Class XorShift1024Star
- java.lang.Object
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- org.apache.commons.rng.core.BaseProvider
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- org.apache.commons.rng.core.source64.LongProvider
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- org.apache.commons.rng.core.source64.XorShift1024Star
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- All Implemented Interfaces:
RandomLongSource
,JumpableUniformRandomProvider
,RestorableUniformRandomProvider
,UniformRandomProvider
- Direct Known Subclasses:
XorShift1024StarPhi
public class XorShift1024Star extends LongProvider implements JumpableUniformRandomProvider
A fast RNG implementing theXorShift1024*
algorithm.Note: This has been superseded by
XorShift1024StarPhi
. The sequences emitted by both generators are correlated.- Since:
- 1.0
- See Also:
- Original source code, Xorshift (Wikipedia)
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Field Summary
Fields Modifier and Type Field Description private int
index
Index in "state" array.private static long[]
JUMP_COEFFICIENTS
The coefficients for the jump function.private long
multiplier
The multiplier for the XorShift1024 algorithm.private static int
SEED_SIZE
Size of the state vector.private long[]
state
State.
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Constructor Summary
Constructors Modifier Constructor Description XorShift1024Star(long[] seed)
Creates a new instance.protected
XorShift1024Star(long[] seed, long multiplier)
Creates a new instance.protected
XorShift1024Star(XorShift1024Star source)
Creates a copy instance.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected XorShift1024Star
copy()
Create a copy.protected byte[]
getStateInternal()
Creates a snapshot of the RNG state.UniformRandomProvider
jump()
Creates a copy of the UniformRandomProvider and then advances the state of the current instance.long
next()
Return the next random value.private void
performJump()
Perform the jump to advance the generator state.private void
setSeedInternal(long[] seed)
Seeds the RNG.protected void
setStateInternal(byte[] s)
Resets the RNG to the givenstate
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Methods inherited from class org.apache.commons.rng.core.source64.LongProvider
nextBoolean, nextInt, nextLong, resetCachedState
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Methods inherited from class org.apache.commons.rng.core.BaseProvider
checkIndex, checkStateSize, composeStateInternal, extendSeed, extendSeed, fillState, fillState, restoreState, saveState, splitStateInternal, toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.apache.commons.rng.JumpableUniformRandomProvider
jumps, jumps
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Methods inherited from interface org.apache.commons.rng.UniformRandomProvider
doubles, doubles, doubles, doubles, ints, ints, ints, ints, longs, longs, longs, longs, nextBoolean, nextBytes, nextBytes, nextDouble, nextDouble, nextDouble, nextFloat, nextFloat, nextFloat, nextInt, nextInt, nextInt, nextLong, nextLong, nextLong
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Field Detail
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SEED_SIZE
private static final int SEED_SIZE
Size of the state vector.- See Also:
- Constant Field Values
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JUMP_COEFFICIENTS
private static final long[] JUMP_COEFFICIENTS
The coefficients for the jump function.
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state
private final long[] state
State.
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multiplier
private final long multiplier
The multiplier for the XorShift1024 algorithm.
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index
private int index
Index in "state" array.
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Constructor Detail
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XorShift1024Star
public XorShift1024Star(long[] seed)
Creates a new instance.- Parameters:
seed
- Initial seed. If the length is larger than 16, only the first 16 elements will be used; if smaller, the remaining elements will be automatically set. A seed containing all zeros will create a non-functional generator.
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XorShift1024Star
protected XorShift1024Star(long[] seed, long multiplier)
Creates a new instance.- Parameters:
seed
- Initial seed. If the length is larger than 16, only the first 16 elements will be used; if smaller, the remaining elements will be automatically set. A seed containing all zeros will create a non-functional generator.multiplier
- The multiplier for the XorShift1024 algorithm.- Since:
- 1.3
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XorShift1024Star
protected XorShift1024Star(XorShift1024Star source)
Creates a copy instance.- Parameters:
source
- Source to copy.- Since:
- 1.3
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Method Detail
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getStateInternal
protected byte[] getStateInternal()
Creates a snapshot of the RNG state.- Overrides:
getStateInternal
in classLongProvider
- Returns:
- the internal state.
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setStateInternal
protected void setStateInternal(byte[] s)
Resets the RNG to the givenstate
.- Overrides:
setStateInternal
in classLongProvider
- Parameters:
s
- State (previously obtained by a call toBaseProvider.getStateInternal()
).- See Also:
BaseProvider.checkStateSize(byte[],int)
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setSeedInternal
private void setSeedInternal(long[] seed)
Seeds the RNG.- Parameters:
seed
- Seed.
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next
public long next()
Return the next random value.- Specified by:
next
in interfaceRandomLongSource
- Returns:
- the next random value.
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jump
public UniformRandomProvider jump()
Creates a copy of the UniformRandomProvider and then advances the state of the current instance. The copy is returned.The current state will be advanced in a single operation by the equivalent of a number of sequential calls to a method that updates the state of the provider. The size of the jump is implementation dependent.
Repeat invocations of this method will create a series of generators that are uniformly spaced at intervals of the output sequence. Each generator provides non-overlapping output for the length of the jump for use in parallel computations.
The jump size is the equivalent of 2512 calls to
nextLong()
. It can provide up to 2512 non-overlapping subsequences.- Specified by:
jump
in interfaceJumpableUniformRandomProvider
- Returns:
- A copy of the current state.
- Since:
- 1.3
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copy
protected XorShift1024Star copy()
Create a copy.- Returns:
- the copy
- Since:
- 1.3
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performJump
private void performJump()
Perform the jump to advance the generator state. Resets the cached state of the generator.
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