@stdlib/stats
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Standard library statistical functions.
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{{alias}}( x, k, λ )
Evaluates the cumulative distribution function (CDF) for an Erlang
distribution with shape parameter `k` and rate parameter `λ` at a value
`x`.
If provided `NaN` as any argument, the function returns `NaN`.
If not provided a nonnegative integer for `k`, the function returns `NaN`.
If provided a non-positive value for `λ`, the function returns `NaN`.
Parameters
----------
x: number
Input value.
k: number
Shape parameter.
λ: number
Rate parameter.
Returns
-------
out: number
Evaluated CDF.
Examples
--------
> var y = {{alias}}( 2.0, 1, 1.0 )
~0.865
> y = {{alias}}( 2.0, 3, 1.0 )
~0.323
> y = {{alias}}( 2.0, 2.5, 1.0 )
NaN
> y = {{alias}}( -1.0, 2, 2.0 )
0.0
> y = {{alias}}( {{alias:/constants/float64/pinf}}, 4, 2.0 )
1.0
> y = {{alias}}( {{alias:/constants/float64/ninf}}, 4, 2.0 )
0.0
> y = {{alias}}( NaN, 0, 1.0 )
NaN
> y = {{alias}}( 0.0, NaN, 1.0 )
NaN
> y = {{alias}}( 0.0, 0, NaN )
NaN
> y = {{alias}}( 2.0, -1, 1.0 )
NaN
> y = {{alias}}( 2.0, 1, -1.0 )
NaN
{{alias}}.factory( k, λ )
Returns a function for evaluating the cumulative distribution function (CDF)
of an Erlang distribution with shape parameter `k` and rate parameter `λ`.
Parameters
----------
k: number
Shape parameter.
λ: number
Rate parameter.
Returns
-------
cdf: Function
Cumulative distribution function (CDF).
Examples
--------
> var mycdf = {{alias}}.factory( 2, 0.5 );
> var y = mycdf( 6.0 )
~0.801
> y = mycdf( 2.0 )
~0.264
See Also
--------