Java tutorial
/* * This file is part of JGAP. * * JGAP offers a dual license model containing the LGPL as well as the MPL. * * For licensing information please see the file license.txt included with JGAP * or have a look at the top of class org.jgap.Chromosome which representatively * includes the JGAP license policy applicable for any file delivered with JGAP. */ package examples; import java.io.*; import java.awt.image.*; import org.jfree.chart.*; import org.jfree.chart.plot.*; import org.jfree.data.category.*; import org.jgap.*; import org.jgap.impl.*; /** * Copy of class MinimizingMakeChange with added support for JFreeChart, see * code below. In the given directory, a file named "chart.jpg" will be created. * * This implementation was tested with JFreeChart 1.0.11, but newer versions * should do as well. * * @author Neil Rotstan * @author Klaus Meffert * @since 1.0 */ public class MinimizingMakeChangeWithChart { /** * The total number of times we'll let the population evolve. */ private static final int MAX_ALLOWED_EVOLUTIONS = 200; /** * Executes the genetic algorithm to determine the minimum number of * coins necessary to make up the given target amount of change. The * solution will then be written to System.out. * * @param a_targetChangeAmount the target amount of change for which this * method is attempting to produce the minimum number of coins * @param a_chartDirectory directory to put the chart in * * @throws Exception * * @author Neil Rotstan * @author Klaus Meffert * @since 1.0 */ public static void makeChangeForAmount(int a_targetChangeAmount, String a_chartDirectory) throws Exception { // Start with a DefaultConfiguration, which comes setup with the // most common settings. // ------------------------------------------------------------- Configuration conf = new DefaultConfiguration(); conf.setPreservFittestIndividual(true); conf.setKeepPopulationSizeConstant(false); // Set the fitness function we want to use, which is our // MinimizingMakeChangeFitnessFunction. We construct it with // the target amount of change passed in to this method. // --------------------------------------------------------- FitnessFunction myFunc = new MinimizingMakeChangeFitnessFunction(a_targetChangeAmount); // conf.setFitnessFunction(myFunc); conf.setBulkFitnessFunction(new BulkFitnessOffsetRemover(myFunc)); // Optionally, this example is working with DeltaFitnessEvaluator. // See MinimizingMakeChangeFitnessFunction for details! // --------------------------------------------------------------- // conf.setFitnessEvaluator(new DeltaFitnessEvaluator()); // Now we need to tell the Configuration object how we want our // Chromosomes to be setup. We do that by actually creating a // sample Chromosome and then setting it on the Configuration // object. As mentioned earlier, we want our Chromosomes to each // have four genes, one for each of the coin types. We want the // values (alleles) of those genes to be integers, which represent // how many coins of that type we have. We therefore use the // IntegerGene class to represent each of the genes. That class // also lets us specify a lower and upper bound, which we set // to sensible values for each coin type. // -------------------------------------------------------------- Gene[] sampleGenes = new Gene[4]; sampleGenes[0] = new IntegerGene(conf, 0, 3 * 10); // Quarters sampleGenes[1] = new IntegerGene(conf, 0, 2 * 10); // Dimes sampleGenes[2] = new IntegerGene(conf, 0, 1 * 10); // Nickels sampleGenes[3] = new IntegerGene(conf, 0, 4 * 10); // Pennies IChromosome sampleChromosome = new Chromosome(conf, sampleGenes); conf.setSampleChromosome(sampleChromosome); // Finally, we need to tell the Configuration object how many // Chromosomes we want in our population. The more Chromosomes, // the larger number of potential solutions (which is good for // finding the answer), but the longer it will take to evolve // the population (which could be seen as bad). // ------------------------------------------------------------ conf.setPopulationSize(80); // JFreeChart: setup DefaultCategoryDataset dataset = new DefaultCategoryDataset(); PlotOrientation or = PlotOrientation.VERTICAL; // Create random initial population of Chromosomes. // ------------------------------------------------ Genotype population = Genotype.randomInitialGenotype(conf); // Evolve the population. Since we don't know what the best answer // is going to be, we just evolve the max number of times. // --------------------------------------------------------------- for (int i = 0; i < MAX_ALLOWED_EVOLUTIONS; i++) { population.evolve(); // JFreeChart: add current best fitness to chart double fitness = population.getFittestChromosome().getFitnessValue(); if (i % 3 == 0) { String s = String.valueOf(i); dataset.setValue(fitness, "Fitness", s); } } // Display the best solution we found. // ----------------------------------- IChromosome bestSolutionSoFar = population.getFittestChromosome(); System.out.println("The best solution has a fitness value of " + bestSolutionSoFar.getFitnessValue()); System.out.println("It contained the following: "); System.out.println("\t" + MinimizingMakeChangeFitnessFunction.getNumberOfCoinsAtGene(bestSolutionSoFar, 0) + " quarters."); System.out.println("\t" + MinimizingMakeChangeFitnessFunction.getNumberOfCoinsAtGene(bestSolutionSoFar, 1) + " dimes."); System.out.println("\t" + MinimizingMakeChangeFitnessFunction.getNumberOfCoinsAtGene(bestSolutionSoFar, 2) + " nickels."); System.out.println("\t" + MinimizingMakeChangeFitnessFunction.getNumberOfCoinsAtGene(bestSolutionSoFar, 3) + " pennies."); System.out.println("For a total of " + MinimizingMakeChangeFitnessFunction.amountOfChange(bestSolutionSoFar) + " cents in " + MinimizingMakeChangeFitnessFunction.getTotalNumberOfCoins(bestSolutionSoFar) + " coins."); // JFreeChart: Create chart JFreeChart chart = ChartFactory.createLineChart("JGAP: Evolution progress", "Evolution cycle", "Fitness value", dataset, or, true /*legend*/, true /*tooltips*/ , false /*urls*/); BufferedImage image = chart.createBufferedImage(640, 480); String imagefile = "chart.jpg"; FileOutputStream fo = new FileOutputStream(a_chartDirectory + imagefile); ChartUtilities.writeBufferedImageAsJPEG(fo, 0.7f, image); System.out.println("Chart written to image file " + a_chartDirectory + imagefile); } /** * Main method. A single command-line argument is expected, which is the * amount of change to create (in other words, 75 would be equal to 75 * cents). * * @param args amount of change in cents to create * @throws Exception * * @author Neil Rotstan * @author Klaus Meffert * @since 1.0 */ public static void main(String[] args) throws Exception { if (args.length != 2) { System.out.println("Syntax: MinimizingMakeChange <amount> <directory for outputting chart>"); } else { int amount = 0; try { amount = Integer.parseInt(args[0]); } catch (NumberFormatException e) { System.out.println("The <amount> argument must be a valid integer value"); System.exit(1); } if (amount < 1 || amount >= MinimizingMakeChangeFitnessFunction.MAX_BOUND) { System.out.println("The <amount> argument must be between 1 and " + (MinimizingMakeChangeFitnessFunction.MAX_BOUND - 1) + "."); } else { String dir = args[1]; if (!dir.endsWith("\\") && !dir.endsWith("/")) { dir += "\\"; } makeChangeForAmount(amount, dir); } } } }