On Wed, Apr 20, 2011 at 3:01 PM, Daniel Fischer <daniel.is.fisc...@googlemail.com> wrote: > I'm sure it's not criterion, because after I've found that NaNs were > introduced to the resamples vectors during sorting (check the entire > vectors for NaNs before and aftersorting, tracing the count; before: 0, > afterwards often quite a number, sometimes close to 10%), the further tests > didn't involve criterion anymore. criterion is simply the most obvious > place to see the NaNs show up (with 5-10% NaNs among the resamples, it > won't take too long to see one pop up). > > It could be a bug in statistics, but I'm pretty sure this one's not due to > statistics either, since fiddling with vector-algorithms made the NaNs > disappear - btw., Bryan, using the heap sort instead of introsort, I > haven't found any NaNs in my tests, so temporarily switching the algorithm > might cure the symptoms.
It's not a statistics bug. I'm reproducing it here using just vector-algorithms. Fill a vector of size N with [N..1], and (intro) sort it, and you get NaNs. But only with -O or above. Without optimization it doesn't happen (and nothing seems to be reading/writing out of bounds, as I compiled vector with UnsafeChecks earlier and it didn't complain). Filling the vector with [1..N] also doesn't trigger the NaNs. [0,0..0] and [0,0..1] trigger it. I don't know what's going on yet. I have trouble believing it's a bug in vector-algorithms code, though, as I don't think I've written any RULEs (just INLINEs), and that's the one thing that comes to mind in library code that could cause a difference between -O0 and -O. So I'd tentatively suggest it's a vector, base or compiler bug. The above testing is on 64-bit windows running a 32-bit copy of GHC, for reference. My ability to investigate this will be a bit limited for the near future. If someone definitively tracks it down to bugs in my code, though, let me know, and I'll try and push a new release up on hackage. -- Dan _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users