XorShift128PlusRandomGenerator (dsiutil 2.3.3)

java.lang.Object
- org.apache.commons.math3.random.AbstractRandomGenerator
- - it.unimi.dsi.util.XorShift128PlusRandomGenerator

All Implemented Interfaces:

RandomGenerator

Deprecated.
Please use XoRoShiRo128PlusRandomGenerator instead.
```
@Deprecated
public class XorShift128PlusRandomGenerator
extends AbstractRandomGenerator
```
A fast, high-quality pseudorandom number generator that returns the sum of consecutive outputs of a Marsaglia Xorshift generator (described in “Xorshift RNGs”, Journal of Statistical Software, 8:1−6, 2003) with 128 bits of state.
Warning: this generator has been superseded by XoRoShiRo128PlusRandom, which is faster and has stronger statistical properties.
More details can be found in my paper “Further scramblings of Marsaglia's xorshift generators”, 2015, and on the xoroshiro+/xorshift*/xorshift+ generators and the PRNG shootout page. The basic idea is taken from Mutsuo Saito and Makuto Matsumoto's XSadd generator, which is however based on 32-bit shifts and fails several statistical tests when reversed.
Note that this is not a cryptographic-strength pseudorandom number generator, but its quality is preposterously higher than Random's, and its cycle length is 2¹²⁸ − 1, which is more than enough for any single-thread application.
By using the supplied jump() method it is possible to generate non-overlapping long sequences for parallel computations. This class provides also a split() method to support recursive parallel computations, in the spirit of Java 8's SplittableRandom.

See Also:

it.unimi.dsi.util, RandomGenerator, XorShift128PlusRandom

Constructor Summary

Constructors
Constructor and Description
`XorShift128PlusRandomGenerator()` Deprecated. Creates a new generator seeded using `Util.randomSeed()`.
`XorShift128PlusRandomGenerator(long seed)` Deprecated. Creates a new generator using a given seed.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`void`	`jump()` Deprecated. The the jump function for this generator.
`static void`	`main(String[] arg)` Deprecated.
`boolean`	`nextBoolean()` Deprecated.
`void`	`nextBytes(byte[] bytes)` Deprecated.
`double`	`nextDouble()` Deprecated.
`float`	`nextFloat()` Deprecated.
`int`	`nextInt()` Deprecated.
`int`	`nextInt(int n)` Deprecated.
`long`	`nextLong()` Deprecated.
`long`	`nextLong(long n)` Deprecated. Returns a pseudorandom uniformly distributed `long` value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
`void`	`setSeed(long seed)` Deprecated. Sets the seed of this generator.
`void`	`setState(long[] state)` Deprecated. Sets the state of this generator.
`XorShift128PlusRandomGenerator`	`split()` Deprecated. Returns a new instance that shares no mutable state with this instance.

Methods inherited from class org.apache.commons.math3.random.AbstractRandomGenerator
clear, nextGaussian, setSeed, setSeed

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - XorShift128PlusRandomGenerator
```
public XorShift128PlusRandomGenerator()
```
    Deprecated.
    
    Creates a new generator seeded using Util.randomSeed().
  - XorShift128PlusRandomGenerator
```
public XorShift128PlusRandomGenerator(long seed)
```
    Deprecated.
    
    Creates a new generator using a given seed.
    
    Parameters:
    
    seed - a nonzero seed for the generator (if zero, the generator will be seeded with -1).
- Method Detail
  - nextLong
```
public long nextLong()
```
    Deprecated.
    
    Specified by:
    
    nextLong in interface RandomGenerator
    
    Overrides:
    
    nextLong in class AbstractRandomGenerator
  - nextInt
```
public int nextInt()
```
    Deprecated.
    
    Specified by:
    
    nextInt in interface RandomGenerator
    
    Overrides:
    
    nextInt in class AbstractRandomGenerator
  - nextInt
```
public int nextInt(int n)
```
    Deprecated.
    
    Specified by:
    
    nextInt in interface RandomGenerator
    
    Overrides:
    
    nextInt in class AbstractRandomGenerator
  - nextLong
```
public long nextLong(long n)
```
    Deprecated.
    
    Returns a pseudorandom uniformly distributed long value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence. The algorithm used to generate the value guarantees that the result is uniform, provided that the sequence of 64-bit values produced by this generator is.
    
    Parameters:
    
    n - the positive bound on the random number to be returned.
    
    Returns:
    
    the next pseudorandom long value between 0 (inclusive) and n (exclusive).
  - nextDouble
```
public double nextDouble()
```
    Deprecated.
    
    Specified by:
    
    nextDouble in interface RandomGenerator
    
    Specified by:
    
    nextDouble in class AbstractRandomGenerator
  - nextFloat
```
public float nextFloat()
```
    Deprecated.
    
    Specified by:
    
    nextFloat in interface RandomGenerator
    
    Overrides:
    
    nextFloat in class AbstractRandomGenerator
  - nextBoolean
```
public boolean nextBoolean()
```
    Deprecated.
    
    Specified by:
    
    nextBoolean in interface RandomGenerator
    
    Overrides:
    
    nextBoolean in class AbstractRandomGenerator
  - nextBytes
```
public void nextBytes(byte[] bytes)
```
    Deprecated.
    
    Specified by:
    
    nextBytes in interface RandomGenerator
    
    Overrides:
    
    nextBytes in class AbstractRandomGenerator
  - jump
```
public void jump()
```
    Deprecated.
    
    The the jump function for this generator. It is equivalent to 2⁶⁴ calls to nextLong(); it can be used to generate 2⁶⁴ non-overlapping subsequences for parallel computations.
  - split
```
public XorShift128PlusRandomGenerator split()
```
    Deprecated.
    
    Returns a new instance that shares no mutable state with this instance. The sequence generated by the new instance depends deterministically from the state of this instance, but the probability that the sequence generated by this instance and by the new instance overlap is negligible.
    
    Returns:
    
    the new instance.
  - setSeed
```
public void setSeed(long seed)
```
    Deprecated.
    
    Sets the seed of this generator.
    The argument will be used to seed a SplitMix64RandomGenerator, whose output will in turn be used to seed this generator. This approach makes “warmup” unnecessary, and makes the probability of starting from a state with a large fraction of bits set to zero astronomically small.
    
    Specified by:
    
    setSeed in interface RandomGenerator
    
    Specified by:
    
    setSeed in class AbstractRandomGenerator
    
    Parameters:
    
    seed - a nonzero seed for this generator.
  - setState
```
public void setState(long[] state)
```
    Deprecated.
    
    Sets the state of this generator.
    The internal state of the generator will be reset, and the state array filled with the provided array.
    
    Parameters:
    
    state - an array of 2 longs; at least one must be nonzero.
  - main
```
public static void main(String[] arg)
```
    Deprecated.

Class XorShift128PlusRandomGenerator

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.math3.random.AbstractRandomGenerator

Methods inherited from class java.lang.Object

Constructor Detail

XorShift128PlusRandomGenerator

XorShift128PlusRandomGenerator

Method Detail

nextLong

nextInt

nextInt

nextLong

nextDouble

nextFloat

nextBoolean

nextBytes

jump

split

setSeed

setState

main