public class GammaVariate extends RandomVariateBase
Modifier and Type | Field and Description |
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private double |
a
Holds a precalculated value.
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private double |
alpha
The Alpha parameter for this GammaVariate.
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private double |
alphaInv
Holds a precalculated value.
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private double |
b
Holds a precalculated value.
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private double |
beta
The Beta parameter for this GammaVariate.
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private double |
d
Holds a precalculated value.
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private double |
p
Holds a precalculated value.
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private double |
q
Holds a precalculated value.
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private double |
theta
Holds a precalculated value.
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private double |
u1
Holds a precalculated value.
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private double |
v
Holds a precalculated value.
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private double |
w
Holds a precalculated value.
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private double |
z
Holds a precalculated value.
|
rng
Constructor and Description |
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GammaVariate()
Instantiates a new GammaVariate.
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Modifier and Type | Method and Description |
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double |
generate()
Generate a random variate having this class's distribution.
|
double |
getAlpha() |
double |
getBeta() |
java.lang.Object[] |
getParameters()
Returns a two element array containing the alpha and beta.
|
void |
setAlpha(double alpha) |
void |
setBeta(double beta)
Warning: Does not update the pre-calculated
values use setAlpha() to cause recalculation to occur.
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protected void |
setConvenienceParameters()
Pre-calculates values that only depend on alpha and beta.
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void |
setParameters(java.lang.Object... params)
Sets alpha and beta for this GammaVariate.
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java.lang.String |
toString() |
getRandomNumber, setRandomNumber
private double alpha
private double beta
private double b
private double p
private double a
private double q
private double theta
private double d
private double z
private double u1
private double v
private double w
private double alphaInv
public GammaVariate()
public void setParameters(java.lang.Object... params)
params
- elements are (α, β)java.lang.IllegalArgumentException
- If the given array does not contain
exactly two Numbers or if either of the parameters is not positive.public java.lang.Object[] getParameters()
public double generate()
RandomVariate
protected void setConvenienceParameters()
public void setAlpha(double alpha)
alpha
- new value of αjava.lang.IllegalArgumentException
- If alpha ≤ 0.0.public void setBeta(double beta)
beta
- the value of βjava.lang.IllegalArgumentException
- If beta is not positive.public double getAlpha()
public double getBeta()
public java.lang.String toString()
toString
in class java.lang.Object