squidpony.squidmath

Interface IDistribution

All Known Implementing Classes:

BathtubDistribution, CurvedBoundedDistribution, ExponentialDistribution, GaussianDistribution, IDistribution.SimpleDistribution, KumaraswamyDistribution, SpikeDistribution, SpikeDistribution.SimpleSpikeDistribution

public interface IDistribution

A way to take an IRNG and get one or more random numbers from it to produce a double in some statistical distribution, such as Gaussian (also called the normal distribution), exponential, or various simpler schemes that don't have common mathematical names. An example of the last category is "spike" for a distribution that is very likely to be 0 and quickly drops off to being less likely for positive or negative results between 0 and -1 or 1, or "bathtub" for the "spike" distribution's fractional part from 0 to 1 (which is likely to be 0 or 1 and very unlikely to be near 0.5). Created by Tommy Ettinger on 11/23/2019.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	IDistribution.SimpleDistribution An abstract IDistribution that always has a lower bound of 0.0 and an upper bound of EXCLUSIVE_ONE, matching the bounds of IRNG.nextDouble().

Field Summary

Fields

Modifier and Type	Field and Description
static double	EXCLUSIVE_ONE A double that is less than 1.0 by the smallest representable amount.
static double	EXCLUSIVE_ZERO A double that is greater than 0.0 by the smallest representable amount.

Method Summary

Modifier and Type	Method and Description
double	getLowerBound() Gets the lower inclusive bound of the distribution.
double	getMean() Gets the mean value of this distribution.
double	getUpperBound() Gets the upper inclusive bound of the distribution.
double	nextDouble(IRNG rng) Gets a double between getLowerBound() and getUpperBound() that obeys this distribution.

Field Detail

EXCLUSIVE_ZERO

static final double EXCLUSIVE_ZERO

A double that is greater than 0.0 by the smallest representable amount. Equivalent to Double.MIN_VALUE.

See Also:

Constant Field Values

EXCLUSIVE_ONE

static final double EXCLUSIVE_ONE

A double that is less than 1.0 by the smallest representable amount. Equivalent to 0.9999999999999999.

See Also:

Constant Field Values

Method Detail

nextDouble

double nextDouble(IRNG rng)

Gets a double between getLowerBound() and getUpperBound() that obeys this distribution.

Parameters:

rng - an IRNG, such as RNG or GWTRNG, that this will get one or more random numbers from

Returns:

a double within the range of getLowerBound() and getUpperBound(), both inclusive

getLowerBound

double getLowerBound()

Gets the lower inclusive bound of the distribution. If the bound is exclusive above 0.0, then this will be EXCLUSIVE_ZERO.

Returns:

the lower inclusive bound of the distribution

getUpperBound

double getUpperBound()

Gets the upper inclusive bound of the distribution. If the bound is exclusive below 1.0, like IRNG.nextDouble()), then this will be EXCLUSIVE_ONE.

Returns:

the upper inclusive bound of the distribution

getMean

double getMean()

Gets the mean value of this distribution.

Returns:

the mean value of this distribution