Distributions

java.lang.Object
- de.grogra.blocks.arrangeBlock.Distributions

```
public class Distributions
extends java.lang.Object
```
offers several discrete and continuous distributions all seeded by a common well-spaced pseudo random number generator (PRNG).

Constructor Summary

Constructors
Constructor and Description
`Distributions()` The seed is automatically provided by a well-spaced `SeedGenerator`
`Distributions(ContinuousGenerator gen)` This constructor allows for manually specially the continous generator shared to compute the distribution function.
`Distributions(long seed)` The seed is manually set

Method Summary

Methods
Modifier and Type	Method and Description
`long`	`bernoulli(double prob)` computes a Bernoulli's distribution
`double`	`beta(double shape_a, double shape_b)` computes a beta distribution using Cheng's method (1978) when shape_a>1 or shape_b>1 and Berman's method (1970) otherwise
`double`	`betaprime(double shape_a, double shape_b)` computes a beta prime distribution
`long`	`binomial(double prob, int trials)` computes a binomial distribution
`double`	`cauchy(double median, double scale)` computes a Cauchy's distribution
`double`	`chisquare(long deg_freedom)` computes a chisquare distribution
`double`	`erlang(double scale, double shape)` computes an Erlang's distribution
`double`	`f(long num_deg_freedom, long den_deg_freedom)` computes a F distribution
`double`	`gamma(double scale, double shape)` computes a gamma distribution
`long`	`geometric(double prob)` computes a geometric distribution
`double`	`invgamma(double scale, double shape)` computes an invgamma distribution
`double`	`logistic(double location, double scale)` computes a logistic distribution
`double`	`lognormal(double mean, double variance)` computes a lognormal distribution
`double`	`lognormal2(double mean, double std_dev)` computes a lognormal distribution
`double`	`negexp(double mean)` computes a negexp distribution
`double`	`normal(double mean, double variance)` computes a normal distribution; sample are provided by the same PRGN
`double`	`normal2(double mean, double std_dev)` computes a normal distribution; sample are provided by the same PRGN
`double`	`pareto(double scale, double shape)` computes a pareto distribution; sample is provided by the PRGN
`long`	`pascal(double prob, int successes)` computes a Pascal's distribution
`long`	`poisson(double mean)` computes a poisson distribution
`double`	`tstudent(long deg_freedom)` computes a tstudent distribution; sample is provided by the PRGN
`double`	`uniform(double min, double max)` computes a uniform distribution; sample is provided by the PRGN
`double`	`weibull(double scale, double shape)` computes a weibull distribution; sample is provided by the PRGN

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

- Constructor Detail
  - Distributions
```
public Distributions()
```
    The seed is automatically provided by a well-spaced SeedGenerator
  - Distributions
```
public Distributions(ContinuousGenerator gen)
```
    This constructor allows for manually specially the continous generator shared to compute the distribution function.
  - Distributions
```
public Distributions(long seed)
```
    The seed is manually set
- Method Detail
  - bernoulli
```
public long bernoulli(double prob)
```
    computes a Bernoulli's distribution
    
    Returns:
    1 iif sample ≤ prob, 0 otherwise; sample is provided by the PRGN
  - beta
```
public double beta(double shape_a,
          double shape_b)
```
    computes a beta distribution using Cheng's method (1978) when shape_a>1 or shape_b>1 and Berman's method (1970) otherwise
  - betaprime
```
public double betaprime(double shape_a,
               double shape_b)
```
    computes a beta prime distribution
    
    Returns:
    1/beta(shape_a, shape_b) - 1
  - binomial
```
public long binomial(double prob,
            int trials)
```
    computes a binomial distribution
    
    Returns:
    ∑(i=0; i<trials-1; bernoulli(prob))
  - cauchy
```
public double cauchy(double median,
            double scale)
```
    computes a Cauchy's distribution
    
