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rpt.remlLMM(y, groups) causes R to crash

On 14-06-06 12:28 PM, AvianResearchDivision wrote:
I don't think you've actually solved your problem this way, but you
have demonstrated that it's something having to do with a
computationally intensive workload, and not something intrinsic about
the code. That is, there's not something about running a single
bootstrap or permutation that will make your computer crash.  (The other
thing to try is using small values of nboot/npermut, but re-running the
command many times to see if you can trigger a crash.) On the other
hand, computer-crashing bugs are usually *not* deterministic in this way
-- they often depend on some haphazard or not-easily-repeatable sequence
of interactions with the operating system ...)

   My more basic question is whether you can make R crash by using the
examples with large values of nboot/npermut (in which case this is a
general issue) or not (in which case it seems like an interaction
between some quirk of your data and the software).  I haven't looked
into what npermut/nboot are doing, but they're presuming computing some
sort of simulation-based p-values/confidence intervals; if you only run
a small number of replicates, then your estimates will be very coarse.
I'm guessing that the small values of nboot/npermut in the examples are
there so that people aren't accidentally running long/slow jobs when
they try out the examples, not that these values are really recommended
for production use. It *might* be possible to get the same answers by
running a large number of commands that each run a small number of
permutation/bootstrap samples and then assembling them, but that's
likely to be tricky.

  Do you have the same kinds of problems if you run from a batch file
rather than from the Windows GUI?

  I *was* going to say that we do know of a few memory-access issues
with lme4, but now that I remember that rpt.remlLMM uses lme and not
lmer, I can't see why that would matter ...

  cheers
    Ben Bolker