| /* |
| * 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.ignite.examples.ml.genetic.movie; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import org.apache.ignite.ml.genetic.Gene; |
| import org.apache.ignite.ml.genetic.IFitnessFunction; |
| |
| /** |
| * This example demonstrates how to create a {@link IFitnessFunction}. |
| * <p> |
| * Your fitness function will vary depending on your particular use case. For this fitness function, we want to |
| * calculate the value of an individual solution relative to other solutions.</p> |
| * <p> |
| * To do this, we increase fitness score by number of times genre is found in list of movies. In addition, we increase |
| * score by fictional IMDB rating.</p> |
| * <p> |
| * If there are duplicate movies in selection, we automatically apply a '0' fitness score.</p> |
| */ |
| public class MovieFitnessFunction implements IFitnessFunction { |
| /** |
| * Genres. |
| */ |
| private List<String> genres; |
| |
| /** |
| * Create instance. |
| * |
| * @param genres List of genres. |
| */ |
| public MovieFitnessFunction(List<String> genres) { |
| this.genres = genres; |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override public double evaluate(List<Gene> genes) { |
| double score = 0; |
| List<String> duplicates = new ArrayList<>(); |
| int badSolution = 1; |
| |
| for (Gene gene : genes) { |
| Movie movie = (Movie)gene.getVal(); |
| if (duplicates.contains(movie.getName())) |
| badSolution = 0; |
| else |
| duplicates.add(movie.getName()); |
| |
| double genreScore = getGenreScore(movie); |
| if (genreScore == 0) |
| badSolution = 0; |
| |
| score = (score + movie.getImdbRating()) + (genreScore); |
| } |
| return (score * badSolution); |
| } |
| |
| /** |
| * Helper to calculate genre score. |
| * |
| * @param movie Movie. |
| * @return Genre score. |
| */ |
| private double getGenreScore(Movie movie) { |
| double genreScore = 0; |
| |
| for (String genre : genres) { |
| if (movie.getGenre().contains(genre)) |
| genreScore += 1; |
| } |
| return genreScore; |
| } |
| } |