Class MersenneTwister
- All Implemented Interfaces:
Serializable
,RandomGenerator
This generator features an extremely long period (219937-1) and 623-dimensional equidistribution up to 32 bits accuracy. The home page for this generator is located at http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html.
This generator is described in a paper by Makoto Matsumoto and Takuji Nishimura in 1998: 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
This class is mainly a Java port of the 2002-01-26 version of the generator written in C by Makoto Matsumoto and Takuji Nishimura. Here is their original copyright:
Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, All rights reserved. |
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
|
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 OWNER 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. |
- Since:
- 2.0
- See Also:
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Constructor Summary
ConstructorsConstructorDescriptionCreates a new random number generator.MersenneTwister
(int seed) Creates a new random number generator using a single int seed.MersenneTwister
(int[] seed) Creates a new random number generator using an int array seed.MersenneTwister
(long seed) Creates a new random number generator using a single long seed. -
Method Summary
Modifier and TypeMethodDescriptionprotected int
next
(int bits) Generate next pseudorandom number.void
setSeed
(int seed) Reinitialize the generator as if just built with the given int seed.void
setSeed
(int[] seed) Reinitialize the generator as if just built with the given int array seed.void
setSeed
(long seed) Reinitialize the generator as if just built with the given long seed.Methods inherited from class org.apache.commons.math3.random.BitsStreamGenerator
clear, nextBoolean, nextBytes, nextBytes, nextDouble, nextFloat, nextGaussian, nextInt, nextInt, nextLong, nextLong
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Constructor Details
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MersenneTwister
public MersenneTwister()Creates a new random number generator.The instance is initialized using the current time plus the system identity hash code of this instance as the seed.
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MersenneTwister
public MersenneTwister(int seed) Creates a new random number generator using a single int seed.- Parameters:
seed
- the initial seed (32 bits integer)
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MersenneTwister
public MersenneTwister(int[] seed) Creates a new random number generator using an int array seed.- Parameters:
seed
- the initial seed (32 bits integers array), if null the seed of the generator will be related to the current time
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MersenneTwister
public MersenneTwister(long seed) Creates a new random number generator using a single long seed.- Parameters:
seed
- the initial seed (64 bits integer)
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Method Details
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setSeed
public void setSeed(int seed) Reinitialize the generator as if just built with the given int seed.The state of the generator is exactly the same as a new generator built with the same seed.
- Specified by:
setSeed
in interfaceRandomGenerator
- Specified by:
setSeed
in classBitsStreamGenerator
- Parameters:
seed
- the initial seed (32 bits integer)
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setSeed
public void setSeed(int[] seed) Reinitialize the generator as if just built with the given int array seed.The state of the generator is exactly the same as a new generator built with the same seed.
- Specified by:
setSeed
in interfaceRandomGenerator
- Specified by:
setSeed
in classBitsStreamGenerator
- Parameters:
seed
- the initial seed (32 bits integers array), if null the seed of the generator will be the current system time plus the system identity hash code of this instance
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setSeed
public void setSeed(long seed) Reinitialize the generator as if just built with the given long seed.The state of the generator is exactly the same as a new generator built with the same seed.
- Specified by:
setSeed
in interfaceRandomGenerator
- Specified by:
setSeed
in classBitsStreamGenerator
- Parameters:
seed
- the initial seed (64 bits integer)
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next
protected int next(int bits) Generate next pseudorandom number.This method is the core generation algorithm. It is used by all the public generation methods for the various primitive types
BitsStreamGenerator.nextBoolean()
,BitsStreamGenerator.nextBytes(byte[])
,BitsStreamGenerator.nextDouble()
,BitsStreamGenerator.nextFloat()
,BitsStreamGenerator.nextGaussian()
,BitsStreamGenerator.nextInt()
,next(int)
andBitsStreamGenerator.nextLong()
.- Specified by:
next
in classBitsStreamGenerator
- Parameters:
bits
- number of random bits to produce- Returns:
- random bits generated
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