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https://issues.apache.org/jira/browse/MATH-1154?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14161963#comment-14161963
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Gilles commented on MATH-1154:
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bq. why do you constantly ignore me, and oppose everything I do or say?
Aren't you reversing the situation?
Apart from your patch with "null" RNGs, the other considerations (about
MATH-1224, about improving WellXXX RNGs) are related neither to the issue nor
to the feature proposed to solve it.
It is (IMHO) clearer to separate concerns:
# Is the lazily initialized RNG a useful feature? \[Should be another issue
(feature request).\]
# Is this issue (about tests) to be solved by initializing the RNG with "null"?
\[A possible fix for this issue.\]
# Is the default RNG (in a distribution instance) going to be a
lazily-initialized RNG implementation? \[Another possible fix for this issue
(if and once the feature exists in CM).\]
# Is the default concrete RNG instance to be changed (from WellXxx to ...)?
\[Unrelated.\]
# Is the implementation of WellXxx to be improved? \[Not directly related.\]
# Is the implementation of other RNG (which use insecure constructs) to be
improved? \[My addition of yet another similarly unrelated issue.\]
I'm proposing to tidy up things and process them in order, and you keep
ignoring the suggestion.
If you and the OP want to resolve _this_ issue, then there is only one
alternative at present: Your fix. Please apply it and let's move on to the
other suggestions.
> Statistical tests in stat.inference package are very slow due to implicit
> RandomGenerator initialization
> --------------------------------------------------------------------------------------------------------
>
> Key: MATH-1154
> URL: https://issues.apache.org/jira/browse/MATH-1154
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 3.3
> Reporter: Otmar Ertl
> Attachments: MATH-1154.patch, math3.patch
>
>
> Some statistical tests defined in the stat.inference package (e.g.
> BinomialTest or ChiSquareTest) are unnecessarily very slow (up to a factor 20
> slower than necessary). The reason is the implicit slow initialization of a
> default (Well19937c) random generator instance each time a test is performed.
> The affected tests create some distribution instance in order to use some
> methods defined therein. However, they do not use any method for random
> generation. Nevertheless a random number generator instance is automatically
> created when creating a distribution instance, which is the reason for the
> serious slowdown. The problem is related to MATH-1124.
> There are following solutions:
> 1) Fix the affected statistical tests by passing a light-weight
> RandomGenerator implementation (or even null) to the constructor of the
> distribution.
> 2) Or use for all distributions a RandomGenerator implementation that uses
> lazy initialization to generate the Well19937c instance as late as possible.
> This would also solve MATH-1124.
> I will attach a patch proposal together with a performance test, that will
> demonstrate the speed up after a fix.
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