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ru.algorithms
- RU.ALGORITHMS ----------------------------------------------------------------
From : Vladimir Kuznetsov 2:5010/126.91 03 Jul 2001 20:22:44
To : Sandro (Vladimir Uryvaev)
Subject : Re: RANDOM, вопрос созрел.
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In a message dated 28 Jun 01 you wrote to All:
Sa> если, например, внутри ГПСЧ стоит 16разрядный SEED, то не позже чем
Sa> после S=2^16 последовательность повторится.
Это верно только для генераторов типа x1 = (a + x0*b)%c
Hо в природе существуют и более другие генераторы. Вот для примера:
----- cut here -----
This random number generator originally appeared in "Toward a Universal
Random Number Generator" by George Marsaglia and Arif Zaman.
Florida State University Report: FSU-SCRI-87-50 (1987)
It was later modified by F. James and published in "A Review of Pseudo-
random Number Generators"
THIS IS THE BEST KNOWN RANDOM NUMBER GENERATOR AVAILABLE.
(However, a newly discovered technique can yield
a period of 10^600. But that is still in the development stage.)
It passes ALL of the tests for random number generators and has a period
of 2^144, is completely portable (gives bit identical results on all
machines with at least 24-bit mantissas in the floating point
representation).
The algorithm is a combination of a Fibonacci sequence (with lags of 97
and 33, and operation "subtraction plus one, modulo one") and an
"arithmetic sequence" (using subtraction).
========================================================================
This C language version was written by Jim Butler, and was based on a
FORTRAN program posted by David LaSalle of Florida State University.
----- and here -----
Так, что для 24 битного числа с легкостью получаются последовательности
с периодом много больше, чем его размер. Вот.
Bye!
Your wicked friend - Mista K.
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