## Class RandomEngine

• All Implemented Interfaces:
Serializable, Cloneable, DoubleUnaryOperator, IntUnaryOperator
Direct Known Subclasses:
MersenneTwister

public abstract class RandomEngine
extends Object
implements DoubleUnaryOperator, IntUnaryOperator
Abstract base class for uniform pseudo-random number generating engines.

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
MersenneTwister, MersenneTwister64, Random, Serialized Form
• ### Constructor Summary

Constructors
Modifier Constructor Description
protected  RandomEngine()
Makes this class non instantiable, but still let's others inherit from it.
• ### Method Summary

All Methods
Modifier and Type Method Description
double applyAsDouble​(double dummy)
Equivalent to raw().
int applyAsInt​(int dummy)
Equivalent to nextInt().
Object clone()
Returns a copy of the receiver.
static RandomEngine makeDefault()
Constructs and returns a new uniform random number engine seeded with the current time.
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).
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).
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 java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
• ### Methods inherited from interface java.util.function.DoubleUnaryOperator

andThen, compose
• ### Methods inherited from interface java.util.function.IntUnaryOperator

andThen, compose
• ### Constructor Detail

• #### RandomEngine

protected RandomEngine()
Makes this class non instantiable, but still let's others inherit from it.
• ### Method Detail

• #### applyAsDouble

public double applyAsDouble​(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:
applyAsDouble in interface DoubleUnaryOperator
• #### applyAsInt

public int applyAsInt​(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:
applyAsInt in interface IntUnaryOperator
• #### makeDefault

public static RandomEngine makeDefault()
Constructs and returns a new uniform random number engine seeded with the current time. Currently this is MersenneTwister.
Returns:
the engine
• #### 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).
Returns:
the random number
• #### 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).
Returns:
the random number
• #### 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);
Returns:
the random number
• #### 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).
Returns:
the random number
• #### 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).
Returns:
the random number
• #### clone

public Object clone()
Returns a copy of the receiver. This default implementation does not nothing except making the otherwise protected clone method public.
Overrides:
clone in class Object
Returns: