Package org.bitbrawl.foodfight.util

Class RandomScalar

java.lang.Object

org.bitbrawl.foodfight.util.RandomScalar

All Implemented Interfaces:

DoubleSupplier

@ThreadSafe
public final class RandomScalar
extends Object
implements DoubleSupplier

A random variable used to add a bit of randomness to various parts of the game. This continuous random variable has two positive parameters μ and σ, returned by getMu() and getSigma(). The distribution of these random variables is close to that of a normal distribution, with a mean of μ and a standard deviation of σ, but modified a bit to ensure that values will never be negative. The true value, if Z is a standard normal random variable, is μ × e^{Z × σ / μ}. Note that the median value of a random scalar is exactly μ, while the mean or expected value is a bit higher.

Author:

Finn

Constructor Summary

Constructors

Constructor	Description
RandomScalar(double mu, double sigma)	Creates a random scalar with the given μ and σ.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)
double	getAsDouble()	Generates a value from the continuous distribution represented by this random scalar.
double	getMu()	Returns the μ value for this random scalar.
double	getSigma()	Returns the σ value for this random scalar.
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

RandomScalar

public RandomScalar(double mu,
                    double sigma)

Creates a random scalar with the given μ and σ.

Parameters:

mu - the μ value for the random scalar

sigma - the σ value for the random scalar

Throws:

IllegalArgumentException - if mu or sigma is not finite and positive

Method Detail

getMu

public double getMu()

Returns the μ value for this random scalar.

Returns:

this random scalar's μ value

getSigma

public double getSigma()

Returns the σ value for this random scalar.

Returns:

this random scalar's σ value

getAsDouble

public double getAsDouble()

Generates a value from the continuous distribution represented by this random scalar. Note that this method will return different values when called multiple times.

Specified by:

getAsDouble in interface DoubleSupplier

Returns:

a value from this distribution

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object