01 /*
02 * Java Genetic Algorithm Library (jenetics-1.6.0).
03 * Copyright (c) 2007-2014 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.internal.math;
21
22 import org.jenetics.util.StaticObject;
23
24 /**
25 * Some random helper functions.
26 *
27 * @author <a href="mailto:franz.wilhelmstoetter@gmx.at">Franz Wilhelmstötter</a>
28 * @since 1.4
29 * @version 1.4 — <em>$Date: 2014-02-15 $</em>
30 */
31 public final class random extends StaticObject {
32 private random() {}
33
34 /*
35 * Conversion methods used by the 'Random' engine from the JDK.
36 */
37
38 public static float toFloat(final int a) {
39 return (a >>> 8)/((float)(1 << 24));
40 }
41
42 public static float toFloat(final long a) {
43 return (int)(a >>> 40)/((float)(1 << 24));
44 }
45
46 public static double toDouble(final long a) {
47 return (((a >>> 38) << 27) + (((int)a) >>> 5))/(double)(1L << 53);
48 }
49
50 public static double toDouble(final int a, final int b) {
51 return (((long)(a >>> 6) << 27) + (b >>> 5))/(double)(1L << 53);
52 }
53
54 /*
55 * Conversion methods used by the Apache Commons BitStreamGenerator.
56 */
57
58 public static float toFloat2(final int a) {
59 return (a >>> 9)*0x1.0p-23f;
60 }
61
62 public static float toFloat2(final long a) {
63 return (int)(a >>> 41)*0x1.0p-23f;
64 }
65
66 public static double toDouble2(final long a) {
67 return (a & 0xFFFFFFFFFFFFFL)*0x1.0p-52d;
68 }
69
70 public static double toDouble2(final int a, final int b) {
71 return (((long)(a >>> 6) << 26) | (b >>> 6))*0x1.0p-52d;
72 }
73
74 }
|