com.orientechnologies.common.util.MersenneTwisterFast Maven / Gradle / Ivy
/*
*
* * Copyright 2014 Orient Technologies LTD (info(at)orientechnologies.com)
* *
* * Licensed 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.
* *
* * For more information: http://www.orientechnologies.com
*
*/
package com.orientechnologies.common.util;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.Serializable;
/**
* MersenneTwister and MersenneTwisterFast
*
* Version 17, based on version MT199937(99/10/29) of the Mersenne Twister algorithm found at The Mersenne Twister Home Page, with the initialization improved using
* the new 2002/1/26 initialization algorithm By Sean Luke, October 2004.
*
*
* MersenneTwister is a drop-in subclass replacement for java.util.Random. It is properly synchronized and can be used in a
* multithreaded environment. On modern VMs such as HotSpot, it is approximately 1/3 slower than java.util.Random.
*
*
* MersenneTwisterFast is not a subclass of java.util.Random. It has the same public methods as Random does, however, and it
* is algorithmically identical to MersenneTwister. MersenneTwisterFast has hard-code inlined all of its methods directly, and made
* all of them final (well, the ones of consequence anyway). Further, these methods are not synchronized, so the same
* MersenneTwisterFast instance cannot be shared by multiple threads. But all this helps MersenneTwisterFast achieve well over twice
* the speed of MersenneTwister. java.util.Random is about 1/3 slower than MersenneTwisterFast.
*
*
About the Mersenne Twister
*
* This is a Java version of the C-program for MT19937: Integer version. The MT19937 algorithm was created by Makoto Matsumoto and
* Takuji Nishimura, who ask: "When you use this, send an email to: [email protected] with an appropriate reference to your
* work". Indicate that this is a translation of their algorithm into Java.
*
*
* Reference. Makato Matsumoto and Takuji Nishimura, "Mersenne Twister: A 623-Dimensionally Equidistributed Uniform
* Pseudo-Random Number Generator", ACM Transactions on Modeling and. Computer Simulation, Vol. 8, No. 1, January 1998, pp
* 3--30.
*
*
About this Version
*
*
* Changes since V16: Added nextDouble(includeZero, includeOne) and nextFloat(includeZero, includeOne) to allow for
* half-open, fully-closed, and fully-open intervals.
*
*
* Changes Since V15: Added serialVersionUID to quiet compiler warnings from Sun's overly verbose compilers as of JDK 1.5.
*
*
* Changes Since V14: made strictfp, with StrictMath.log and StrictMath.sqrt in nextGaussian instead of Math.log and
* Math.sqrt. This is largely just to be safe, as it presently makes no difference in the speed, correctness, or results of the
* algorithm.
*
*
* Changes Since V13: clone() method CloneNotSupportedException removed.
*
*
* Changes Since V12: clone() method added.
*
*
* Changes Since V11: stateEquals(...) method added. MersenneTwisterFast is equal to other MersenneTwisterFasts with
* identical state; likewise MersenneTwister is equal to other MersenneTwister with identical state. This isn't equals(...) because
* that requires a contract of immutability to compare by value.
*
*
* Changes Since V10: A documentation error suggested that setSeed(int[]) required an int[] array 624 long. In fact, the
* array can be any non-zero length. The new version also checks for this fact.
*
*
* Changes Since V9: readState(stream) and writeState(stream) provided.
*
*
* Changes Since V8: setSeed(int) was only using the first 28 bits of the seed; it should have been 32 bits. For small-number
* seeds the behavior is identical.
*
*
* Changes Since V7: A documentation error in MersenneTwisterFast (but not MersenneTwister) stated that nextDouble selects
* uniformly from the full-open interval [0,1]. It does not. nextDouble's contract is identical across MersenneTwisterFast,
* MersenneTwister, and java.util.Random, namely, selection in the half-open interval [0,1). That is, 1.0 should not be returned. A
* similar contract exists in nextFloat.
*
*
* Changes Since V6: License has changed from LGPL to BSD. New timing information to compare against java.util.Random. Recent
* versions of HotSpot have helped Random increase in speed to the point where it is faster than MersenneTwister but slower than
* MersenneTwisterFast (which should be the case, as it's a less complex algorithm but is synchronized).
*
*
* Changes Since V5: New empty constructor made to work the same as java.util.Random -- namely, it seeds based on the current
* time in milliseconds.
