01 /*
02 * Java Genetic Algorithm Library (jenetics-3.7.0).
03 * Copyright (c) 2007-2016 Franz Wilhelmstötter
04 *
05 * Licensed under the Apache License, Version 2.0 (the "License");
06 * you may not use this file except in compliance with the License.
07 * You may obtain a copy of the License at
08 *
09 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 * Author:
18 * Franz Wilhelmstötter (franz.wilhelmstoetter@gmx.at)
19 */
20 package org.jenetics.tool.problem;
21
22 import java.awt.Point;
23 import java.util.stream.IntStream;
24
25 import org.jenetics.EnumGene;
26 import org.jenetics.Optimize;
27 import org.jenetics.engine.Codec;
28 import org.jenetics.engine.Engine;
29 import org.jenetics.engine.EvolutionResult;
30 import org.jenetics.engine.codecs;
31 import org.jenetics.util.ISeq;
32
33 /**
34 * @author <a href="mailto:franz.wilhelmstoetter@gmx.at">Franz Wilhelmstötter</a>
35 * @version 3.6
36 * @since 3.6
37 */
38 public class TSM {
39 // The locations to visit.
40 static final ISeq<Point> POINTS = ISeq.of(
41 new Point(0, 0), new Point(1, 2), new Point(4, 5) // ...
42 );
43
44 // The permutation codec.
45 static final Codec<ISeq<Point>, EnumGene<Point>> CODEC =
46 codecs.ofPermutation(POINTS);
47
48 // The fitness function (in the problem domain).
49 static double dist(final ISeq<Point> p) {
50 return IntStream.range(0, p.length())
51 .mapToDouble(i -> p.get(i).distance(p.get(i + i%p.length())))
52 .sum();
53 }
54
55 // The evolution engine.
56 static final Engine<EnumGene<Point>, Double> ENGINE = Engine
57 .builder(TSM::dist, CODEC)
58 .optimize(Optimize.MINIMUM)
59 .build();
60
61 // Find the solution.
62 public static void main(final String[] args) {
63 final ISeq<Point> result = ENGINE.stream()
64 .limit(10)
65 .collect(EvolutionResult.toBestResult(CODEC));
66
67 System.out.println(result);
68 }
69 }
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