/*******************************************************************************
 * Copyright (c) 2010 Haifeng Li
 *   
 * Licensed 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 smile.gap;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import static org.junit.Assert.*;

/**
 *
 * @author Haifeng Li
 */
public class GeneticAlgorithmTest {
    
    public GeneticAlgorithmTest() {
    }

    @BeforeClass
    public static void setUpClass() throws Exception {
    }

    @AfterClass
    public static void tearDownClass() throws Exception {
    }
    
    @Before
    public void setUp() {
    }
    
    @After
    public void tearDown() {
    }

    class Knapnack implements FitnessMeasure {

        int limit = 9; // weight limit
        int[] weight = {2, 3, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
        double[] reward = {6, 6, 6, 5, 1.3, 1.2, 1.1, 1.0, 1.1, 1.3, 1.0, 1.0, 0.9, 0.8, 0.6};

        @Override
        public double fit(BitString chromosome) {
            double wsum = 0.0;
            double rew = 0.0;
            int[] bits = chromosome.bits();
            for (int i = 0; i < weight.length; i++) {
                if (bits[i] == 1) {
                    wsum += weight[i];
                    rew += reward[i];
                }
            }
            
            // subtract penalty for exceeding weight
            if (wsum > limit) {
                rew -= 5 * (wsum - limit);
            }

            return rew;
        }
    }

    /**
     * Test of evolve method, of class GeneticAlgorithm.
     */
    @Test
    public void testEvolve() {
        System.out.println("evolve");
        BitString[] seeds = new BitString[100];
        
        // The mutation parameters are set higher than usual to prevent premature convergence. 
        for (int i = 0; i < seeds.length; i++) {
            seeds[i] = new BitString(15, new Knapnack(), BitString.Crossover.UNIFORM, 1.0, 0.2);
        }
        
        GeneticAlgorithm instance = new GeneticAlgorithm<>(seeds, GeneticAlgorithm.Selection.TOURNAMENT);
        instance.setElitism(2);
        instance.setTournament(3, 0.95);
        
        BitString result = instance.evolve(1000, 18);
        assertEquals(18, result.fitness(), 1E-7);

        int[] best = {1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
        for (int i = 0; i < best.length; i++) {
            assertEquals(best[i], result.bits()[i]);
        }
        
    }
}