Hi Sebastian, On Tue, 5 Jan 2010 04:10:08 -0800 (PST) Sebastian Pancratz <s...@pancratz.org> wrote:
> Dear all, > > When looking at trac ticket #7730 (which essentially ends with saying > that GCD computations over multivariate polynomial rings are slow), I > noticed that the current implementation of multiplication in fraction > fields computes the product (a/b) * (c/d) by first computing a*c and > b*d, and then dividing out common factors (in the case of exact > underlying rings). > > I am wondering whether there is a good reason for doing this. I believe the reason is that no one implemented anything else. When I read the paragraph above, I couldn't believe we still used naive multiplication, especially since I implemented the Henrici multiplication ages ago. Apparently, I never submitted the patch, waiting to include other improvements with it indefinitely. I found my old patch, which had a modification date of "Wed Apr 09 09:24:45 2008", and rebased it to 4.3. The new version is here: http://sage.math.washington.edu/home/burcin/henrici_mul.patch It probably needs more work to add more doctests, etc. Note that you can also do a similar trick for derivatives. It would be great if you implemented that as well. Can you handle the rest of the submission & review process? I am very busy with thesis related work these days. Thank you. Cheers, Burcin -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