*
*
* Changes Since V4: New initialization algorithms. See (see
* http://www.math.keio.ac.jp/matumoto/MT2002/emt19937ar.html)
*
*
* The MersenneTwister code is based on standard MT19937 C/C++ code by Takuji Nishimura, with suggestions from Topher Cooper and
* Marc Rieffel, July 1997. The code was originally translated into Java by Michael Lecuyer, January 1999, and the original code is
* Copyright (c) 1999 by Michael Lecuyer.
*
*
Java notes
*
*
* This implementation implements the bug fixes made in Java 1.2's version of Random, which means it can be used with earlier
* versions of Java. See the JDK 1.2
* java.util.Random documentation for further documentation on the random-number generation contracts made. Additionally,
* there's an undocumented bug in the JDK java.util.Random.nextBytes() method, which this code fixes.
*
*
* Just like java.util.Random, this generator accepts a long seed but doesn't use all of it. java.util.Random uses 48 bits. The
* Mersenne Twister instead uses 32 bits (int size). So it's best if your seed does not exceed the int range.
*
*
* MersenneTwister can be used reliably on JDK version 1.1.5 or above. Earlier Java versions have serious bugs in java.util.Random;
* only MersenneTwisterFast (and not MersenneTwister nor java.util.Random) should be used with them.
*
*
License
*
* Copyright (c) 2003 by Sean Luke.
* Portions copyright (c) 1993 by Michael Lecuyer.
* All rights reserved.
*
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
*
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided with the distribution.
*
- Neither the name of the copyright owners, their employers, nor the names of its contributors may be used to endorse or
* promote products derived from this software without specific prior written permission.
*
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT OWNERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @version 17
*/
// Note: this class is hard-inlined in all of its methods. This makes some of
// the methods well-nigh unreadable in their complexity. In fact, the Mersenne
// Twister is fairly easy code to understand: if you're trying to get a handle
// on the code, I strongly suggest looking at MersenneTwister.java first.
// -- Sean
public class MersenneTwisterFast implements Serializable, Cloneable {
// Serialization
private static final long serialVersionUID = -8219700664442619525L; // locked as of Version 15
// Period parameters
private static final int N = 624;
private static final int M = 397;
private static final int MATRIX_A = 0x9908b0df; // private static final * constant vector a
private static final int UPPER_MASK = 0x80000000; // most significant w-r bits
private static final int LOWER_MASK = 0x7fffffff; // least significant r bits
// Tempering parameters
private static final int TEMPERING_MASK_B = 0x9d2c5680;
private static final int TEMPERING_MASK_C = 0xefc60000;
private int mt[]; // the array for the state vector
private int mti; // mti==N+1 means mt[N] is not initialized
private int mag01[];
// a good initial seed (of int size, though stored in a long)
// private static final long GOOD_SEED = 4357;
private double __nextNextGaussian;
private boolean __haveNextNextGaussian;
/**
* Constructor using the default seed.
*/
public MersenneTwisterFast() {
this(System.currentTimeMillis());
}
/**
* Constructor using a given seed. Though you pass this seed in as a long, it's best to make sure it's actually an integer.
*
*/
public MersenneTwisterFast(final long seed) {
setSeed(seed);
}
/**
* Constructor using an array of integers as seed. Your array must have a non-zero length. Only the first 624 integers in the
* array are used; if the array is shorter than this then integers are repeatedly used in a wrap-around fashion.
*/
public MersenneTwisterFast(final int[] array) {
setSeed(array);
}
/* We're overriding all internal data, to my knowledge, so this should be okay */
public Object clone() {
try {
MersenneTwisterFast f = (MersenneTwisterFast) (super.clone());
f.mt = (int[]) (mt.clone());
f.mag01 = (int[]) (mag01.clone());
return f;
} catch (CloneNotSupportedException e) {
throw new InternalError();
} // should never happen
}
public boolean stateEquals(Object o) {
if (o == this)
return true;
if (o == null || !(o instanceof MersenneTwisterFast))
return false;
MersenneTwisterFast other = (MersenneTwisterFast) o;
if (mti != other.mti)
return false;
for (int x = 0; x < mag01.length; x++)
if (mag01[x] != other.mag01[x])
return false;
for (int x = 0; x < mt.length; x++)
if (mt[x] != other.mt[x])
return false;
return true;
}
/** Reads the entire state of the MersenneTwister RNG from the stream */
public void readState(DataInputStream stream) throws IOException {
int len = mt.length;
for (int x = 0; x < len; x++)
mt[x] = stream.readInt();
len = mag01.length;
for (int x = 0; x < len; x++)
mag01[x] = stream.readInt();
mti = stream.readInt();
__nextNextGaussian = stream.readDouble();
__haveNextNextGaussian = stream.readBoolean();
}
/** Writes the entire state of the MersenneTwister RNG to the stream */
public void writeState(DataOutputStream stream) throws IOException {
int len = mt.length;
for (int x = 0; x < len; x++)
stream.writeInt(mt[x]);
len = mag01.length;
for (int x = 0; x < len; x++)
stream.writeInt(mag01[x]);
stream.writeInt(mti);
stream.writeDouble(__nextNextGaussian);
stream.writeBoolean(__haveNextNextGaussian);
}
/**
* Initalize the pseudo random number generator. Don't pass in a long that's bigger than an int (Mersenne Twister only uses the
* first 32 bits for its seed).
