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author | Raymond <siuchow@google.com> | 2015-04-02 10:43:13 -0700 |
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committer | Raymond <siuchow@google.com> | 2015-04-02 10:43:13 -0700 |
commit | dee0849a9704d532af0b550146cbafbaa6ee1d19 (patch) | |
tree | 8ccce3a046c214fb609977b7fc53c40cef7f9ea5 /src/main/java/org/apache/commons/math/random/Well44497b.java | |
parent | 55b0a5efc929efa9615babd3e760547f94e3518e (diff) | |
download | apache-commons-math-marshmallow-dr-dev.tar.gz |
third party library: apache-commons-mathandroid-cts-6.0_r9android-cts-6.0_r8android-cts-6.0_r7android-cts-6.0_r6android-cts-6.0_r5android-cts-6.0_r4android-cts-6.0_r32android-cts-6.0_r31android-cts-6.0_r30android-cts-6.0_r3android-cts-6.0_r29android-cts-6.0_r28android-cts-6.0_r27android-cts-6.0_r26android-cts-6.0_r25android-cts-6.0_r24android-cts-6.0_r23android-cts-6.0_r22android-cts-6.0_r21android-cts-6.0_r20android-cts-6.0_r2android-cts-6.0_r19android-cts-6.0_r18android-cts-6.0_r17android-cts-6.0_r16android-cts-6.0_r15android-cts-6.0_r14android-cts-6.0_r13android-cts-6.0_r12android-cts-6.0_r1android-6.0.1_r9android-6.0.1_r81android-6.0.1_r80android-6.0.1_r8android-6.0.1_r79android-6.0.1_r78android-6.0.1_r77android-6.0.1_r74android-6.0.1_r73android-6.0.1_r72android-6.0.1_r70android-6.0.1_r7android-6.0.1_r69android-6.0.1_r68android-6.0.1_r67android-6.0.1_r66android-6.0.1_r65android-6.0.1_r63android-6.0.1_r62android-6.0.1_r61android-6.0.1_r60android-6.0.1_r59android-6.0.1_r58android-6.0.1_r57android-6.0.1_r56android-6.0.1_r55android-6.0.1_r54android-6.0.1_r53android-6.0.1_r52android-6.0.1_r51android-6.0.1_r50android-6.0.1_r5android-6.0.1_r49android-6.0.1_r48android-6.0.1_r47android-6.0.1_r46android-6.0.1_r45android-6.0.1_r43android-6.0.1_r42android-6.0.1_r41android-6.0.1_r40android-6.0.1_r4android-6.0.1_r33android-6.0.1_r32android-6.0.1_r31android-6.0.1_r30android-6.0.1_r3android-6.0.1_r28android-6.0.1_r27android-6.0.1_r26android-6.0.1_r25android-6.0.1_r24android-6.0.1_r22android-6.0.1_r21android-6.0.1_r20android-6.0.1_r18android-6.0.1_r17android-6.0.1_r16android-6.0.1_r13android-6.0.1_r12android-6.0.1_r11android-6.0.1_r10android-6.0.1_r1android-6.0.0_r7android-6.0.0_r6android-6.0.0_r5android-6.0.0_r41android-6.0.0_r4android-6.0.0_r3android-6.0.0_r26android-6.0.0_r25android-6.0.0_r24android-6.0.0_r23android-6.0.0_r2android-6.0.0_r13android-6.0.0_r12android-6.0.0_r11android-6.0.0_r1marshmallow-releasemarshmallow-mr3-releasemarshmallow-mr2-releasemarshmallow-mr1-releasemarshmallow-mr1-devmarshmallow-dr1.6-releasemarshmallow-dr1.5-releasemarshmallow-dr1.5-devmarshmallow-dr-releasemarshmallow-dr-dragon-releasemarshmallow-dr-devmarshmallow-devmarshmallow-cts-release
Change-Id: I52a325624a7f0dd652b362a9840626d6d9f3c42b
Diffstat (limited to 'src/main/java/org/apache/commons/math/random/Well44497b.java')
