GeometricSampler (Apache Commons RNG Sampling 1.6 API)

java.lang.Object
- org.apache.commons.rng.sampling.distribution.GeometricSampler

```
public final class GeometricSampler
extends Object
```
Sampling from a geometric distribution.
This distribution samples the number of failures before the first success taking values in the set [0, 1, 2, ...].

The sample is computed using a related exponential distribution. If \( X \) is an exponentially distributed random variable with parameter \( \lambda \), then \( Y = \left \lfloor X \right \rfloor \) is a geometrically distributed random variable with parameter \( p = 1 − e^\lambda \), with \( p \) the probability of success.

This sampler outperforms using the InverseTransformDiscreteSampler with an appropriate geometric inverse cumulative probability function.

Usage note: As the probability of success (\( p \)) tends towards zero the mean of the distribution (\( \frac{1-p}{p} \)) tends towards infinity and due to the use of int for the sample this can result in truncation of the distribution.

Sampling uses UniformRandomProvider.nextDouble().

Since:

1.3

See Also:

Geometric distribution - related distributions

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static SharedStateDiscreteSampler`	`of(UniformRandomProvider rng, double probabilityOfSuccess)`	Creates a new geometric distribution sampler.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - of
```
public static SharedStateDiscreteSampler of(UniformRandomProvider rng,
                                            double probabilityOfSuccess)
```
    Creates a new geometric distribution sampler. The samples will be provided in the set k=[0, 1, 2, ...] where k indicates the number of failures before the first success.
    
    Parameters:
    
    rng - Generator of uniformly distributed random numbers.
    
    probabilityOfSuccess - The probability of success.
    
    Returns:
    
    the sampler
    
    Throws:
    
    IllegalArgumentException - if probabilityOfSuccess is not in the range [0 < probabilityOfSuccess <= 1])