gamma ( x -- value )

Vocabulary

picomath

Inputs

x

an object

Outputs

value

an object

Definition

USING: combinators kernel math math.functions picomath.private ;

IN: picomath

:: gamma ( x -- value )
    x 0 <= [ "Invalid input" throw ] when x {
        { [ dup 0.001 < ] [ GAMMA * 1.0 + x * 1.0 swap / ] }
        { [ dup 12.0 < ] [ (gamma) ] }
        { [ dup 171.624 > ] [ drop 1/0. ] }
        [ log-gamma e^ ]
    } cond ;