public class XorShift128PlusRandomGenerator extends AbstractRandomGenerator
More details about xorshift+ generators can be found in my
paper “Further scramblings
of Marsaglia's xorshift generators”, 2014. 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.
The methods of this class returns the same sequences as those of
XorShift128PlusRandom, to which documentation we refer for more details,
but this class is not a subclass of Random,
which unfortunately suffers from a very poor design and is very heavy on memory.
If you need a large number of generators that do not need to be an instance
of Random, or simply if you need a RandomGenerator to use
with Commons Math,
you might be wanting this class instead of XorShift128PlusRandom.
XorShift128PlusRandom| Constructor and Description |
|---|
XorShift128PlusRandomGenerator()
Creates a new generator seeded using
Util.randomSeed(). |
XorShift128PlusRandomGenerator(long seed)
Creates a new generator using a given seed.
|
| Modifier and Type | Method and Description |
|---|---|
boolean |
nextBoolean() |
void |
nextBytes(byte[] bytes) |
double |
nextDouble() |
float |
nextFloat() |
int |
nextInt() |
int |
nextInt(int n) |
long |
nextLong() |
long |
nextLong(long n)
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)
Sets the seed of this generator.
|
void |
setState(long[] state)
Sets the state of this generator.
|
clear, nextGaussian, setSeed, setSeedpublic XorShift128PlusRandomGenerator()
Util.randomSeed().public XorShift128PlusRandomGenerator(long seed)
seed - a nonzero seed for the generator (if zero, the generator will be seeded with -1).public long nextLong()
nextLong in interface RandomGeneratornextLong in class AbstractRandomGeneratorpublic int nextInt()
nextInt in interface RandomGeneratornextInt in class AbstractRandomGeneratorpublic int nextInt(int n)
nextInt in interface RandomGeneratornextInt in class AbstractRandomGeneratorpublic long nextLong(long n)
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.n - the positive bound on the random number to be returned.long value between 0 (inclusive) and n (exclusive).public double nextDouble()
nextDouble in interface RandomGeneratornextDouble in class AbstractRandomGeneratorpublic float nextFloat()
nextFloat in interface RandomGeneratornextFloat in class AbstractRandomGeneratorpublic boolean nextBoolean()
nextBoolean in interface RandomGeneratornextBoolean in class AbstractRandomGeneratorpublic void nextBytes(byte[] bytes)
nextBytes in interface RandomGeneratornextBytes in class AbstractRandomGeneratorpublic void setSeed(long seed)
The seed will be passed twice through HashCommon.murmurHash3(long). In this way, if the
user passes a small value we will avoid the short irregular transient associated
with states with a very small number of bits set.
setSeed in interface RandomGeneratorsetSeed in class AbstractRandomGeneratorseed - a nonzero seed for this generator (if zero, the generator will be seeded with Long.MIN_VALUE).public void setState(long[] state)
The internal state of the generator will be reset, and the state array filled with the provided array.
state - an array of 16 longs; at least one must be nonzero.