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+--- Thread: (49G) Wichmann Hill (2005) Random Sequence Generator (/thread-4365.html)
(49G) Wichmann Hill (2005) Random Sequence Generator - Gerald H - 07-15-2015 03:03 PM
Wichmann & Hill's algorithm produces a sequence of randomly distributed reals in the range zero to one.
I dispense with the traditional "pseudo" in my description as the term now merely means "algorithmically produced".
For information concerning the algorithm see:
http://www.eurometros.org/file_download.php?file_key=247
SETWH sets the parameters s1 to s4 for no input.
NEXTR takes no input & returns the next random real to the stack.
Code:
SETWH
::
CK0
BINT5
ONE_DO
%RAN
% 2147483017.
%*
%IP
FPTR2 ^R>Z
"s"
INDEX@
#>$
&$
$>ID
STO
LOOP
;
NEXTR
::
CK0
ZINT 2147483579
ID s1
ZINT 11600
FPTR2 ^RMULText
OVER
FPTR2 ^ZMod
DUP'
ID s1
STO
FPTR2 ^Z>R
SWAP
FPTR2 ^Z>R
%/
ZINT 2147483543
ID s2
ZINT 47003
FPTR2 ^RMULText
OVER
FPTR2 ^ZMod
DUP'
ID s2
STO
FPTR2 ^Z>R
SWAP
FPTR2 ^Z>R
%/
ZINT 2147483423
ID s3
ZINT 23000
FPTR2 ^RMULText
OVER
FPTR2 ^ZMod
DUP'
ID s3
STO
FPTR2 ^Z>R
SWAP
FPTR2 ^Z>R
%/
ZINT 2147483123
ID s4
ZINT 33000
FPTR2 ^RMULText
OVER
FPTR2 ^ZMod
DUP'
ID s4
STO
FPTR2 ^Z>R
SWAP
FPTR2 ^Z>R
%/
%+
%+
%+
%FP
;