fr.lirmm.graphik.util.MathUtils.java Source code

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Here is the source code for fr.lirmm.graphik.util.MathUtils.java

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/*
 * Copyright (C) Inria Sophia Antipolis - Mditerrane / LIRMM
 * (Universit de Montpellier & CNRS) (2014 - 2015)
 *
 * Contributors :
 *
 * Clment SIPIETER <clement.sipieter@inria.fr>
 * Mlanie KNIG
 * Swan ROCHER
 * Jean-Franois BAGET
 * Michel LECLRE
 * Marie-Laure MUGNIER <mugnier@lirmm.fr>
 *
 *
 * This file is part of Graal <https://graphik-team.github.io/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.util;

import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;

import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.commons.lang3.tuple.Pair;

/**
 * @author Clment Sipieter (INRIA) {@literal <clement@6pi.fr>}
 *
 */
public final class MathUtils {

    // /////////////////////////////////////////////////////////////////////////
    // CONSTRUCTORS
    // /////////////////////////////////////////////////////////////////////////

    private MathUtils() {
    }

    // /////////////////////////////////////////////////////////////////////////
    // PUBLIC METHODS
    // /////////////////////////////////////////////////////////////////////////

    /**
     * Comput the cartesian product of the specified set with itself.
     * input: { A, B, C }
     * output : { (A,A), (A,B), (B,B) } 
     * @param set
     * @return
     */
    public static <T> Iterable<Pair<T, T>> selfCartesianProduct(Iterable<T> set) {
        Collection<Pair<T, T>> pairs = new LinkedList<Pair<T, T>>();

        Iterator<T> it = set.iterator();
        while (it.hasNext()) {
            T a = it.next();
            for (T b : set) {
                pairs.add(new ImmutablePair<T, T>(a, b));
            }

            if (it.hasNext()) { // FIXfor singleton implementation
                it.remove();
            }
        }
        return pairs;
    }

    // /////////////////////////////////////////////////////////////////////////
    // OBJECT OVERRIDE METHODS
    // /////////////////////////////////////////////////////////////////////////

    // /////////////////////////////////////////////////////////////////////////
    // PRIVATE METHODS
    // /////////////////////////////////////////////////////////////////////////

}