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{{alias}}( x, α, β )
Evaluates the probability density function (PDF) for a gamma distribution
with shape parameter `α` and rate parameter `β` at a value `x`.
If `α < 0` or `β <= 0`, the function returns `NaN`.
If provided `NaN` as any argument, the function returns `NaN`.
Parameters
----------
x: number
Input value.
α: number
Shape parameter.
β: number
Rate parameter.
Returns
-------
out: number
Evaluated PDF.
Examples
--------
> var y = {{alias}}( 2.0, 0.5, 1.0 )
~0.054
> y = {{alias}}( 0.1, 1.0, 1.0 )
~0.905
> y = {{alias}}( -1.0, 4.0, 2.0 )
0.0
> y = {{alias}}( NaN, 0.6, 1.0 )
NaN
> y = {{alias}}( 0.0, NaN, 1.0 )
NaN
> y = {{alias}}( 0.0, 1.0, NaN )
NaN
// Negative shape parameter:
> y = {{alias}}( 2.0, -1.0, 1.0 )
NaN
// Non-positive rate parameter:
> y = {{alias}}( 2.0, 1.0, -1.0 )
NaN
// Degenerate distribution centered at `0.0` when `α = 0.0`:
> y = {{alias}}( 2.0, 0.0, 2.0 )
0.0
> y = {{alias}}( 0.0, 0.0, 2.0 )
Infinity
{{alias}}.factory( α, β )
Returns a function for evaluating the probability density function (PDF) of
a gamma distribution with shape parameter `α` and rate parameter `β`.
Parameters
----------
α: number
Shape parameter.
β: number
Rate parameter.
Returns
-------
pdf: Function
Probability density function (PDF).
Examples
--------
> var myPDF = {{alias}}.factory( 6.0, 7.0 );
> var y = myPDF( 2.0 )
~0.026
See Also
--------
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