I think we'd be fine dropping zn_poly even if it is 2 or 3 times faster. On Thu, Nov 11, 2021 at 7:18 PM Alex J Best <alex.j.b...@gmail.com> wrote: > > Right, that seems like a fair benchmark to me, does zn_poly (falling back to > ntl) run faster than the force ntl = 1 version in enough ranges of variables > to justify its continued existence? > Knowing whether it failed and fell back (and hence was slower) or just is > simply slower doesn't seem to matter compared to the end result, knowing > where its slower. > > Yes exactly, I forgot now why we decided to use force ntl=1 for cyclic > covers, and indeed I forgot that we did force it completely, I really have no > idea the reasons that went into that decision anymore unfortunately. > > On Tuesday, November 9, 2021 at 10:09:38 PM UTC+1 Michael Orlitzky wrote: >> >> On Tue, 2021-11-09 at 10:54 -0800, Alex J Best wrote: >> > I agree the situation with zn_poly is a mess, but I think it would be good >> > to do some actual benchmarks to check if the NTL code is faster or >> > comparable to the zn_poly version, I don't see any data in the ticket but >> > you do say "The one thing it does is done better by NTL" so maybe you >> > already did some? >> >> It would be hard to benchmark without knowing where zn_poly fails. The >> only function in sagelib that uses zn_poly is in hypellfrob.cpp, and it >> has a comment at the top: >> >> Note that the zn_poly version occasionally fails; this happens more >> frequently for smaller p, but is extremely rare for larger p. This >> wrapper detects this and falls back on the zz_p/ZZ_p versions, which >> should never fail. >> >> That's what I meant by "NTL does it better," and any benchmark would >> have to take into consideration the attempts that failed and were >> actually made with NTL instead. Certainly those cases are slower than >> if we'd just used NTL the first time. >> >> > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/7062f8ee-226c-41d6-ab95-ad0b0094d908n%40googlegroups.com.
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