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From S├ębastien Brisard <>
Subject [math] Reliability of Well1024a
Date Sat, 31 Dec 2011 14:50:44 GMT
In rev 1226041, I committed a patch proposed by Christian (see
MATH-692). Unfortunately, I didn't notice that this patch causes the
failure of Well1024aTest. Since this morning, I've been looking into
that failure. I don't think that any of Christian's proposed
modifications is to be incriminated. Rather, I'm wondering whether
Well1024a is reliable. Indeed, varying the seed in
Well1024aTest.makeGenerator() causes failure of various unit tests
  - SEED = 100 causes testNextPoissonConsistency() to fail,
  - SEED = 1000 causes testNextIntPositiveRange(),
testNextLongNegativeRange() and testNextLongPositiveRange() to fail,
while *all* tests pass with SEED = 1001. I think this probability of
failure is well above the 0.001 threshold of the chi-square test.

I'm not very familiar with this part of CM, and would very much like
to know what you think.

NOTE: in rev 1226096, I set the SEED to 1001, so as to make Gump stop
complaining. Obivously, this is a very dirty trick.


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