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@stdlib/stats

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Standard library statistical functions.

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{{alias}}( x, a, b, c ) Evaluates the natural logarithm of the probability density function (PDF) for a triangular distribution with minimum support `a`, maximum support `b`, and mode `c` at a value `x`. If the condition `a <= c <= b` is not satisfied, the function returns `NaN`. If either `a`, `b`, or `c` is `NaN`, the function returns `NaN`. Parameters ---------- x: number Input value. a: number Minimum support. b: number Maximum support. c: number Mode. Returns ------- out: number Evaluated logPDF. Examples -------- > var y = {{alias}}( 0.5, -1.0, 1.0, 0.0 ) ~-0.693 > y = {{alias}}( 0.5, -1.0, 1.0, 0.5 ) 0.0 > y = {{alias}}( -10.0, -20.0, 0.0, -2.0 ) ~-2.89 > y = {{alias}}( -2.0, -1.0, 1.0, 0.0 ) -Infinity > y = {{alias}}( NaN, 0.0, 1.0, 0.5 ) NaN > y = {{alias}}( 0.0, NaN, 1.0, 0.5 ) NaN > y = {{alias}}( 0.0, 0.0, NaN, 0.5 ) NaN > y = {{alias}}( 2.0, 1.0, 0.0, NaN ) NaN > y = {{alias}}( 2.0, 1.0, 0.0, 1.5 ) NaN {{alias}}.factory( a, b, c ) Returns a function for evaluating the natural logarithm of the probability density function (PDF) of a triangular distribution with minimum support `a`, maximum support `b`, and mode `c`. Parameters ---------- a: number Minimum support. b: number Maximum support. c: number Mode. Returns ------- logpdf: Function Logarithm of probability density function (PDF). Examples -------- > var mylogpdf = {{alias}}.factory( 0.0, 10.0, 5.0 ); > var y = mylogpdf( 2.0 ) ~-2.526 > y = mylogpdf( 12.0 ) -Infinity See Also --------