001 /*
002 * Java Genetic Algorithm Library (jenetics-4.3.0).
003 * Copyright (c) 2007-2018 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.internal.util.Hashes.hash;
024 import static io.jenetics.util.RandomRegistry.getRandom;
025
026 import java.io.Serializable;
027 import java.util.Random;
028
029 import io.jenetics.internal.math.random;
030 import io.jenetics.util.ISeq;
031 import io.jenetics.util.IntRange;
032 import io.jenetics.util.LongRange;
033 import io.jenetics.util.MSeq;
034 import io.jenetics.util.Mean;
035
036 /**
037 * NumericGene implementation which holds a 64 bit integer number.
038 *
039 * <p>This is a <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/doc-files/ValueBased.html">
040 * value-based</a> class; use of identity-sensitive operations (including
041 * reference equality ({@code ==}), identity hash code, or synchronization) on
042 * instances of {@code LongGene} may have unpredictable results and should
043 * be avoided.
044 *
045 * @see LongChromosome
046 *
047 * @implNote
048 * This class is immutable and thread-safe.
049 *
050 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
051 * @since 1.6
052 * @version 4.3
053 */
054 public final class LongGene
055 implements
056 NumericGene<Long, LongGene>,
057 Mean<LongGene>,
058 Comparable<LongGene>,
059 Serializable
060 {
061
062 private static final long serialVersionUID = 2L;
063
064 private final long _value;
065 private final long _min;
066 private final long _max;
067
068 /**
069 * Create a new random {@code LongGene} with the given value and the
070 * given range. If the {@code value} isn't within the interval [min, max],
071 * no exception is thrown. In this case the method
072 * {@link LongGene#isValid()} returns {@code false}.
073 *
074 * @param value the value of the gene.
075 * @param min the minimal valid value of this gene (inclusively).
076 * @param max the maximal valid value of this gene (inclusively).
077 */
078 private LongGene(final long value, final long min, final long max) {
079 _value = value;
080 _min = min;
081 _max = max;
082 }
083
084 @Override
085 public Long getAllele() {
086 return _value;
087 }
088
089 @Override
090 public Long getMin() {
091 return _min;
092 }
093
094 @Override
095 public Long getMax() {
096 return _max;
097 }
098
099 @Override
100 public byte byteValue() {
101 return (byte)_value;
102 }
103
104 @Override
105 public short shortValue() {
106 return (short)_value;
107 }
108
109 @Override
110 public int intValue() {
111 return (int)_value;
112 }
113
114 @Override
115 public long longValue() {
116 return _value;
117 }
118
119 @Override
120 public float floatValue() {
121 return (float)_value;
122 }
123
124 @Override
125 public double doubleValue() {
126 return _value;
127 }
128
129 @Override
130 public boolean isValid() {
131 return _value >= _min && _value <= _max;
132 }
133
134 @Override
135 public int compareTo(final LongGene other) {
136 return Long.compare(_value, other._value);
137 }
138
139 @Override
140 public LongGene newInstance(final Long number) {
141 return LongGene.of(number, _min, _max);
142 }
143
144 @Override
145 public LongGene newInstance(final Number number) {
146 return LongGene.of(number.longValue(), _min, _max);
147 }
148
149 @Override
150 public LongGene newInstance() {
151 return LongGene.of(nextLong(getRandom(), _min, _max), _min, _max);
152 }
153
154 @Override
155 public LongGene mean(final LongGene that) {
156 return LongGene.of(_value + (that._value - _value)/2, _min, _max);
157 }
158
159 @Override
160 public int hashCode() {
161 return hash(_value, hash(_min, hash(_max, hash(getClass()))));
162 }
163
164 @Override
165 public boolean equals(final Object obj) {
166 return obj == this ||
167 obj instanceof LongGene &&
168 ((LongGene)obj)._value == _value &&
169 ((LongGene)obj)._min == _min &&
170 ((LongGene)obj)._max == _max;
171 }
172
173 @Override
174 public String toString() {
175 return String.format("[%s]", _value);
176 }
177
178 /* *************************************************************************
179 * Static factory methods.
180 * ************************************************************************/
181
182 /**
183 * Create a new random {@code LongGene} with the given value and the
184 * given range. If the {@code value} isn't within the interval [min, max],
185 * no exception is thrown. In this case the method
186 * {@link LongGene#isValid()} returns {@code false}.
187 *
188 * @param value the value of the gene.
