Package it.unimi.dsi.util
Class SplitMix64RandomGenerator
java.lang.Object
org.apache.commons.math3.random.AbstractRandomGenerator
it.unimi.dsi.util.SplitMix64RandomGenerator
- All Implemented Interfaces:
Serializable
,RandomGenerator
A fast, high-quality, non-splittable version of the SplitMix
pseudorandom number generator used by
SplittableRandom
. Due to
the fixed increment constant and to different strategies in generating finite ranges, the methods of this generator
are usually faster than those of SplittableRandom
.
Note that this generator has a relatively short period (264) so it should not be used to generate very long sequences (the rule of thumb to have a period greater than the square of the length of the sequence you want to generate).
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Constructor Summary
ConstructorDescriptionCreates a new generator seeded usingUtil.randomSeed()
.SplitMix64RandomGenerator
(long seed) Creates a new generator using a given seed. -
Method Summary
Modifier and TypeMethodDescriptionstatic void
boolean
void
nextBytes
(byte[] bytes) double
float
int
nextInt()
int
nextInt
(int n) long
nextLong()
long
nextLong
(long n) Returns a pseudorandom uniformly distributedlong
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.Methods inherited from class org.apache.commons.math3.random.AbstractRandomGenerator
clear, nextGaussian, setSeed, setSeed
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Constructor Details
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SplitMix64RandomGenerator
public SplitMix64RandomGenerator()Creates a new generator seeded usingUtil.randomSeed()
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SplitMix64RandomGenerator
public SplitMix64RandomGenerator(long seed) Creates a new generator using a given seed.- Parameters:
seed
- a seed for the generator.
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Method Details
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nextLong
public long nextLong()- Specified by:
nextLong
in interfaceRandomGenerator
- Overrides:
nextLong
in classAbstractRandomGenerator
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nextInt
public int nextInt()- Specified by:
nextInt
in interfaceRandomGenerator
- Overrides:
nextInt
in classAbstractRandomGenerator
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nextInt
public int nextInt(int n) - Specified by:
nextInt
in interfaceRandomGenerator
- Overrides:
nextInt
in classAbstractRandomGenerator
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nextLong
public long nextLong(long n) Returns a pseudorandom uniformly distributedlong
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 between0
(inclusive) andn
(exclusive).
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nextDouble
public double nextDouble()- Specified by:
nextDouble
in interfaceRandomGenerator
- Specified by:
nextDouble
in classAbstractRandomGenerator
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nextFloat
public float nextFloat()- Specified by:
nextFloat
in interfaceRandomGenerator
- Overrides:
nextFloat
in classAbstractRandomGenerator
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nextBoolean
public boolean nextBoolean()- Specified by:
nextBoolean
in interfaceRandomGenerator
- Overrides:
nextBoolean
in classAbstractRandomGenerator
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nextBytes
public void nextBytes(byte[] bytes) - Specified by:
nextBytes
in interfaceRandomGenerator
- Overrides:
nextBytes
in classAbstractRandomGenerator
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setSeed
public void setSeed(long seed) Sets the seed of this generator.The seed will be passed through
HashCommon.murmurHash3(long)
.- Specified by:
setSeed
in interfaceRandomGenerator
- Specified by:
setSeed
in classAbstractRandomGenerator
- Parameters:
seed
- a seed for this generator.
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setState
public void setState(long state) Sets the state of this generator.- Parameters:
state
- the new state for this generator (must be nonzero).
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main
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