On Jul 18, 12:24 pm, Clement Pernet <[EMAIL PROTECTED]> wrote: Hi Clement,
> I am looking into it. Thanks. We are still not 100% certain that the probabilistic charpoly mod p is at fault here, but it can't hurt to take a look. > Applying the patch > athttp://sage.math.washington.edu/home/pernet/Patches/charpoly_LUK.patch > > will disable the current probablistic charpoly algorithm. > This could help diagnose the origin of the bug. I have applied the patch and rebuild LinBox and started running the test 500 times to see. Can you guess if/how much this patch does affect performance for charpoly mod p? Some data points: I could never get valgrind to detect any problem with ssmod.py, but since it took about 2200 seconds in sage.math for one round that is not so surprising since the sample set was so small. > Cheers > > Clement Cheers, Michael > > mabshoff a écrit : > > > > > On Jul 17, 10:34 pm, mabshoff <[EMAIL PROTECTED]> wrote: > >> Ok, here is what I found out last night: > > >> * 3.0.3 runs the test 200 times without failing it once > >> * 3.0.4 with the new FLINT 1.0.13 fails 8 ought of 500 tests. > > >> So we are given a couple possibilities: > > >> * There is an algorithmic issue in ssmod somewhere or some > >> algorithmic issue got exposed somehow in 3.0.4+ > >> * There is an undiscovered bug in LinBox > >> * There is an undiscovered bug in FLINT > >> * none of the above > >> * all of the above > > > After looking at the code William has conjectured that it is very > > likely charpoly mod p that fails here. We update Linbox in 3.0.3- > >> 3.0.4, so that fits the bill. This issue is now #3671. To debug this > > we can compute the charpoly with LinBox and the generic code for a > > large number of random inputs and compare. According to William the > > speed difference between generic code and LinBox for the example in > > ssmod (32 by 32 matrices) won't be too large. > > > If you have any (alternate) theories what goes wrong here please let > > us know. > > >> Cheers, > > >> Michael > > > Cheers, > > > Michae --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
