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
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