org.das2.qds.math

Class PoissonDistribution

java.lang.Object

org.das2.qds.math.PoissonDistribution

public class PoissonDistribution
extends java.lang.Object

PoissonDistribution generates numbers from the Poisson distribution. Adapted from stocc.cpp. 2018-08-28. Made thread safe, use in Jython scripts will be broken.

Constructor Summary

Constructors

Constructor and Description
PoissonDistribution()

Method Summary

Modifier and Type	Method and Description
int	poisson(double L, java.util.Random random) This function generates a random variate with the Poisson distribution.

Methods inherited from class java.lang.Object

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

Constructor Detail

PoissonDistribution

public PoissonDistribution()

Method Detail

poisson

public int poisson(double L,
                   java.util.Random random)

This function generates a random variate with the Poisson distribution. Uses inversion by chop-down method for L < 17, and ratio-of-uniforms method for L >= 17. For L < 1.E-6 numerical inaccuracy is avoided by direct calculation. For L > 2E9 too big--throws IllegalArgumentException Note this was a static method before 2018-08-28 (v2018a_8), so Jython calls should be PoissonDistribution().poisson().

Parameters:

L - the real value

random - a random number source

Returns:

the integer value.