001 /*
002 * Java Genetic Algorithm Library (jenetics-4.0.0).
003 * Copyright (c) 2007-2017 Franz Wilhelmstötter
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 *
017 * Author:
018 * Franz Wilhelmstötter (franz.wilhelmstoetter@gmail.com)
019 */
020 package io.jenetics;
021
022 import static java.lang.String.format;
023 import static io.jenetics.util.RandomRegistry.getRandom;
024
025 import java.io.Serializable;
026 import java.util.Random;
027
028 import io.jenetics.internal.math.random;
029 import io.jenetics.util.ISeq;
030 import io.jenetics.util.IntRange;
031 import io.jenetics.util.MSeq;
032 import io.jenetics.util.Mean;
033
034 /**
035 * NumericGene implementation which holds a 32 bit integer number.
036 *
037 * <p>This is a <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/doc-files/ValueBased.html">
038 * value-based</a> class; use of identity-sensitive operations (including
039 * reference equality ({@code ==}), identity hash code, or synchronization) on
040 * instances of {@code IntegerGene} may have unpredictable results and should
041 * be avoided.
042 *
043 * @see IntegerChromosome
044 *
045 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
046 * @since 2.0
047 * @version 4.0
048 */
049 public final class IntegerGene
050 extends AbstractNumericGene<Integer, IntegerGene>
051 implements
052 NumericGene<Integer, IntegerGene>,
053 Mean<IntegerGene>,
054 Comparable<IntegerGene>,
055 Serializable
056 {
057
058 private static final long serialVersionUID = 1L;
059
060 /**
061 * Create a new random {@code IntegerGene} with the given value and the
062 * given range. If the {@code value} isn't within the interval [min, max],
063 * no exception is thrown. In this case the method
064 * {@link IntegerGene#isValid()} returns {@code false}.
065 *
066 * @param value the value of the gene.
067 * @param min the minimal valid value of this gene (inclusively).
068 * @param max the maximal valid value of this gene (inclusively).
069 * @throws NullPointerException if one of the arguments is {@code null}.
070 */
071 IntegerGene(final Integer value, final Integer min, final Integer max) {
072 super(value, min, max);
073 }
074
075 @Override
076 public int compareTo(final IntegerGene other) {
077 return _value.compareTo(other._value);
078 }
079
080 /**
081 * Create a new random {@code IntegerGene} with the given value and the
082 * given range. If the {@code value} isn't within the interval [min, max],
083 * no exception is thrown. In this case the method
084 * {@link IntegerGene#isValid()} returns {@code false}.
085 *
086 * @param value the value of the gene.
087 * @param min the minimal valid value of this gene (inclusively).
088 * @param max the maximal valid value of this gene (inclusively).
089 * @return a new {@code IntegerGene} with the given {@code value}
090 */
091 public static IntegerGene of(final int value, final int min, final int max) {
092 return new IntegerGene(value, min, max);
093 }
094
095 /**
096 * Create a new random {@code IntegerGene} with the given value and the
097 * given range. If the {@code value} isn't within the interval [min, max],
098 * no exception is thrown. In this case the method
099 * {@link IntegerGene#isValid()} returns {@code false}.
100 *
101 * @since 3.2
102 *
103 * @param value the value of the gene.
104 * @param range the integer range to use
105 * @return a new {@code IntegerGene} with the give {@code value}
106 * @throws NullPointerException if the given {@code range} is {@code null}.
107 */
108 public static IntegerGene of(final int value, final IntRange range) {
109 return new IntegerGene(value, range.getMin(), range.getMax());
110 }
111
112 /**
113 * Create a new random {@code IntegerGene}. It is guaranteed that the value of
114 * the {@code IntegerGene} lies in the interval [min, max].
115 *
116 * @param min the minimal valid value of this gene (inclusively).
117 * @param max the maximal valid value of this gene (inclusively).
118 * @return a new random {@code IntegerGene}
119 */
120 public static IntegerGene of(final int min, final int max) {
121 return of(nextInt(getRandom(), min, max), min, max);
122 }
123
124 /**
125 * Create a new random {@code IntegerGene}. It is guaranteed that the value of
126 * the {@code IntegerGene} lies in the interval [min, max].
127 *
128 * @since 3.2
129 *
130 * @param range the integer range to use
131 * @return a new random {@code IntegerGene}
132 * @throws NullPointerException if the given {@code range} is {@code null}.
133 */
134 public static IntegerGene of(final IntRange range) {
135 return of(nextInt(getRandom(), range.getMin(), range.getMax()), range);
136 }
137
138 static ISeq<IntegerGene> seq(
139 final Integer minimum,
140 final Integer maximum,
141 final IntRange lengthRange
142 ) {
143 final int min = minimum;
144 final int max = maximum;
145 final Random r = getRandom();
146
147 return MSeq.<IntegerGene>ofLength(random.nextInt(lengthRange, r))
148 .fill(() -> new IntegerGene(nextInt(r, min, max), minimum, maximum))
149 .toISeq();
150 }
151
152 @Override
153 public IntegerGene newInstance(final Number number) {
154 return new IntegerGene(number.intValue(), _min, _max);
155 }
156
157 @Override
158 public IntegerGene newInstance() {
159 return new IntegerGene(
160 nextInt(getRandom(), _min, _max), _min, _max
161 );
162 }
163
164 @Override
165 public IntegerGene mean(final IntegerGene that) {
166 return new IntegerGene(_value + (that._value - _value)/2, _min, _max);
167 }
168
169 /**
170 * Returns a pseudo-random, uniformly distributed int value between min and
171 * max (min and max included).
172 *
173 * @param random the random engine to use for calculating the random int
174 * value
175 * @param min lower bound for generated integer
176 * @param max upper bound for generated integer
177 * @return a random integer greater than or equal to {@code min} and
178 * less than or equal to {@code max}
179 * @throws IllegalArgumentException if {@code min > max}
180 * @throws NullPointerException if the given {@code random}
181 * engine is {@code null}.
182 */
183 static int nextInt(
184 final Random random,
185 final int min, final int max
186 ) {
187 if (min > max) {
188 throw new IllegalArgumentException(format(
189 "Min >= max: %d >= %d", min, max
190 ));
191 }
192
193 final int diff = max - min + 1;
194 int result = 0;
195
196 if (diff <= 0) {
197 do {
198 result = random.nextInt();
199 } while (result < min || result > max);
200 } else {
201 result = random.nextInt(diff) + min;
202 }
203
204 return result;
205 }
206
207 }
|