPositionSet {


	public JointlyAffectedPositionSet(Iterable ruleSet) {
		super(ruleSet);
	}
	

	/**
	 * for each rule and for each variable x that occurs only at affected
	 * positions in its body, all positions q[j] in its head where occurs x are
	 * affected.
	 */
	protected void step2() {
		InMemoryAtomSet body;
		boolean isAffected;
		int i;
		CloseableIteratorWithoutException atomIt;
		Iterator termIt;
		Atom a;
		Term t;
		boolean fixPoint = false;

		while (!fixPoint) {
			fixPoint = true;
			for (Rule rule : ruleSet) {
				body = rule.getBody();
				for (Variable term : rule.getBody().getVariables()) {
					isAffected = true;
					atomIt = body.iterator();
					while (atomIt.hasNext() && isAffected) {
						i = -1;
						a = atomIt.next();
						termIt = a.iterator();
						while (termIt.hasNext() && isAffected) {
							++i;
							t = termIt.next();
							if (term.equals(t)) {
								if (!isAffected(a.getPredicate(), i)) {
									isAffected = false;
								}
							}
						}
					}
					if (isAffected) {
						if (this.affectInHead(rule, term)) {
							fixPoint = false;
						}
					}
				}
			}
		}
	}
};