-rw-r--r-- | src/main/java/org/apache/commons/math/random/Well44497b.java | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math/random/Well44497b.java b/src/main/java/org/apache/commons/math/random/Well44497b.java new file mode 100644 index 0000000..28b5dbb --- /dev/null +++ b/src/main/java/org/apache/commons/math/random/Well44497b.java @@ -0,0 +1,119 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.commons.math.random; + + +/** This class implements the WELL44497b pseudo-random number generator + * from François Panneton, Pierre L'Ecuyer and Makoto Matsumoto. + + * <p>This generator is described in a paper by François Panneton, + * Pierre L'Ecuyer and Makoto Matsumoto <a + * href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng.pdf">Improved + * Long-Period Generators Based on Linear Recurrences Modulo 2</a> ACM + * Transactions on Mathematical Software, 32, 1 (2006). The errata for the paper + * are in <a href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng-errata.txt">wellrng-errata.txt</a>.</p> + + * @see <a href="http://www.iro.umontreal.ca/~panneton/WELLRNG.html">WELL Random number generator</a> + * @version $Revision: 1003892 $ $Date: 2010-10-02 23:28:56 +0200 (sam. 02 oct. 2010) $ + * @since 2.2 + + */ +public class Well44497b extends AbstractWell { + + /** Serializable version identifier. */ + private static final long serialVersionUID = 4032007538246675492L; + + /** Number of bits in the pool. */ + private static final int K = 44497; + + /** First parameter of the algorithm. */ + private static final int M1 = 23; + + /** Second parameter of the algorithm. */ + private static final int M2 = 481; + + /** Third parameter of the algorithm. */ + private static final int M3 = 229; + + /** Creates a new random number generator. + * <p>The instance is initialized using the current time as the + * seed.</p> + */ + public Well44497b() { + super(K, M1, M2, M3); + } + + /** Creates a new random number generator using a single int seed. + * @param seed the initial seed (32 bits integer) + */ + public Well44497b(int seed) { + super(K, M1, M2, M3, seed); + } + + /** Creates a new random number generator using an int array seed. + * @param seed the initial seed (32 bits integers array), if null + * the seed of the generator will be related to the current time + */ + public Well44497b(int[] seed) { + super(K, M1, M2, M3, seed); + } + + /** Creates a new random number generator using a single long seed. + * @param seed the initial seed (64 bits integer) + */ + public Well44497b(long seed) { + super(K, M1, M2, M3, seed); + } + + /** {@inheritDoc} */ + @Override + protected int next(final int bits) { + + // compute raw value given by WELL44497a generator + // which is NOT maximally-equidistributed + final int indexRm1 = iRm1[index]; + final int indexRm2 = iRm2[index]; + + final int v0 = v[index]; + final int vM1 = v[i1[index]]; + final int vM2 = v[i2[index]]; + final int vM3 = v[i3[index]]; + + // the values below include the errata of the original article + final int z0 = (0xFFFF8000 & v[indexRm1]) ^ (0x00007FFF & v[indexRm2]); + final int z1 = (v0 ^ (v0 << 24)) ^ (vM1 ^ (vM1 >>> 30)); + final int z2 = (vM2 ^ (vM2 << 10)) ^ (vM3 << 26); + final int z3 = z1 ^ z2; + final int z2Prime = ((z2 << 9) ^ (z2 >>> 23)) & 0xfbffffff; + final int z2Second = ((z2 & 0x00020000) != 0) ? (z2Prime ^ 0xb729fcec) : z2Prime; + int z4 = z0 ^ (z1 ^ (z1 >>> 20)) ^ z2Second ^ z3; + + v[index] = z3; + v[indexRm1] = z4; + v[indexRm2] &= 0xFFFF8000; + index = indexRm1; + + // add Matsumoto-Kurita tempering + // to get a maximally-equidistributed generator + z4 = z4 ^ ((z4 << 7) & 0x93dd1400); + z4 = z4 ^ ((z4 << 15) & 0xfa118000); + + return z4 >>> (32 - bits); + + } + +} |