Package cern.jet.random
Class Exponential
- java.lang.Object
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- cern.colt.PersistentObject
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- cern.jet.random.AbstractDistribution
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- cern.jet.random.AbstractContinousDistribution
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- cern.jet.random.Exponential
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- All Implemented Interfaces:
DoubleFunction
,IntFunction
,java.io.Serializable
,java.lang.Cloneable
public class Exponential extends AbstractContinousDistribution
Exponential Distribution (aka Negative Exponential Distribution); See the math definition animated definition.p(x) = lambda*exp(-x*lambda) for x >= 0, lambda > 0.
Instance methods operate on a user supplied uniform random number generator; they are unsynchronized.
- Static methods operate on a default uniform random number generator; they are synchronized.
- Version:
- 1.0, 09/24/99
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected double
lambda
protected static Exponential
shared
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Fields inherited from class cern.jet.random.AbstractDistribution
randomGenerator
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Fields inherited from class cern.colt.PersistentObject
serialVersionUID
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Constructor Summary
Constructors Constructor Description Exponential(double lambda, RandomEngine randomGenerator)
Constructs a Negative Exponential distribution.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description double
cdf(double x)
Returns the cumulative distribution function.double
nextDouble()
Returns a random number from the distribution.double
nextDouble(double lambda)
Returns a random number from the distribution; bypasses the internal state.double
pdf(double x)
Returns the probability distribution function.void
setState(double lambda)
Sets the mean.static double
staticNextDouble(double lambda)
Returns a random number from the distribution with the given lambda.java.lang.String
toString()
Returns a String representation of the receiver.private static void
xstaticSetRandomGenerator(RandomEngine randomGenerator)
Sets the uniform random number generated shared by all static methods.-
Methods inherited from class cern.jet.random.AbstractDistribution
apply, apply, clone, getRandomGenerator, makeDefaultGenerator, nextInt, setRandomGenerator
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Field Detail
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lambda
protected double lambda
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shared
protected static Exponential shared
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Constructor Detail
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Exponential
public Exponential(double lambda, RandomEngine randomGenerator)
Constructs a Negative Exponential distribution.
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Method Detail
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cdf
public double cdf(double x)
Returns the cumulative distribution function.
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nextDouble
public double nextDouble()
Returns a random number from the distribution.- Specified by:
nextDouble
in classAbstractDistribution
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nextDouble
public double nextDouble(double lambda)
Returns a random number from the distribution; bypasses the internal state.
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pdf
public double pdf(double x)
Returns the probability distribution function.
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setState
public void setState(double lambda)
Sets the mean.
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staticNextDouble
public static double staticNextDouble(double lambda)
Returns a random number from the distribution with the given lambda.
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toString
public java.lang.String toString()
Returns a String representation of the receiver.- Overrides:
toString
in classjava.lang.Object
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xstaticSetRandomGenerator
private static void xstaticSetRandomGenerator(RandomEngine randomGenerator)
Sets the uniform random number generated shared by all static methods.- Parameters:
randomGenerator
- the new uniform random number generator to be shared.
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