com.salesforce.jgrapht.generate.HyperCubeGraphGenerator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of AptSpringProcessor Show documentation

This project contains the apt processor that implements all the checks enumerated in @Verify. It is a self contained, and shaded jar.

There is a newer version: 2.0.7

Show newest version

/*
 * (C) Copyright 2008-2017, by Andrew Newell and Contributors.
 *
 * JGraphT : a free Java graph-theory library
 *
 * This program and the accompanying materials are dual-licensed under
 * either
 *
 * (a) the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation, or (at your option) any
 * later version.
 *
 * or (per the licensee's choosing)
 *
 * (b) the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation.
 */
package com.salesforce.jgrapht.generate;

import java.util.*;

import com.salesforce.jgrapht.*;

/**
 * Generates a hyper cube graph of
 * any size. This is a graph that can be represented by bit strings, so for an n-dimensial hypercube
 * each vertex resembles an n-length bit string. Then, two vertices are adjacent if and only if
 * their bitstring differ by exactly one element.
 * 
 * @param  the graph vertex type
 * @param  the graph edge type
 *
 * @author Andrew Newell
 * @since Dec 21, 2008
 */
public class HyperCubeGraphGenerator
    implements GraphGenerator
{
    private int dim;

    /**
     * Creates a new HyperCubeGraphGenerator object.
     *
     * @param dim This is the dimension of the hypercube.
     */
    public HyperCubeGraphGenerator(int dim)
    {
        this.dim = dim;
    }

    /**
     * This will generate the hypercube graph
     */
    @Override
    public void generateGraph(
        Graph target, final VertexFactory vertexFactory, Map resultMap)
    {
        // Vertices are created, and they are included in the resultmap as their
        // bitstring representation
        int order = (int) Math.pow(2, dim);
        LinkedList vertices = new LinkedList<>();
        for (int i = 0; i < order; i++) {
            V newVertex = vertexFactory.createVertex();
            target.addVertex(newVertex);
            vertices.add(newVertex);
            if (resultMap != null) {
                String s = Integer.toBinaryString(i);
                while (s.length() < dim) {
                    s = "0" + s;
                }
                resultMap.put(s, newVertex);
            }
        }

        // Two vertices will have an edge if their bitstrings differ by exactly
        // 1 element
        for (int i = 0; i < order; i++) {
            for (int j = i + 1; j < order; j++) {
                for (int z = 0; z < dim; z++) {
                    if ((j ^ i) == (1 << z)) {
                        target.addEdge(vertices.get(i), vertices.get(j));
                        break;
                    }
                }
            }
        }
    }
}

// End HyberCubeGraphGenerator.java