Class RandomEngine
- All Implemented Interfaces:
DoubleFunction
,IntFunction
,Serializable
,Cloneable
- Direct Known Subclasses:
DRand
,MersenneTwister
Most probability distributions are obtained by using a uniform pseudo-random number generation engine followed by a transformation to the desired distribution. Thus, subclasses of this class are at the core of computational statistics, simulations, Monte Carlo methods, etc.
Subclasses produce uniformly distributed int's and long's in the closed intervals [Integer.MIN_VALUE,Integer.MAX_VALUE] and [Long.MIN_VALUE,Long.MAX_VALUE], respectively, as well as float's and double's in the open unit intervals (0.0f,1.0f) and (0.0,1.0), respectively.
Subclasses need to override one single method only: nextInt(). All other methods generating different data types or ranges are usually layered upon nextInt(). long's are formed by concatenating two 32 bit int's. float's are formed by dividing the interval [0.0f,1.0f] into 232 sub intervals, then randomly choosing one subinterval. double's are formed by dividing the interval [0.0,1.0] into 264 sub intervals, then randomly choosing one subinterval.
Note that this implementation is not synchronized.
- Version:
- 1.0, 09/24/99
- See Also:
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Field Summary
Fields inherited from class cern.colt.PersistentObject
serialVersionUID
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
Makes this class non instantiable, but still let's others inherit from it. -
Method Summary
Modifier and TypeMethodDescriptiondouble
apply
(double dummy) Equivalent to raw().int
apply
(int dummy) Equivalent to nextInt().static RandomEngine
Constructs and returns a new uniform random number engine seeded with the current time.double
Returns a 64 bit uniformly distributed random number in the open unit interval(0.0,1.0)
(excluding 0.0 and 1.0).float
Returns a 32 bit uniformly distributed random number in the open unit interval(0.0f,1.0f)
(excluding 0.0f and 1.0f).abstract int
nextInt()
Returns a 32 bit uniformly distributed random number in the closed interval [Integer.MIN_VALUE,Integer.MAX_VALUE] (including Integer.MIN_VALUE and Integer.MAX_VALUE);long
nextLong()
Returns a 64 bit uniformly distributed random number in the closed interval [Long.MIN_VALUE,Long.MAX_VALUE] (including Long.MIN_VALUE and Long.MAX_VALUE).double
raw()
Returns a 32 bit uniformly distributed random number in the open unit interval(0.0,1.0)
(excluding 0.0 and 1.0).Methods inherited from class cern.colt.PersistentObject
clone
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Constructor Details
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RandomEngine
protected RandomEngine()Makes this class non instantiable, but still let's others inherit from it.
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Method Details
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apply
public double apply(double dummy) Equivalent to raw(). This has the effect that random engines can now be used as function objects, returning a random number upon function evaluation.- Specified by:
apply
in interfaceDoubleFunction
- Parameters:
dummy
- argument passed to the function.- Returns:
- the result of the function.
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apply
public int apply(int dummy) Equivalent to nextInt(). This has the effect that random engines can now be used as function objects, returning a random number upon function evaluation.- Specified by:
apply
in interfaceIntFunction
- Parameters:
dummy
- argument passed to the function.- Returns:
- the result of the function.
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makeDefault
Constructs and returns a new uniform random number engine seeded with the current time. Currently this isMersenneTwister
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nextDouble
public double nextDouble()Returns a 64 bit uniformly distributed random number in the open unit interval(0.0,1.0)
(excluding 0.0 and 1.0). -
nextFloat
public float nextFloat()Returns a 32 bit uniformly distributed random number in the open unit interval(0.0f,1.0f)
(excluding 0.0f and 1.0f). -
nextInt
public abstract int nextInt()Returns a 32 bit uniformly distributed random number in the closed interval [Integer.MIN_VALUE,Integer.MAX_VALUE] (including Integer.MIN_VALUE and Integer.MAX_VALUE); -
nextLong
public long nextLong()Returns a 64 bit uniformly distributed random number in the closed interval [Long.MIN_VALUE,Long.MAX_VALUE] (including Long.MIN_VALUE and Long.MAX_VALUE). -
raw
public double raw()Returns a 32 bit uniformly distributed random number in the open unit interval(0.0,1.0)
(excluding 0.0 and 1.0).
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