This is a problem that a customer of mine just ran into where there
classifier training got hung up.  It isn't really an ubuntu
specific problem, but instead is a problem with uncommons math.  It doesn't
seem possible to specify a seeding strategy
that depends on /dev/urandom which is kind of heinous.  This should happen
in a test, however, because we should be
providing an explicit seed.  It is definitely a production problem.

On Fri, Sep 3, 2010 at 6:30 AM, Drew Farris <[email protected]> wrote:

> I ran into a problems with the first test executed, NormalTest in
> math, hanging on ubuntu 10.04 because /dev/random doesn't contain
> enough entropy. The test blocks for a very very long time trying to
> read from from /dev/random. On my local machine I let it go for
> minutes before killing it. Moving /dev/random and setting up a link to
> /dev/urandom (the non blocking rng) from /dev/random worked. I suspect
> this is an ubuntu specific problem, I've run into the issue before but
> not to this degree.
>
>   java.lang.Thread.State: RUNNABLE
>        at java.io.FileInputStream.readBytes(Native Method)
>        at java.io.FileInputStream.read(FileInputStream.java:199)
>        at
> org.uncommons.maths.random.DevRandomSeedGenerator.generateSeed(DevRandomSeedGenerator.java:49)
>        at
> org.uncommons.maths.random.DefaultSeedGenerator.generateSeed(DefaultSeedGenerator.java:71)
>        at
> org.uncommons.maths.random.MersenneTwisterRNG.<init>(MersenneTwisterRNG.java:74)
>        at
> org.apache.mahout.common.RandomWrapper.buildRandom(RandomWrapper.java:53)
>        at
> org.apache.mahout.common.RandomWrapper.<init>(RandomWrapper.java:37)
>        at
> org.apache.mahout.common.RandomUtils.getRandom(RandomUtils.java:55)
>        at
> org.apache.mahout.math.jet.random.NormalTest.consistency(NormalTest.java:51)
>        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>
> It appears that the hudson build gets stuck for a bit in the same place:
> (from :https://hudson.apache.org/hudson/job/Mahout-Quality/237/console)
>
> Running org.apache.mahout.math.jet.random.NormalTest
> Tests run: 4, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 165.554 sec
>
> I'm also running into issues with o.a.m.df.data.DataTest and
> o.a.m.cf.taste.hadoop.similarity.item.ItemSimilarityTest. Looks like
> DataTest needs @Test annotations and ItemSimilarityTest has a @Test
> annotation on a method that isn't a unit test. I've fixed these and
> can commit if you're ok with that.
>

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