189 * @param min the minimal valid value of this gene (inclusively).
190 * @param max the maximal valid value of this gene (inclusively).
191 * @return a new {@code LongGene} with the given parameters.
192 */
193 public static LongGene of(final long value, final long min, final long max) {
194 return new LongGene(value, min, max);
195 }
196
197 /**
198 * Create a new random {@code LongGene} with the given value and the
199 * given range. If the {@code value} isn't within the interval [min, max],
200 * no exception is thrown. In this case the method
201 * {@link LongGene#isValid()} returns {@code false}.
202 *
203 * @since 3.2
204 *
205 * @param value the value of the gene.
206 * @param range the long range to use
207 * @return a new random {@code LongGene}
208 * @throws NullPointerException if the given {@code range} is {@code null}.
209 */
210 public static LongGene of(final long value, final LongRange range) {
211 return LongGene.of(value, range.getMin(), range.getMax());
212 }
213
214 /**
215 * Create a new random {@code LongGene}. It is guaranteed that the value of
216 * the {@code LongGene} lies in the interval [min, max].
217 *
218 * @param min the minimal valid value of this gene (inclusively).
219 * @param max the maximal valid value of this gene (inclusively).
220 * @return a new {@code LongGene} with the given parameters.
221 */
222 public static LongGene of(final long min, final long max) {
223 return of(nextLong(getRandom(), min, max), min, max);
224 }
225
226 /**
227 * Create a new random {@code LongGene}. It is guaranteed that the value of
228 * the {@code LongGene} lies in the interval [min, max].
229 *
230 * @since 3.2
231 *
232 * @param range the long range to use
233 * @return a new random {@code LongGene}
234 * @throws NullPointerException if the given {@code range} is {@code null}.
235 */
236 public static LongGene of(final LongRange range) {
237 return of(nextLong(getRandom(), range.getMin(), range.getMax()), range);
238 }
239
240 static ISeq<LongGene> seq(
241 final long min,
242 final long max,
243 final IntRange lengthRange
244 ) {
245 final Random r = getRandom();
246
247 return MSeq.<LongGene>ofLength(random.nextInt(lengthRange, r))
248 .fill(() -> LongGene.of(nextLong(r, min, max), min, max))
249 .toISeq();
250 }
251
252 /**
253 * Returns a pseudo-random, uniformly distributed int value between min
254 * and max (min and max included).
255 *
256 * @param random the random engine to use for calculating the random
257 * long value
258 * @param min lower bound for generated long integer
259 * @param max upper bound for generated long integer
260 * @return a random long integer greater than or equal to {@code min}
261 * and less than or equal to {@code max}
262 * @throws IllegalArgumentException if {@code min > max}
263 * @throws NullPointerException if the given {@code random}
264 * engine is {@code null}.
265 */
266 static long nextLong(
267 final Random random,
268 final long min, final long max
269 ) {
270 if (min > max) {
271 throw new IllegalArgumentException(format(
272 "min >= max: %d >= %d.", min, max
273 ));
274 }
275
276 final long diff = (max - min) + 1;
277 long result = 0;
278
279 if (diff <= 0) {
280 do {
281 result = random.nextLong();
282 } while (result < min || result > max);
283 } else if (diff < Integer.MAX_VALUE) {
284 result = random.nextInt((int)diff) + min;
285 } else {
286 result = nextLong(random, diff) + min;
287 }
288
289 return result;
290 }
291
292 /**
293 * Returns a pseudo-random, uniformly distributed int value between 0
294 * (inclusive) and the specified value (exclusive), drawn from the given
295 * random number generator's sequence.
296 *
297 * @param random the random engine used for creating the random number.
298 * @param n the bound on the random number to be returned. Must be
299 * positive.
300 * @return the next pseudo-random, uniformly distributed int value
301 * between 0 (inclusive) and n (exclusive) from the given random
302 * number generator's sequence
303 * @throws IllegalArgumentException if n is smaller than 1.
304 * @throws NullPointerException if the given {@code random}
305 * engine is {@code null}.
306 */
307 static long nextLong(final Random random, final long n) {
308 if (n <= 0) {
309 throw new IllegalArgumentException(format(
310 "n is smaller than one: %d", n
311 ));
312 }
313
314 long bits;
315 long result;
316 do {
317 bits = random.nextLong() & 0x7fffffffffffffffL;
318 result = bits%n;
319 } while (bits - result + (n - 1) < 0);
320
321 return result;
322 }
323
324 }
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