On Nov 27, 2:15 pm, KvS <keesvansch...@gmail.com> wrote: > Dear all, > > just a quick question/remark, today I was working (plotting etc.) with > some quantities that involve (upper) incomplete gamma functions. Some > operations took very long, as it turned out due to the incomplete > gamma function evaluating very slowly for small arguments. Some > testing showed that mpmath's version is a lot quicker (I've seen > differences like 2~3 secs versus ~0.1 secs). Unfortunately I don't > have SAGE on this computer so I can't post any code or exact numbers. > Due to my setup (actually requiring SAGE function objects) I had to > fiddle around and make several changes at several places to be able to > use mpmath's version. I was wondering whether it might be possible & > would be an attractive feature to modify SAGE's version in such a way > that mpmath's version gets called when the function is called with a > numerical argument? > > Many thanks, Kees
On my laptop, I get: sage: %timeit mpmath.gammainc(2r, 3.3r) 625 loops, best of 3: 44.8 µs per loop sage: %timeit mpmath.gammainc(2.1r, 3.3r) 625 loops, best of 3: 588 µs per loop sage: %timeit gamma_inc(2r, 3.3r) 625 loops, best of 3: 493 µs per loop sage: %timeit gamma_inc(2.1r, 3.3r) 625 loops, best of 3: 480 µs per loop So the mpmath incomplete gamma function appears slightly slower for non-integer first argument (this is probably something that can be improved in mpmath), and significantly faster for integer first argument. Perhaps this is what you're seeing. The timings could also depend on the types. I guess the Sage code spends some time converting the problem to Pari and back. For example, the following is much slower: sage: %timeit gamma_inc(SR(2), SR(2.3)) 125 loops, best of 3: 1.76 ms per loop There can be a similar overhead when calling mpmath functions with Sage objects as input. Fredrik -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
