gamma ( x -- y )

Vocabulary

math.analysis

Inputs

x

a number

Outputs

y

a number

Word description

Gamma function; an extension of factorial to real and complex numbers.

Definition

USING: combinators.short-circuit kernel math
math.analysis.private ;

IN: math.analysis

: gamma ( x -- y )
    dup { [ 0.0 <= ] [ 1.0 mod zero? ] } 1&&
    [ drop 1/0. ] [
        [ abs gamma-lanczos6 ] keep dup 0 >
        [ drop ] [ gamma-neg ] if
    ] if ;