*/
synchronized public void setSeed(final long seed) {
// Due to a bug in java.util.Random clear up to 1.2, we're
// doing our own Gaussian variable.
__haveNextNextGaussian = false;
mt = new int[N];
mag01 = new int[2];
mag01[0] = 0x0;
mag01[1] = MATRIX_A;
mt[0] = (int) (seed & 0xffffffff);
for (mti = 1; mti < N; mti++) {
mt[mti] = (1812433253 * (mt[mti - 1] ^ (mt[mti - 1] >>> 30)) + mti);
/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
/* In the previous versions, MSBs of the seed affect */
/* only MSBs of the array mt[]. */
/* 2002/01/09 modified by Makoto Matsumoto */
mt[mti] &= 0xffffffff;
/* for >32 bit machines */
}
}
/**
* Sets the seed of the MersenneTwister using an array of integers. Your array must have a non-zero length. Only the first 624
* integers in the array are used; if the array is shorter than this then integers are repeatedly used in a wrap-around fashion.
*/
synchronized public void setSeed(final int[] array) {
if (array.length == 0)
throw new IllegalArgumentException("Array length must be greater than zero");
int i, j, k;
setSeed(19650218);
i = 1;
j = 0;
k = (N > array.length ? N : array.length);
for (; k != 0; k--) {
mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >>> 30)) * 1664525)) + array[j] + j; /* non linear */
mt[i] &= 0xffffffff; /* for WORDSIZE > 32 machines */
i++;
j++;
if (i >= N) {
mt[0] = mt[N - 1];
i = 1;
}
if (j >= array.length)
j = 0;
}
for (k = N - 1; k != 0; k--) {
mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >>> 30)) * 1566083941)) - i; /* non linear */
mt[i] &= 0xffffffff; /* for WORDSIZE > 32 machines */
i++;
if (i >= N) {
mt[0] = mt[N - 1];
i = 1;
}
}
mt[0] = 0x80000000; /* MSB is 1; assuring non-zero initial array */
}
public final int nextInt() {
int y;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
return y;
}
public final short nextShort() {
int y;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
return (short) (y >>> 16);
}
public final char nextChar() {
int y;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
return (char) (y >>> 16);
}
public final boolean nextBoolean() {
int y;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
return (boolean) ((y >>> 31) != 0);
}
/**
* This generates a coin flip with a probability probability of returning true, else returning false.
* probability must be between 0.0 and 1.0, inclusive. Not as precise a random real event as nextBoolean(double), but
* twice as fast. To explicitly use this, remember you may need to cast to float first.
*/
public final boolean nextBoolean(final float probability) {
int y;
if (probability < 0.0f || probability > 1.0f)
throw new IllegalArgumentException("probability must be between 0.0 and 1.0 inclusive.");
if (probability == 0.0f)
return false; // fix half-open issues
else if (probability == 1.0f)
return true; // fix half-open issues
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
return (y >>> 8) / ((float) (1 << 24)) < probability;
}
/**
* This generates a coin flip with a probability probability of returning true, else returning false.
* probability must be between 0.0 and 1.0, inclusive.
