|
Colt 1.1.0 | |||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Objectcern.colt.PersistentObject
cern.jet.random.AbstractDistribution
cern.jet.random.AbstractDiscreteDistribution
cern.jet.random.PoissonSlow
Poisson distribution; See the math definition and animated definition.
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: This is a port of RandPoisson used in CLHEP 1.4.0 (C++). CLHEP's implementation, in turn, is based upon "W.H.Press et al., Numerical Recipes in C, Second Edition".
Field Summary | |
protected double |
cached_alxm
|
protected double |
cached_g
|
protected double |
cached_sq
|
protected static double[] |
cof
|
protected double |
mean
|
protected static double |
MEAN_MAX
|
protected static PoissonSlow |
shared
|
protected static double |
SWITCH_MEAN
|
Fields inherited from class cern.jet.random.AbstractDistribution |
randomGenerator |
Fields inherited from class cern.colt.PersistentObject |
serialVersionUID |
Constructor Summary | |
PoissonSlow(double mean,
RandomEngine randomGenerator)
Constructs a poisson distribution. |
Method Summary | |
static double |
logGamma(double xx)
Returns the value ln(Gamma(xx) for xx > 0. |
int |
nextInt()
Returns a random number from the distribution. |
protected int |
nextIntSlow()
Returns a random number from the distribution. |
void |
setMean(double mean)
Sets the mean. |
static int |
staticNextInt(double mean)
Returns a random number from the distribution with the given mean. |
String |
toString()
Returns a String representation of the receiver. |
Methods inherited from class cern.jet.random.AbstractDiscreteDistribution |
nextDouble |
Methods inherited from class cern.jet.random.AbstractDistribution |
apply, apply, clone, getRandomGenerator, makeDefaultGenerator, setRandomGenerator |
Methods inherited from class java.lang.Object |
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
protected double mean
protected double cached_sq
protected double cached_alxm
protected double cached_g
protected static final double MEAN_MAX
protected static final double SWITCH_MEAN
protected static final double[] cof
protected static PoissonSlow shared
Constructor Detail |
public PoissonSlow(double mean, RandomEngine randomGenerator)
Method Detail |
public static double logGamma(double xx)
public int nextInt()
nextInt
in class AbstractDiscreteDistribution
protected int nextIntSlow()
public void setMean(double mean)
public static int staticNextInt(double mean)
public String toString()
|
Colt 1.1.0 | |||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |