public class Poisson extends Object implements BinomialLike
p(k) = (mean^k / k!) * exp(-mean) for k >= 0.
Valid parameter ranges: mean > 0. Note: if mean <= 0.0 then always returns zero.
Instance methods operate on a user supplied uniform random number generator; they are unsynchronized.
Implementation: High performance implementation. Patchwork Rejection/Inversion method.
H. Zechner (1994): Efficient sampling from continuous and discrete unimodal distributions, Doctoral Dissertation, 156 pp., Technical University Graz, Austria.
Also see
Stadlober E., H. Zechner (1999), The patchwork rejection method for sampling from unimodal distributions, to appear in ACM Transactions on Modelling and Simulation.
Modifier and Type | Field and Description |
---|---|
protected double |
c_pm |
protected double |
dl |
protected double |
dr |
protected double |
f1 |
protected double |
f2 |
protected double |
f4 |
protected double |
f5 |
protected int |
k1 |
protected int |
k2 |
protected int |
k4 |
protected int |
k5 |
protected double |
l_my |
protected double |
ll |
protected int |
llll |
protected double |
lr |
protected int |
m |
protected static double |
MEAN_MAX |
protected double |
my_last |
protected double |
my_old |
protected double |
p |
protected double |
p0 |
protected double |
p1 |
protected double |
p2 |
protected double |
p3 |
protected double |
p4 |
protected double |
p5 |
protected double |
p6 |
protected double[] |
pp |
protected double |
q |
protected double |
r1 |
protected double |
r2 |
protected double |
r4 |
protected double |
r5 |
protected RandomGenerator |
randomGenerator |
protected static double |
SWITCH_MEAN |
Constructor and Description |
---|
Poisson(RandomGenerator randomGenerator)
Constructs a poisson distribution.
|
Modifier and Type | Method and Description |
---|---|
int |
nextInt(double theMean)
Returns a random number from the distribution; bypasses the internal state.
|
int |
nextInt(int n,
double p) |
protected final RandomGenerator randomGenerator
protected double my_old
protected double p
protected double q
protected double p0
protected double[] pp
protected int llll
protected double my_last
protected double ll
protected int k2
protected int k4
protected int k1
protected int k5
protected double dl
protected double dr
protected double r1
protected double r2
protected double r4
protected double r5
protected double lr
protected double l_my
protected double c_pm
protected double f1
protected double f2
protected double f4
protected double f5
protected double p1
protected double p2
protected double p3
protected double p4
protected double p5
protected double p6
protected int m
protected static final double MEAN_MAX
protected static final double SWITCH_MEAN
public Poisson(RandomGenerator randomGenerator)
public int nextInt(double theMean)
public int nextInt(int n, double p)
nextInt
in interface BinomialLike
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