Java example source code file (NetworkTest.java)

This example Java source code file (NetworkTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

bytearrayinputstream, bytearrayoutputstream, classnotfoundexception, collection, featureinitializer, ioexception, network, networktest, neuron, neuronsquaremesh2d, nosuchelementexception, objectinputstream, objectoutputstream, test, util

The NetworkTest.java Java example source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.math3.ml.neuralnet;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Collection;
import java.util.NoSuchElementException;

import org.apache.commons.math3.ml.neuralnet.twod.NeuronSquareMesh2D;
import org.junit.Assert;
import org.junit.Test;

/**
 * Tests for {@link Network}.
 */
public class NetworkTest {
    final FeatureInitializer init = FeatureInitializerFactory.uniform(0, 2);

    @Test
    public void testGetFeaturesSize() {
        final FeatureInitializer[] initArray = { init, init, init };

        final Network net = new NeuronSquareMesh2D(2, false,
                                                   2, false,
                                                   SquareNeighbourhood.VON_NEUMANN,
                                                   initArray).getNetwork();
        Assert.assertEquals(3, net.getFeaturesSize());
    }

    /*
     * Test assumes that the network is
     *
     *  0-----1
     *  |     |
     *  |     |
     *  2-----3
     */
    @Test
    public void testDeleteLink() {
        final FeatureInitializer[] initArray = { init };
        final Network net = new NeuronSquareMesh2D(2, false,
                                                   2, false,
                                                   SquareNeighbourhood.VON_NEUMANN,
                                                   initArray).getNetwork();
        Collection<Neuron> neighbours;

        // Delete 0 --> 1.
        net.deleteLink(net.getNeuron(0),
                       net.getNeuron(1));

        // Link from 0 to 1 was deleted.
        neighbours = net.getNeighbours(net.getNeuron(0));
        Assert.assertFalse(neighbours.contains(net.getNeuron(1)));
        // Link from 1 to 0 still exists.
        neighbours = net.getNeighbours(net.getNeuron(1));
        Assert.assertTrue(neighbours.contains(net.getNeuron(0)));
    }

    /*
     * Test assumes that the network is
     *
     *  0-----1
     *  |     |
     *  |     |
     *  2-----3
     */
    @Test
    public void testDeleteNeuron() {
        final FeatureInitializer[] initArray = { init };
        final Network net = new NeuronSquareMesh2D(2, false,
                                                   2, false,
                                                   SquareNeighbourhood.VON_NEUMANN,
                                                   initArray).getNetwork();

        Assert.assertEquals(2, net.getNeighbours(net.getNeuron(0)).size());
        Assert.assertEquals(2, net.getNeighbours(net.getNeuron(3)).size());

        // Delete neuron 1.
        net.deleteNeuron(net.getNeuron(1));

        try {
            net.getNeuron(1);
        } catch (NoSuchElementException expected) {}

        Assert.assertEquals(1, net.getNeighbours(net.getNeuron(0)).size());
        Assert.assertEquals(1, net.getNeighbours(net.getNeuron(3)).size());
    }

    @Test
    public void testIterationOrder() {
        final FeatureInitializer[] initArray = { init };
        final Network net = new NeuronSquareMesh2D(4, false,
                                                   3, true,
                                                   SquareNeighbourhood.VON_NEUMANN,
                                                   initArray).getNetwork();

        // Check that the comparator provides a specific order.
        boolean isUnspecifiedOrder = false;
        long previousId = Long.MIN_VALUE;
        for (Neuron n : net.getNeurons(new Network.NeuronIdentifierComparator())) {
            final long currentId = n.getIdentifier();
            if (currentId < previousId) {
                isUnspecifiedOrder = true;
                break;
            }
            previousId = currentId;
        }
        Assert.assertFalse(isUnspecifiedOrder);
    }

    /*
     * Test assumes that the network is
     *
     *  0-----1
     *  |     |
     *  |     |
     *  2-----3
     */
    @Test
    public void testCopy() {
        final FeatureInitializer[] initArray = { init };
        final Network net = new NeuronSquareMesh2D(2, false,
                                                   2, false,
                                                   SquareNeighbourhood.VON_NEUMANN,
                                                   initArray).getNetwork();

        final Network copy = net.copy();

        final Neuron netNeuron0 = net.getNeuron(0);
        final Neuron copyNeuron0 = copy.getNeuron(0);
        final Neuron netNeuron1 = net.getNeuron(1);
        final Neuron copyNeuron1 = copy.getNeuron(1);
        Collection<Neuron> netNeighbours;
        Collection<Neuron> copyNeighbours;

        // Check that both networks have the same connections.
        netNeighbours = net.getNeighbours(netNeuron0);
        copyNeighbours = copy.getNeighbours(copyNeuron0);
        Assert.assertTrue(netNeighbours.contains(netNeuron1));
        Assert.assertTrue(copyNeighbours.contains(copyNeuron1));

        // Delete neuron 1 from original.
        net.deleteNeuron(netNeuron1);

        // Check that the networks now differ.
        netNeighbours = net.getNeighbours(netNeuron0);
        copyNeighbours = copy.getNeighbours(copyNeuron0);
        Assert.assertFalse(netNeighbours.contains(netNeuron1));
        Assert.assertTrue(copyNeighbours.contains(copyNeuron1));
    }

    @Test
    public void testSerialize()
        throws IOException,
               ClassNotFoundException {
        final FeatureInitializer[] initArray = { init };
        final Network out = new NeuronSquareMesh2D(4, false,
                                                   3, true,
                                                   SquareNeighbourhood.VON_NEUMANN,
                                                   initArray).getNetwork();

        final ByteArrayOutputStream bos = new ByteArrayOutputStream();
        final ObjectOutputStream oos = new ObjectOutputStream(bos);
        oos.writeObject(out);

        final ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
        final ObjectInputStream ois = new ObjectInputStream(bis);
        final Network in = (Network) ois.readObject();

        for (Neuron nOut : out) {
            final Neuron nIn = in.getNeuron(nOut.getIdentifier());

            // Same values.
            final double[] outF = nOut.getFeatures();
            final double[] inF = nIn.getFeatures();
            Assert.assertEquals(outF.length, inF.length);
            for (int i = 0; i < outF.length; i++) {
                Assert.assertEquals(outF[i], inF[i], 0d);
            }

            // Same neighbours.
            final Collection<Neuron> outNeighbours = out.getNeighbours(nOut);
            final Collection<Neuron> inNeighbours = in.getNeighbours(nIn);
            Assert.assertEquals(outNeighbours.size(), inNeighbours.size());
            for (Neuron oN : outNeighbours) {
                Assert.assertTrue(inNeighbours.contains(in.getNeuron(oN.getIdentifier())));
            }
        }
    }
}