public class ZipfDistributionImpl extends AbstractIntegerDistribution implements ZipfDistribution, Serializable
ZipfDistribution
.randomData
Constructor and Description |
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ZipfDistributionImpl(int numberOfElements,
double exponent)
Create a new Zipf distribution with the given number of elements and
exponent.
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Modifier and Type | Method and Description |
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double |
cumulativeProbability(int x)
The probability distribution function P(X <= x) for a Zipf distribution.
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protected int |
getDomainLowerBound(double p)
Access the domain value lower bound, based on
p , used to
bracket a PDF root. |
protected int |
getDomainUpperBound(double p)
Access the domain value upper bound, based on
p , used to
bracket a PDF root. |
double |
getExponent()
Get the exponent characterising the distribution.
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int |
getNumberOfElements()
Get the number of elements (e.g.
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protected double |
getNumericalMean()
Returns the mean.
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protected double |
getNumericalVariance()
Returns the variance.
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int |
getSupportLowerBound()
Returns the lower bound of the support for the distribution.
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int |
getSupportUpperBound()
Returns the upper bound of the support for the distribution.
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double |
probability(int x)
The probability mass function P(X = x) for a Zipf distribution.
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void |
setExponent(double s)
Deprecated.
as of 2.1 (class will become immutable in 3.0)
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void |
setNumberOfElements(int n)
Deprecated.
as of 2.1 (class will become immutable in 3.0)
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cumulativeProbability, cumulativeProbability, cumulativeProbability, inverseCumulativeProbability, isSupportLowerBoundInclusive, isSupportUpperBoundInclusive, probability, reseedRandomGenerator, sample, sample
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
cumulativeProbability, inverseCumulativeProbability
probability
cumulativeProbability, cumulativeProbability
public ZipfDistributionImpl(int numberOfElements, double exponent) throws IllegalArgumentException
IllegalArgumentException
is thrown.numberOfElements
- the number of elementsexponent
- the exponentIllegalArgumentException
- if n ≤ 0 or s ≤ 0.0public int getNumberOfElements()
getNumberOfElements
in interface ZipfDistribution
@Deprecated public void setNumberOfElements(int n)
IllegalArgumentException
is thrown.setNumberOfElements
in interface ZipfDistribution
n
- the number of elementsIllegalArgumentException
- if n ≤ 0public double getExponent()
getExponent
in interface ZipfDistribution
@Deprecated public void setExponent(double s)
IllegalArgumentException
is thrown.setExponent
in interface ZipfDistribution
s
- the exponentIllegalArgumentException
- if s ≤ 0.0public double probability(int x)
probability
in interface IntegerDistribution
x
- the value at which the probability density function is evaluated.public double cumulativeProbability(int x)
cumulativeProbability
in interface IntegerDistribution
cumulativeProbability
in class AbstractIntegerDistribution
x
- the value at which the PDF is evaluated.protected int getDomainLowerBound(double p)
p
, used to
bracket a PDF root.getDomainLowerBound
in class AbstractIntegerDistribution
p
- the desired probability for the critical valuep
protected int getDomainUpperBound(double p)
p
, used to
bracket a PDF root.getDomainUpperBound
in class AbstractIntegerDistribution
p
- the desired probability for the critical valuep
public int getSupportLowerBound()
public int getSupportUpperBound()
protected double getNumericalMean()
Hs1 / Hs
where
Hs1 = generalizedHarmonic(N, s - 1)
Hs = generalizedHarmonic(N, s)
protected double getNumericalVariance()
(Hs2 / Hs) - (Hs1^2 / Hs^2)
where
Hs2 = generalizedHarmonic(N, s - 2)
Hs1 = generalizedHarmonic(N, s - 1)
Hs = generalizedHarmonic(N, s)
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