Package org.evoludo.math

Class RNGDistribution.Uniform

Object

RNGDistribution

Uniform

Enclosing class:

RNGDistribution

public static class RNGDistribution.Uniform
extends RNGDistribution

Uniformly distributed random numbers with support [min, max).

See Also:

• Wikipedia: Uniform distribution

Nested Class Summary

Nested classes/interfaces inherited from class RNGDistribution

RNGDistribution.Binomial, RNGDistribution.Exponential, RNGDistribution.Geometric, RNGDistribution.Gillespie, RNGDistribution.Normal, RNGDistribution.TestCommand, RNGDistribution.Uniform

Field Summary

Fields

Modifier and Type	Field	Description
private double	min	Lower bound of uniform interval (inclusive).
private double	range	Width of interval of uniform random numbers, max-min.

Fields inherited from class RNGDistribution

rng, seed, seedSet, testSamples

Constructor Summary

Constructors

Constructor	Description
Uniform()	Creates uniform random distribution in interval [0,1) with new instance of MersenneTwister.
Uniform(double min, double max)	Creates uniform random distribution in interval [min, max) with new instance of MersenneTwister.
Uniform(MersenneTwister rng, double min, double max)	Creates uniform random distribution in interval [min, max) with random number generator rng.

Method Summary

Modifier and Type	Method	Description
private static double	cdf(double x, double min, double max)	Helper method to calculate the cumulative distribution function, cdf, of the Uniform distribution.
RNGDistribution.Uniform	clone()	Clone this RNGDistribution to ensure both objects return identical sequences of random numbers.
double	getMax()	Get the upper bound of the uniform distribution (exclusive).
double	getMin()	Get the lower bound of the uniform distribution (inclusive).
double	getRange()	Get the range of the uniform distribution.
double	next()	Generate a uniformly distributed random number from interval [min, max).
static double	next(MersenneTwister rng, double min, double max)	Uniformly distributed random number in [min, max) using random number generator rng.
static void	test(MersenneTwister rng, Logger logger, MersenneTwister.Chronometer clock)	Test Uniform distribution.

Methods inherited from class RNGDistribution

clearRNGSeed, clone, getRNG, getRNGSeed, isRNGSeedSet, nextBoolean, nextByte, nextBytes, nextDouble, nextGaussian, nextInt, nextInt, random01, random01d, random0n, random0N, setRNG, setRNGSeed, setRNGSeed

Methods inherited from class Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

min

private double min

Lower bound of uniform interval (inclusive).

range

private double range

Width of interval of uniform random numbers, max-min.

Constructor Details

Uniform

public Uniform()

Creates uniform random distribution in interval [0,1) with new instance of MersenneTwister.

Uniform

public Uniform(double min,
 double max)

Creates uniform random distribution in interval [min, max) with new instance of MersenneTwister.

Parameters:

min - lower bound of uniform interval (inclusive)

max - upper bound of uniform interval (exclusive)

Uniform

public Uniform(MersenneTwister rng,
 double min,
 double max)
        throws IllegalArgumentException

Creates uniform random distribution in interval [min, max) with random number generator rng.

Parameters:

rng - random number generator

min - lower bound of uniform interval (inclusive)

max - upper bound of uniform interval (exclusive)

Throws:

IllegalArgumentException - if max≤min

See Also:

• MersenneTwister

Method Details

getMin

public double getMin()

Get the lower bound of the uniform distribution (inclusive).

Returns:

the lower bound

getMax

public double getMax()

Get the upper bound of the uniform distribution (exclusive).

Returns:

the upper bound

getRange

public double getRange()

Get the range of the uniform distribution.

Returns:

the range of the interval max-min

next

public double next()

Generate a uniformly distributed random number from interval [min, max).

Returns:

the uniformly distributed random number

clone

public RNGDistribution.Uniform clone()

Description copied from class: RNGDistribution

Clone this RNGDistribution to ensure both objects return identical sequences of random numbers.

IMPORTANT:

1. overrides clone() in Object but conflicts with GWT's aversion to clone()ing...
2. remove @SuppressWarnings("all") to ensure that no other issues crept in when modifying method.

Specified by:

clone in class RNGDistribution

Returns:

clone of RNGDistribution

next

public static double next(MersenneTwister rng,
 double min,
 double max)

Uniformly distributed random number in [min, max) using random number generator rng.

Note: no performance difference between the instance method next() and this static counterpart.

Parameters:

rng - random number generator

min - lower bound of uniform interval (inclusive)

max - upper bound of uniform interval (exclusive)

Returns:

uniformly distributed random number from interval [min, max)

Throws:

IllegalArgumentException - if max≤min

test

public static void test(MersenneTwister rng,
 Logger logger,
 MersenneTwister.Chronometer clock)

Test Uniform distribution. The test samples the distribution and bins the random numbers. This sample distribution is compared to the theoretical expectation. The mean deviation is the mean difference between the actual number of events in each bin and their expected number. For a perfect match the mean deviation is 0. The test passes if the mean deviation lies within one standard error from 0. This is more stringent than the traditional 95% confidence interval.

Parameters:

rng - the random number generator

logger - the logger for reporting results

clock - the stop watch

See Also:

• Wikipedia: Standard error

cdf

private static double cdf(double x,
 double min,
 double max)

Helper method to calculate the cumulative distribution function, cdf, of the Uniform distribution.

Parameters:

x - the value for which to calculate the cdf

min - the minimum value

max - the maximum value

Returns:

cdf at x