von-mises-random-float ( mu kappa -- n )

Vocabulary

random

Inputs

mu	an object
kappa	an object

Outputs

n

an object

Definition

USING: combinators.short-circuit kernel math math.constants
math.functions namespaces random.private ;

IN: random

:: von-mises-random-float ( mu kappa -- n )
    random-generator get :> rnd kappa 0.000001 <=
    [ 2pi rnd (random-unit) * ] [
        4.0 kappa sq * 1.0 + sqrt 1.0 + :> a a 2.0 a * sqrt -
        2.0 kappa * / :> b b sq 1.0 + 2.0 b * /
        :> r 0 :> c! 0 :> _f! [
            rnd (random-unit)
            { [ 2.0 c - c * < ] [ 1.0 c - e^ c * <= ] } 1|| not
        ] [
            rnd (random-unit) pi * cos :> z r z * 1.0 + r z + /
            _f! r _f - kappa * c!
        ] do while mu 2pi mod _f cos rnd (random-unit) 0.5 >
        [ + ] [ - ] if
    ] if ;