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From "Gilles (JIRA)" <j...@apache.org>
Subject [jira] [Created] (MATH-1314) RNG: Warn users about "seeding"
Date Sun, 10 Jan 2016 16:25:40 GMT
Gilles created MATH-1314:
----------------------------

             Summary: RNG: Warn users about "seeding"
                 Key: MATH-1314
                 URL: https://issues.apache.org/jira/browse/MATH-1314
             Project: Commons Math
          Issue Type: Wish
            Reporter: Gilles
             Fix For: 4.0


The "package-info.java" file of {{o.a.c.m.random}} does not mention the problem of seeding.
Many users of CM could not be aware that it is not sufficient to "randomly" choose a seed
in order to ensure a random sequence.
I think that this is what is illustrated by random failures of some unit tests (when the seed
is "randomly" selected).

Do the intricate initialization procedures provided in some implementations (WELL family and
ISAAC) ensure that all seeds are good enough?
Should we provide some tool to test a seed?

By the way, the WELL performances listed on [this table|http://commons.apache.org/proper/commons-math/javadocs/api-3.6/org/apache/commons/math3/random/package-summary.html]
do not correspond to the results obtained on my machine with our {{PerfTestUtils}} benchmark:
the {{MersenneTwister}} is invariably faster than all WELL implementations.



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