On 13 Nov., 22:48, Robert Kern <[EMAIL PROTECTED]> wrote: > Slaunger wrote: > > It is always good to ask yourself a question. > > I had forgooten about the reduce function > > > I guess this implementation > > > from numpy import * > > > def compl_add_uint16(a, b): > > c = a + b > > c += c >> 16 > > return c & 0xFFFF > > > def compl_one_checksum(uint16s): > > return reduce(compl_add_uint16, uint16s, 0x0000) > > > is somewhat better? > > > But is it the best way to do it with numpy? > > It's not too bad, if you only have 1D arrays to worry about (or you are only > concerned with reducing down the first axis). With a Python-implemented > function, there isn't much that will get you faster.
Yes, I only have 1D arrays in this particular problem. > > My coworker Ilan Schnell came up with a neat way to use PyPy's RPython->C > translation scheme and scipy.weave's ad-hoc extension module-building > capabilities to generate new numpy ufuncs (which have a .reduce() method) > implemented in pure RPython. > > http://conference.scipy.org/proceedings/SciPy2008/paper_16/full_text.pdf > http://svn.scipy.org/svn/scipy/branches/fast_vectorize/ > OK. Thanks. I am still a rather inexperienced SciPy and Python programmer, and I must admit that right now this seems to be in the advanced end for me. But, now that you mention weave I have given it a thought to reimplement my binary compl add function shown above using weave - if my profiler says that is where I should be spending my time optimizing. > If you have more numpy questions, please join us on the numpy mailing list. > > http://www.scipy.org/Mailing_Lists > Thank you for directing me to that numpy specific mailing list. I have been on scipy.org many times, but apparently overlooked that very prominent link to mailing lists. Slaunger > -- > Robert Kern > > "I have come to believe that the whole world is an enigma, a harmless enigma > that is made terrible by our own mad attempt to interpret it as though it > had > an underlying truth." > -- Umberto Eco- Skjul tekst i anførselstegn - > > - Vis tekst i anførselstegn - -- http://mail.python.org/mailman/listinfo/python-list
