retroforth/example/rng.retro

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## xoroshiro128**
XOR/rotate/shift/rotate PNRG (See http://xoshiro.di.unimi.it/)
~~~
{{
'JUMP d:create #2271477771 , #4114797267 , #1872770499 , #2012404571 ,
'k var 't var 's0 var 's1 var 's2 var 's3 var
:reseed (n-) dup !s1 dup !s2 dup !s3 dup !k !t ;
:rotl (x-) !k [ @k n:negate shift ] [ #32 @k - shift ] bi or ;
:res** (-n) @s0 #5 * #7 rotl #9 * ;
:next (-)
@s1 dup #-9 shift push @s3 @s0 @s2
\pudupoxo
\pupu....
\pudupoxo
\swposwpo
\dupuxopu
\pudupoxo
\popopoxo
!s2 !s1 !s0 #11 rotl !s3 ;
:xor-er (nananana-nananana)
\dupufexo \pu......
\dupufexo \pu......
\dupufexo \pu......
\dupufexo \pu......
\popopopo \popopopo ;
:jump? (nm-) [ JUMP + fetch ] dip #1 swap n:negate shift and ;
:inner (n-n)
#32 [ dup I jump? [ [ xor-er ] dip ] if next ] times<with-index> ;
---reveal---
:random:xoroshiro128** (-n)
next res** ;
:random:xoroshiro128**:jump (-)
#0 &s3 #0 &s2 #0 &s1 #0 &s0
#4 [ I inner drop ] times<with-index>
\stststst ;
:random:xoroshiro128**:set-seed (n-)
reseed #100 [ next ] times ;
:random:xoroshiro128**:test-seed (nnnn-)
!s0 !s1 !s2 !s3 ;
}}
~~~
## Mersenne Twister
This is adapted from Samuel A. Falvo II's implementation. The
original commentary follows:
As taken from ttp://en.wikipedia.org/wiki/Mersenne_twister
I am aware of Wil Baden's sources, but I had difficulty
getting it to compile under SwiftForth out of the box.
This module exposes the following API:
seeded ( uSeed -- )
Seeds the random number generator with the provided 32-bit,
unsigned value.
probability ( -- u )
Returns a random value that falls in the range [0,
$FFFFFFFF].
All other definitions are safe to shadow/redefine elsewhere.
Copyright (c) 2010, Samuel A. Falvo II
All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, are permitted provided that the following
conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials
provided with the distribution.
* Neither the name of Samuel A. Falvo II, Falvo Technical
Solutions, nor the names of its contributors may be used to
endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.
In adapting this, some concessions were made since RETRO only
has signed 32-bit values.
random:mersenne:set-seed (n-)
Seeds the random number generator with the provided 32-bit,
unsigned value.
random:mersenne (-n)
Returns a random value that falls in the range [0,
n:MAX].
~~~
{{
'States d:create #625 allot
'Index var
:reset (n-)
&States over n:dec + dup fetch #30 shift swap fetch
xor #1812433253 * over + n:MAX and swap &States + store ;
:randomized (-)
#1 [ dup reset n:inc dup #624 gt? ] until drop ;
:y (n-y)
dup n:inc #624 mod &States + fetch n:MAX and
swap &States + fetch #-31 shift + ;
:altered (n-)
dup y dup #1 and #1073741823 *
[ #2 / over #397 + #624 mod &States + fetch xor ] dip
xor swap &States + store ;
:scrambled (-)
#0 [ dup altered n:inc dup #624 gt? ] until drop ;
---reveal---
:random:mersenne:set-seed (n-)
!States #0 !Index randomized ;
:random:mersenne (-n)
@Index n:zero? &scrambled if @Index &States + fetch
dup #11 shift xor dup #-7 shift #1073741823 and xor dup #-15 shift
#2011365376 and xor dup #18 shift xor @Index n:inc #624 mod !Index ;
}}
~~~