lagged-fibonacci

Vocabulary

random.lagged-fibonacci

Definition

USING: math specialized-arrays.instances.alien.c-types.double ;

IN: random.lagged-fibonacci

TUPLE: lagged-fibonacci
    { u double-array initial: double-array{ } }
    { pt0 fixnum initial: 0 } { pt1 fixnum initial: 0 } ;

Methods

USING: accessors kernel math random.lagged-fibonacci
random.lagged-fibonacci.private sequences.private ;

M:: lagged-fibonacci random-float* ( lagged-fibonacci -- n )
    lagged-fibonacci [ pt0>> ] [ u>> ] bi nth-unsafe
    lagged-fibonacci [ pt1>> ] [ u>> ] bi nth-unsafe - dup 0.0 <
    [ 1.0 + ] when [
        lagged-fibonacci [ pt0>> ] [ u>> ] bi set-nth-unsafe
        lagged-fibonacci [ adjust-ptr ] change-pt0 drop
        lagged-fibonacci [ adjust-ptr ] change-pt1 drop
    ] keep ; inline


USING: accessors kernel math random random.lagged-fibonacci
random.lagged-fibonacci.private sequences ;

M:: lagged-fibonacci seed-random
    ( lagged-fibonacci seed -- rnd )
    seed normalize-seed seed! seed 30082 /i
    :> ij seed 30082 ij * - :> kl ij 177 /i 177 mod 2 +
    :> i! ij 177 mod 2 + :> j! kl 169 /i 178 mod 1 +
    :> k! kl 169 mod :> l! lagged-fibonacci u>> [
        drop
        0.0 :> s! 0.5 :> t! 0.0 :> m! lagged-fibonacci-sig-bits 
        [
            i j * 179 mod k * 179 mod m! j i! k j! m k! 53 l *
            1 + 169 mod l! l m * 64 mod 31 > [ s t + s! ] when
            t 0.5 * t!
        ] times s
    ] map! drop lagged-fibonacci p-r >>pt0 q-r >>pt1 ; inline