# HG changeset patch
# User Claus Gittinger <cg@exept.de>
# Date 1412170045 -7200
# Node ID 9f2ba94535c2f66cc025c75d5f4ef80f03f1201b
# Parent  2df5a041ea672590c455d48e954a268e4d15b7b6
initial checkin

diff -r 2df5a041ea67 -r 9f2ba94535c2 RandomKISS2.st
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/RandomKISS2.st	Wed Oct 01 15:27:25 2014 +0200
@@ -0,0 +1,112 @@
+"{ Package: 'stx:libbasic2' }"
+
+Object subclass:#RandomKISS2
+	instanceVariableNames:'x y z c'
+	classVariableNames:''
+	poolDictionaries:''
+	category:'Magnitude-Numbers'
+!
+
+!RandomKISS2 class methodsFor:'documentation'!
+
+documentation
+"
+    Warning: this generator should not be used for cryptographic work.
+
+    NO WARRANTY
+
+    KISS combines a linear congruence, XorShift and Lag with carry geenrator.
+    The idea is from George Marsaglia.
+    KISS2 uses slightly different parameters and initial state.
+
+    RandomKISS2 new nextInteger
+    (RandomKISS2 new:5489) nextInteger
+
+    If heavily used, it may be useful to embed the original C code as inline C code for a big speedup)
+
+    Please read:
+        http://www.cs.ucl.ac.uk/staff/d.jones/GoodPracticeRNG.pdf
+
+    [see also:]
+        RandomGenerator - the default; uses the machines /dev/random if available
+        Random  - fast, but generates less quality random numbers
+        RandomTT800 - another random generator
+        RandomParkMiller - another random generator
+        RandomMT19937 - another random generator
+
+    [author:]
+        Ported to Smalltalk by Claus Gittinger.
+"
+! !
+
+!RandomKISS2 class methodsFor:'instance creation'!
+
+new
+    ^ self basicNew 
+        initialize;
+        seed:(Time millisecondClockValue)
+!
+
+new:seed
+    ^ self basicNew 
+        initialize;
+        seed:seed
+! !
+
+!RandomKISS2 methodsFor:'initialization'!
+
+initialize
+    x := 123456789. "/ <- any seed !!= 0
+    y := 362436000.
+    z := 521288629.
+    c := 7654321.
+!
+
+seed:seed
+    self assert:(seed ~= 0).
+    x := seed.
+! !
+
+!RandomKISS2 methodsFor:'random numbers'!
+
+nextBoolean
+    "generates the next integer in 0..FFFFFFFF"
+
+    ^ self nextInteger > 16r7FFFFFFF
+!
+
+nextInteger
+    "generates the next integer in 0..FFFFFFFF"
+
+    |t|
+
+    "/ Linear Congruencegenerator
+    x := (314527869 * x) + 1234567.
+    x := x bitAnd:16rFFFFFFFF.
+
+    "/ Xorshift
+    y := y bitXor:(y << 5).
+    y := y bitAnd:16rFFFFFFFF.
+    y := y bitXor:(y >> 7).
+    y := y bitAnd:16rFFFFFFFF.
+    y := y bitXor:(y << 22).
+    y := y bitAnd:16rFFFFFFFF.
+
+    "/ Multiply-with-carry
+    t := (4294584393 * z) + c.
+    c := t >> 32.
+    z := t bitAnd:16rFFFFFFFF.
+
+    ^ (x + y + z) bitAnd:16rFFFFFFFF
+! !
+
+!RandomKISS2 class methodsFor:'documentation'!
+
+version
+    ^ '$Header: /cvs/stx/stx/libbasic2/RandomKISS2.st,v 1.1 2014-10-01 13:27:25 cg Exp $'
+!
+
+version_CVS
+    ^ '$Header: /cvs/stx/stx/libbasic2/RandomKISS2.st,v 1.1 2014-10-01 13:27:25 cg Exp $'
+! !
+