*/
public final boolean nextBoolean(final double probability) {
int y;
int z;
if (probability < 0.0 || probability > 1.0)
throw new IllegalArgumentException("probability must be between 0.0 and 1.0 inclusive.");
if (probability == 0.0)
return false; // fix half-open issues
else if (probability == 1.0)
return true; // fix half-open issues
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (z >>> 1) ^ mag01[z & 0x1];
}
for (; kk < N - 1; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (z >>> 1) ^ mag01[z & 0x1];
}
z = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (z >>> 1) ^ mag01[z & 0x1];
mti = 0;
}
z = mt[mti++];
z ^= z >>> 11; // TEMPERING_SHIFT_U(z)
z ^= (z << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(z)
z ^= (z << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(z)
z ^= (z >>> 18); // TEMPERING_SHIFT_L(z)
/* derived from nextDouble documentation in jdk 1.2 docs, see top */
return ((((long) (y >>> 6)) << 27) + (z >>> 5)) / (double) (1L << 53) < probability;
}
public final byte nextByte() {
int y;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
return (byte) (y >>> 24);
}
public final void nextBytes(byte[] bytes) {
int y;
for (int x = 0; x < bytes.length; x++) {
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
bytes[x] = (byte) (y >>> 24);
}
}
public final long nextLong() {
int y;
int z;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (z >>> 1) ^ mag01[z & 0x1];
}
for (; kk < N - 1; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (z >>> 1) ^ mag01[z & 0x1];
}
z = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (z >>> 1) ^ mag01[z & 0x1];
mti = 0;
}
z = mt[mti++];
z ^= z >>> 11; // TEMPERING_SHIFT_U(z)
z ^= (z << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(z)
z ^= (z << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(z)
z ^= (z >>> 18); // TEMPERING_SHIFT_L(z)
return (((long) y) << 32) + (long) z;
}
/**
* Returns a long drawn uniformly from 0 to n-1. Suffice it to say, n must be > 0, or an IllegalArgumentException is raised.
*/
public final long nextLong(final long n) {
if (n <= 0)
throw new IllegalArgumentException("n must be positive, got: " + n);
long bits, val;
do {
int y;
int z;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (z >>> 1) ^ mag01[z & 0x1];
}
for (; kk < N - 1; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (z >>> 1) ^ mag01[z & 0x1];
}
z = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (z >>> 1) ^ mag01[z & 0x1];
mti = 0;
}
z = mt[mti++];
z ^= z >>> 11; // TEMPERING_SHIFT_U(z)
z ^= (z << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(z)
z ^= (z << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(z)
z ^= (z >>> 18); // TEMPERING_SHIFT_L(z)
bits = (((((long) y) << 32) + (long) z) >>> 1);
val = bits % n;
} while (bits - val + (n - 1) < 0);
return val;
}
/**
* Returns a random double in the half-open range from [0.0,1.0). Thus 0.0 is a valid result but 1.0 is not.
*/
public final double nextDouble() {
int y;
int z;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (z >>> 1) ^ mag01[z & 0x1];
}
for (; kk < N - 1; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (z >>> 1) ^ mag01[z & 0x1];
}
z = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (z >>> 1) ^ mag01[z & 0x1];
mti = 0;
}
z = mt[mti++];
z ^= z >>> 11; // TEMPERING_SHIFT_U(z)
z ^= (z << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(z)
z ^= (z << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(z)
z ^= (z >>> 18); // TEMPERING_SHIFT_L(z)
/* derived from nextDouble documentation in jdk 1.2 docs, see top */
return ((((long) (y >>> 6)) << 27) + (z >>> 5)) / (double) (1L << 53);
}
/**
* Returns a double in the range from 0.0 to 1.0, possibly inclusive of 0.0 and 1.0 themselves. Thus:
*
*
*
*
* Expression
* Interval
*
* nextDouble(false, false)
* (0.0, 1.0)
*
* nextDouble(true, false)
* [0.0, 1.0)
*
* nextDouble(false, true)
* (0.0, 1.0]
*
* nextDouble(true, true)
* [0.0, 1.0]
*
*
*
* This version preserves all possible random values in the double range.
