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random: support "random" on floats (uses uniform-random-float).
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mrjbq7 committed Oct 5, 2012
1 parent f7d58ff commit 9dafa32
Showing 1 changed file with 9 additions and 6 deletions.
15 changes: 9 additions & 6 deletions basis/random/random.factor
@@ -1,11 +1,12 @@
! Copyright (C) 2008 Doug Coleman.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors alien.c-types alien.data arrays assocs
byte-arrays byte-vectors combinators combinators.short-circuit
fry hashtables hashtables.private hints io.backend io.binary
USING: accessors alien.data arrays assocs byte-arrays
byte-vectors combinators combinators.short-circuit fry
hashtables hashtables.private hints io.backend io.binary
kernel locals math math.bitwise math.constants math.functions
math.order math.ranges namespaces sequences sequences.private
sets summary system typed vocabs ;
QUALIFIED-WITH: alien.c-types c
IN: random

SYMBOL: system-random-generator
Expand All @@ -18,10 +19,10 @@ GENERIC: random-bytes* ( n tuple -- byte-array )

M: object random-bytes* ( n tuple -- byte-array )
[ [ <byte-vector> ] keep 4 /mod ] dip
[ pick '[ _ random-32* int <ref> _ push-all ] times ]
[ pick '[ _ random-32* c:int <ref> _ push-all ] times ]
[
over zero?
[ 2drop ] [ random-32* int <ref> swap head append! ] if
[ 2drop ] [ random-32* c:int <ref> swap head append! ] if
] bi-curry bi* B{ } like ;

HINTS: M\ object random-bytes* { fixnum object } ;
Expand Down Expand Up @@ -112,7 +113,7 @@ ERROR: too-many-samples seq n ;
<PRIVATE

: (uniform-random-float) ( min max obj -- n )
[ 4 4 ] dip [ random-bytes* uint deref >float ] curry bi@
[ 4 4 ] dip [ random-bytes* c:uint deref >float ] curry bi@
2.0 32 ^ * +
[ over - 2.0 -64 ^ * ] dip
* + ; inline
Expand All @@ -122,6 +123,8 @@ PRIVATE>
: uniform-random-float ( min max -- n )
random-generator get (uniform-random-float) ; inline

M: float random [ f ] [ 0.0 swap uniform-random-float ] if-zero ;

: random-unit ( -- n )
0.0 1.0 uniform-random-float ; inline

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