01 /*
02 * Java Genetic Algorithm Library (jenetics-6.3.0).
03 * Copyright (c) 2007-2021 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@gmail.com)
19 */
20 package io.jenetics.ext;
21
22 import io.jenetics.Gene;
23 import io.jenetics.engine.Engine.Builder;
24 import io.jenetics.engine.Engine.Setup;
25 import io.jenetics.internal.util.Requires;
26
27 /**
28 * Configures the evolution engine to execute the
29 * <a href="https://en.wikipedia.org/wiki/Weasel_program">Weasel program</a>
30 * algorithm.
31 *
32 * <pre>{@code
33 * final Engine<CharacterGene, Integer> engine = Engine.builder(problem)
34 * .setup(new WeaselProgram<>())
35 * .build();
36 * }</pre>
37 *
38 * @see WeaselSelector
39 * @see WeaselMutator
40 * @see io.jenetics.engine.Engine.Builder#setup(Setup)
41 *
42 * @param <G> the gene type
43 * @param <C> the fitness result type
44 *
45 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
46 * @version 6.0
47 * @since 6.0
48 */
49 public final class WeaselProgram<
50 G extends Gene<?, G>,
51 C extends Comparable<? super C>
52 >
53 implements Setup<G, C>
54 {
55
56 private final double _mutationProbability;
57
58 /**
59 * Create a new weasel program setup with the give mutation probability.
60 *
61 * @param mutationProbability the mutation probability
62 * @throws IllegalArgumentException if the {@code mutationProbability} is
63 * not in the valid range of {@code [0, 1]}.
64 */
65 public WeaselProgram(final double mutationProbability) {
66 _mutationProbability = Requires.probability(mutationProbability);
67 }
68
69 /**
70 * Create a new weasel program setup with the <em>default</em> mutation
71 * probability of {@code 0.05}.
72 */
73 public WeaselProgram() {
74 this(0.05);
75 }
76
77 @Override
78 public void apply(final Builder<G, C> builder) {
79 builder
80 .selector(new WeaselSelector<>())
81 .offspringFraction(1)
82 .alterers(new WeaselMutator<>(_mutationProbability));
83 }
84
85 }
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