    Returns:
    median + scale/tan(Π * sample); sample is provided by the PRGN
  - chisquare
```
public double chisquare(long deg_freedom)
```
    computes a chisquare distribution
    
    Returns:
    ∑(i=0; i<deg_freedom; normal(0,1))
  - erlang
```
public double erlang(double scale,
            double shape)
```
    computes an Erlang's distribution
    
    Returns:
    -scale * log ( ∏(i=0; i<shape; sample) ); sample is provided by the PRGN
  - f
```
public double f(long num_deg_freedom,
       long den_deg_freedom)
```
    computes a F distribution
    
    Returns:
    chisquare(num_deg_freedom)/num_deg_freedom / chisquare(den_deg_freedom)/den_deg_freedom
  - gamma
```
public double gamma(double scale,
           double shape)
```
    computes a gamma distribution
  - geometric
```
public long geometric(double prob)
```
    computes a geometric distribution
    
    Returns:
    ⌈ log(sample)/log(1-prob) ⌉; sample is provided by the PRGN
  - invgamma
```
public double invgamma(double scale,
              double shape)
```
    computes an invgamma distribution
    
    Returns:
    1.0/gamma(scale, shape)
  - logistic
```
public double logistic(double location,
              double scale)
```
    computes a logistic distribution
    
    Returns:
    location - scale * log (1/sample - 1)
  - lognormal
```
public double lognormal(double mean,
               double variance)
```
    computes a lognormal distribution
    
    Returns:
    exp(mean + √variance * normal(0,1))
  - lognormal2
```
public double lognormal2(double mean,
                double std_dev)
```
    computes a lognormal distribution
    
    Parameters:
    std_dev - is assumed to be the square root of the variance.
    
    Returns:
    exp(mean + std_dev * normal(0,1))
  - negexp
```
public double negexp(double mean)
```
    computes a negexp distribution
    
    Returns:
    -mean * log (sample); where sample is provided by the PRGN
  - normal
```
public double normal(double mean,
            double variance)
```
    computes a normal distribution; sample are provided by the same PRGN
    
    Returns:
    mean + √(variance) * cos (2Π * sample) * √(-2 * log (sample))
  - normal2
```
public double normal2(double mean,
             double std_dev)
```
    computes a normal distribution; sample are provided by the same PRGN
    
    Parameters:
    std_dev - is assumed to be the square root of the variance.
    
    Returns:
    mean + std_dev * cos (2Π * sample) * √(-2 * log (sample))
  - pareto
```
public double pareto(double scale,
            double shape)
```
    computes a pareto distribution; sample is provided by the PRGN
    
    Returns:
    scale / (sample^(1/shape))
  - pascal
```
public long pascal(double prob,
          int successes)
```
    computes a Pascal's distribution
    
    Returns:
    ∑(i=0; i<successes; geometric(prob))
  - poisson
```
public long poisson(double mean)
```
    computes a poisson distribution
    
    Returns:
    the smallest integer x so as ∏(i=0; i<x; sample) ≤ exp(-mean)
  - tstudent
```
public double tstudent(long deg_freedom)
```
    computes a tstudent distribution; sample is provided by the PRGN
    
    Returns:
    normal(0,1)/√(chisquare(deg_freedom)/deg_freedom)
  - uniform
```
public double uniform(double min,
             double max)
```
    computes a uniform distribution; sample is provided by the PRGN
    
    Returns:
    min + (max-min) * sample
  - weibull
```
public double weibull(double scale,
             double shape)
```
    computes a weibull distribution; sample is provided by the PRGN
    
    Returns:
    scale * (sample ^ (1/shape))

Class Distributions

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Distributions

Distributions

Distributions

Method Detail

bernoulli

beta

betaprime

binomial

cauchy

chisquare

erlang

f

gamma

geometric

invgamma

logistic

lognormal

lognormal2

negexp

normal

normal2

pareto

pascal

poisson

tstudent

uniform

weibull