001 /*
002 * Java Genetic Algorithm Library (jenetics-4.4.0).
003 * Copyright (c) 2007-2019 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 /**
100 * Return the range of {@code this} gene.
101 *
102 * @since 4.4
103 *
104 * @return the range of {@code this} gene
105 */
106 public LongRange range() {
107 return LongRange.of(_min, _max);
108 }
109
110 @Override
111 public byte byteValue() {
112 return (byte)_value;
113 }
114
115 @Override
116 public short shortValue() {
117 return (short)_value;
118 }
119
120 @Override
121 public int intValue() {
122 return (int)_value;
123 }
124
125 @Override
126 public long longValue() {
127 return _value;
128 }
129
130 @Override
131 public float floatValue() {
132 return (float)_value;
133 }
134
135 @Override
136 public double doubleValue() {
137 return _value;
138 }
139
140 @Override
141 public boolean isValid() {
142 return _value >= _min && _value <= _max;
143 }
144
145 @Override
146 public int compareTo(final LongGene other) {
147 return Long.compare(_value, other._value);
148 }
149
150 @Override
151 public LongGene newInstance(final Long number) {
152 return LongGene.of(number, _min, _max);
153 }
154
155 @Override
156 public LongGene newInstance(final Number number) {
157 return LongGene.of(number.longValue(), _min, _max);
158 }
159
160 @Override
161 public LongGene newInstance() {
162 return LongGene.of(nextLong(getRandom(), _min, _max), _min, _max);
163 }
164
165 @Override
166 public LongGene mean(final LongGene that) {
167 return LongGene.of(_value + (that._value - _value)/2, _min, _max);
168 }
169
170 @Override
171 public int hashCode() {
172 return hash(_value, hash(_min, hash(_max, hash(getClass()))));
173 }
174
175 @Override
176 public boolean equals(final Object obj) {
177 return obj == this ||
178 obj instanceof LongGene &&
179 ((LongGene)obj)._value == _value &&
180 ((LongGene)obj)._min == _min &&
181 ((LongGene)obj)._max == _max;
182 }
183
184 @Override
185 public String toString() {
186 return String.format("[%s]", _value);
187 }
188
189 /* *************************************************************************
190 * Static factory methods.
191 * ************************************************************************/
192
193 /**
194 * Create a new random {@code LongGene} with the given value and the
195 * given range. If the {@code value} isn't within the interval [min, max],
196 * no exception is thrown. In this case the method
197 * {@link LongGene#isValid()} returns {@code false}.
198 *
199 * @param value the value of the gene.
200 * @param min the minimal valid value of this gene (inclusively).
201 * @param max the maximal valid value of this gene (inclusively).
202 * @return a new {@code LongGene} with the given parameters.
203 */
204 public static LongGene of(final long value, final long min, final long max) {
205 return new LongGene(value, min, max);
206 }
207
208 /**
209 * Create a new random {@code LongGene} with the given value and the
210 * given range. If the {@code value} isn't within the interval [min, max],
211 * no exception is thrown. In this case the method
212 * {@link LongGene#isValid()} returns {@code false}.
213 *
214 * @since 3.2
215 *
216 * @param value the value of the gene.
217 * @param range the long range to use
218 * @return a new random {@code LongGene}
219 * @throws NullPointerException if the given {@code range} is {@code null}.
220 */
221 public static LongGene of(final long value, final LongRange range) {
222 return LongGene.of(value, range.getMin(), range.getMax());
223 }
224
225 /**
226 * Create a new random {@code LongGene}. It is guaranteed that the value of
227 * the {@code LongGene} lies in the interval [min, max].
228 *
229 * @param min the minimal valid value of this gene (inclusively).
230 * @param max the maximal valid value of this gene (inclusively).
231 * @return a new {@code LongGene} with the given parameters.
232 */
233 public static LongGene of(final long min, final long max) {
234 return of(nextLong(getRandom(), min, max), min, max);
235 }
236
237 /**
238 * Create a new random {@code LongGene}. It is guaranteed that the value of
239 * the {@code LongGene} lies in the interval [min, max].
240 *
241 * @since 3.2
242 *
243 * @param range the long range to use
244 * @return a new random {@code LongGene}
245 * @throws NullPointerException if the given {@code range} is {@code null}.
246 */
247 public static LongGene of(final LongRange range) {
248 return of(nextLong(getRandom(), range.getMin(), range.getMax()), range);
249 }
250
251 static ISeq<LongGene> seq(
252 final long min,
253 final long max,
254 final IntRange lengthRange
255 ) {
256 final Random r = getRandom();
257
258 return MSeq.<LongGene>ofLength(random.nextInt(lengthRange, r))
259 .fill(() -> LongGene.of(nextLong(r, min, max), min, max))
260 .toISeq();
261 }
262
263 /**
264 * Returns a pseudo-random, uniformly distributed int value between min
265 * and max (min and max included).
266 *
267 * @param random the random engine to use for calculating the random
268 * long value
269 * @param min lower bound for generated long integer
270 * @param max upper bound for generated long integer
271 * @return a random long integer greater than or equal to {@code min}
272 * and less than or equal to {@code max}
273 * @throws IllegalArgumentException if {@code min > max}
274 * @throws NullPointerException if the given {@code random}
275 * engine is {@code null}.
276 */
277 static long nextLong(
278 final Random random,
279 final long min, final long max
280 ) {
281 if (min > max) {
282 throw new IllegalArgumentException(format(
283 "min >= max: %d >= %d.", min, max
284 ));
285 }
286
287 final long diff = (max - min) + 1;
288 long result = 0;
289
290 if (diff <= 0) {
291 do {
292 result = random.nextLong();
293 } while (result < min || result > max);
294 } else if (diff < Integer.MAX_VALUE) {
295 result = random.nextInt((int)diff) + min;
296 } else {
297 result = nextLong(random, diff) + min;
298 }
299
300 return result;
301 }
302
303 /**
304 * Returns a pseudo-random, uniformly distributed int value between 0
305 * (inclusive) and the specified value (exclusive), drawn from the given
306 * random number generator's sequence.
307 *
308 * @param random the random engine used for creating the random number.
309 * @param n the bound on the random number to be returned. Must be
310 * positive.
311 * @return the next pseudo-random, uniformly distributed int value
312 * between 0 (inclusive) and n (exclusive) from the given random
313 * number generator's sequence
314 * @throws IllegalArgumentException if n is smaller than 1.
315 * @throws NullPointerException if the given {@code random}
316 * engine is {@code null}.
317 */
318 static long nextLong(final Random random, final long n) {
319 if (n <= 0) {
320 throw new IllegalArgumentException(format(
321 "n is smaller than one: %d", n
322 ));
323 }
324
325 long bits;
326 long result;
327 do {
328 bits = random.nextLong() & 0x7fffffffffffffffL;
329 result = bits%n;
330 } while (bits - result + (n - 1) < 0);
331
332 return result;
333 }
334
335 }
|