@stdlib/stats
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Standard library statistical functions.
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{{alias}}( p, α, β )
Evaluates the quantile function for a gamma distribution with shape
parameter `α` and rate parameter `β` at a probability `p`.
If `p < 0` or `p > 1`, the function returns `NaN`.
If `α < 0` or `β <= 0`, the function returns `NaN`.
If provided `NaN` as any argument, the function returns `NaN`.
Parameters
----------
p: number
Input probability.
α: number
Shape parameter.
β: number
Rate parameter.
Returns
-------
out: number
Evaluated quantile function.
Examples
--------
> var y = {{alias}}( 0.8, 2.0, 1.0 )
~2.994
> y = {{alias}}( 0.5, 4.0, 2.0 )
~1.836
> y = {{alias}}( 1.1, 1.0, 1.0 )
NaN
> y = {{alias}}( -0.2, 1.0, 1.0 )
NaN
> y = {{alias}}( NaN, 1.0, 1.0 )
NaN
> y = {{alias}}( 0.0, NaN, 1.0 )
NaN
> y = {{alias}}( 0.0, 1.0, NaN )
NaN
// Non-positive shape parameter:
> y = {{alias}}( 0.5, -1.0, 1.0 )
NaN
// Non-positive rate parameter:
> y = {{alias}}( 0.5, 1.0, -1.0 )
NaN
// Degenerate distribution centered at `0.0` when `α = 0.0`:
> y = {{alias}}( 0.3, 0.0, 2.0 )
0.0
> y = {{alias}}( 0.9, 0.0, 2.0 )
0.0
{{alias}}.factory( α, β )
Returns a function for evaluating the quantile function of a gamma
distribution with shape parameter `α` and rate parameter `β`.
Parameters
----------
α: number
Shape parameter.
β: number
Rate parameter.
Returns
-------
quantile: Function
Quantile function.
Examples
--------
> var myQuantile = {{alias}}.factory( 2.0, 2.0 );
> var y = myQuantile( 0.8 )
~1.497
> y = myQuantile( 0.4 )
~0.688
See Also
--------