| /* |
| * 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.knapsack; |
| |
| 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 simply want to |
| * calculate the weight and value of an individual solution relative to other solutions.</p> |
| * <p> |
| * To do this, we total the weights and values of all the genes within a chromosome.</p> |
| */ |
| public class KnapsackFitnessFunction implements IFitnessFunction { |
| /** |
| * {@inheritDoc} |
| */ |
| @Override public double evaluate(List<Gene> genes) { |
| double val = 0; |
| double weight = 0; |
| |
| List<Long> duplicates = new ArrayList<>(); |
| int badSolution = 1; |
| |
| for (Gene gene : genes) { |
| weight += ((Item)(gene.getVal())).getWeight(); |
| val += ((Item)(gene.getVal())).getVal(); |
| |
| double maximumWeight = 20; |
| if (duplicates.contains(gene.id()) || (weight > maximumWeight)) { |
| badSolution = 0; |
| break; |
| } |
| else |
| duplicates.add(gene.id()); |
| } |
| |
| return (val * badSolution); |
| } |
| } |