*/
public double nextDouble(boolean includeZero, boolean includeOne) {
double d = 0.0;
do {
d = nextDouble(); // grab a value, initially from half-open [0.0, 1.0)
if (includeOne && nextBoolean())
d += 1.0; // if includeOne, with 1/2 probability, push to [1.0, 2.0)
} while ((d > 1.0) || // everything above 1.0 is always invalid
(!includeZero && d == 0.0)); // if we're not including zero, 0.0 is invalid
return d;
}
public final double nextGaussian() {
if (__haveNextNextGaussian) {
__haveNextNextGaussian = false;
return __nextNextGaussian;
} else {
double v1, v2, s;
do {
int y;
int z;
int a;
int b;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (z >>> 1) ^ mag01[z & 0x1];
}
for (; kk < N - 1; kk++) {
z = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (z >>> 1) ^ mag01[z & 0x1];
}
z = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (z >>> 1) ^ mag01[z & 0x1];
mti = 0;
}
z = mt[mti++];
z ^= z >>> 11; // TEMPERING_SHIFT_U(z)
z ^= (z << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(z)
z ^= (z << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(z)
z ^= (z >>> 18); // TEMPERING_SHIFT_L(z)
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
a = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (a >>> 1) ^ mag01[a & 0x1];
}
for (; kk < N - 1; kk++) {
a = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (a >>> 1) ^ mag01[a & 0x1];
}
a = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (a >>> 1) ^ mag01[a & 0x1];
mti = 0;
}
a = mt[mti++];
a ^= a >>> 11; // TEMPERING_SHIFT_U(a)
a ^= (a << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(a)
a ^= (a << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(a)
a ^= (a >>> 18); // TEMPERING_SHIFT_L(a)
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
b = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (b >>> 1) ^ mag01[b & 0x1];
}
for (; kk < N - 1; kk++) {
b = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (b >>> 1) ^ mag01[b & 0x1];
}
b = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (b >>> 1) ^ mag01[b & 0x1];
mti = 0;
}
b = mt[mti++];
b ^= b >>> 11; // TEMPERING_SHIFT_U(b)
b ^= (b << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(b)
b ^= (b << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(b)
b ^= (b >>> 18); // TEMPERING_SHIFT_L(b)
/* derived from nextDouble documentation in jdk 1.2 docs, see top */
v1 = 2 * (((((long) (y >>> 6)) << 27) + (z >>> 5)) / (double) (1L << 53)) - 1;
v2 = 2 * (((((long) (a >>> 6)) << 27) + (b >>> 5)) / (double) (1L << 53)) - 1;
s = v1 * v1 + v2 * v2;
} while (s >= 1 || s == 0);
double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s) / s);
__nextNextGaussian = v2 * multiplier;
__haveNextNextGaussian = true;
return v1 * multiplier;
}
}
/**
* Returns a random float in the half-open range from [0.0f,1.0f). Thus 0.0f is a valid result but 1.0f is not.
*/
public final float nextFloat() {
int y;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
return (y >>> 8) / ((float) (1 << 24));
}
/**
* Returns a float in the range from 0.0f to 1.0f, possibly inclusive of 0.0f and 1.0f themselves. Thus:
*
*
*
*
* Expression
* Interval
*
* nextFloat(false, false)
* (0.0f, 1.0f)
*
* nextFloat(true, false)
* [0.0f, 1.0f)
*
* nextFloat(false, true)
* (0.0f, 1.0f]
*
* nextFloat(true, true)
* [0.0f, 1.0f]
*
*
*
* This version preserves all possible random values in the float range.
*/
public double nextFloat(boolean includeZero, boolean includeOne) {
float d = 0.0f;
do {
d = nextFloat(); // grab a value, initially from half-open [0.0f, 1.0f)
if (includeOne && nextBoolean())
d += 1.0f; // if includeOne, with 1/2 probability, push to [1.0f, 2.0f)
} while ((d > 1.0f) || // everything above 1.0f is always invalid
(!includeZero && d == 0.0f)); // if we're not including zero, 0.0f is invalid
return d;
}
/**
* Returns an integer drawn uniformly from 0 to n-1. Suffice it to say, n must be > 0, or an IllegalArgumentException is raised.
*/
public final int nextInt(final int n) {
if (n <= 0)
throw new IllegalArgumentException("n must be positive, got: " + n);
if ((n & -n) == n) // i.e., n is a power of 2
{
int y;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
return (int) ((n * (long) (y >>> 1)) >> 31);
}
int bits, val;
do {
int y;
if (mti >= N) // generate N words at one time
{
int kk;
final int[] mt = this.mt; // locals are slightly faster
final int[] mag01 = this.mag01; // locals are slightly faster
for (kk = 0; kk < N - M; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
}
for (; kk < N - 1; kk++) {
y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
}
y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];
mti = 0;
}
y = mt[mti++];
y ^= y >>> 11; // TEMPERING_SHIFT_U(y)
y ^= (y << 7) & TEMPERING_MASK_B; // TEMPERING_SHIFT_S(y)
y ^= (y << 15) & TEMPERING_MASK_C; // TEMPERING_SHIFT_T(y)
y ^= (y >>> 18); // TEMPERING_SHIFT_L(y)
bits = (y >>> 1);
val = bits % n;
} while (bits - val + (n - 1) < 0);
return val;
}
}