On Sat, Feb 18, 2012 at 1:40 PM, Charles R Harris <charlesr.har...@gmail.com> wrote: > > > On Sat, Feb 18, 2012 at 2:17 PM, David Cournapeau <courn...@gmail.com> > wrote: >> >> On Sat, Feb 18, 2012 at 8:45 PM, Charles R Harris >> <charlesr.har...@gmail.com> wrote: >> > >> > >> > On Sat, Feb 18, 2012 at 1:39 PM, Matthew Brett <matthew.br...@gmail.com> >> > wrote: >> >> >> >> Hi, >> >> >> >> On Sat, Feb 18, 2012 at 12:35 PM, Charles R Harris >> >> <charlesr.har...@gmail.com> wrote: >> >> > >> >> > >> >> > On Sat, Feb 18, 2012 at 12:21 PM, Matthew Brett >> >> > <matthew.br...@gmail.com> >> >> > wrote: >> >> >> >> >> >> Hi. >> >> >> >> >> >> On Sat, Feb 18, 2012 at 12:18 AM, Christopher Jordan-Squire >> >> >> <cjord...@uw.edu> wrote: >> >> >> > On Fri, Feb 17, 2012 at 11:31 PM, Matthew Brett >> >> >> > <matthew.br...@gmail.com> wrote: >> >> >> >> Hi, >> >> >> >> >> >> >> >> On Fri, Feb 17, 2012 at 10:18 PM, Christopher Jordan-Squire >> >> >> >> <cjord...@uw.edu> wrote: >> >> >> >>> On Fri, Feb 17, 2012 at 8:30 PM, Sturla Molden >> >> >> >>> <stu...@molden.no> >> >> >> >>> wrote: >> >> >> >>>> >> >> >> >>>> >> >> >> >>>> Den 18. feb. 2012 kl. 05:01 skrev Jason Grout >> >> >> >>>> <jason-s...@creativetrax.com>: >> >> >> >>>> >> >> >> >>>>> On 2/17/12 9:54 PM, Sturla Molden wrote: >> >> >> >>>>>> We would have to write a C++ programming tutorial that is >> >> >> >>>>>> based >> >> >> >>>>>> on >> >> >> >>>>>> Pyton knowledge instead of C knowledge. >> >> >> >>>>> >> >> >> >>>>> I personally would love such a thing. It's been a while since >> >> >> >>>>> I >> >> >> >>>>> did >> >> >> >>>>> anything nontrivial on my own in C++. >> >> >> >>>>> >> >> >> >>>> >> >> >> >>>> One example: How do we code multiple return values? >> >> >> >>>> >> >> >> >>>> In Python: >> >> >> >>>> - Return a tuple. >> >> >> >>>> >> >> >> >>>> In C: >> >> >> >>>> - Use pointers (evilness) >> >> >> >>>> >> >> >> >>>> In C++: >> >> >> >>>> - Return a std::tuple, as you would in Python. >> >> >> >>>> - Use references, as you would in Fortran or Pascal. >> >> >> >>>> - Use pointers, as you would in C. >> >> >> >>>> >> >> >> >>>> C++ textbooks always pick the last... >> >> >> >>>> >> >> >> >>>> I would show the first and the second method, and perhaps >> >> >> >>>> intentionally forget the last. >> >> >> >>>> >> >> >> >>>> Sturla >> >> >> >>>> >> >> >> >> >> >> >> >>> On the flip side, cython looked pretty...but I didn't get the >> >> >> >>> performance gains I wanted, and had to spend a lot of time >> >> >> >>> figuring >> >> >> >>> out if it was cython, needing to add types, buggy support for >> >> >> >>> numpy, >> >> >> >>> or actually the algorithm. >> >> >> >> >> >> >> >> At the time, was the numpy support buggy? I personally haven't >> >> >> >> had >> >> >> >> many problems with Cython and numpy. >> >> >> >> >> >> >> > >> >> >> > It's not that the support WAS buggy, it's that it wasn't clear to >> >> >> > me >> >> >> > what was going on and where my performance bottleneck was. Even >> >> >> > after >> >> >> > microbenchmarking with ipython, using timeit and prun, and using >> >> >> > the >> >> >> > cython code visualization tool. Ultimately I don't think it was >> >> >> > cython, so perhaps my comment was a bit unfair. But it was >> >> >> > unfortunately difficult to verify that. Of course, as you say, >> >> >> > diagnosing and solving such issues would become easier to resolve >> >> >> > with >> >> >> > more cython experience. >> >> >> > >> >> >> >>> The C files generated by cython were >> >> >> >>> enormous and difficult to read. They really weren't meant for >> >> >> >>> human >> >> >> >>> consumption. >> >> >> >> >> >> >> >> Yes, it takes some practice to get used to what Cython will do, >> >> >> >> and >> >> >> >> how to optimize the output. >> >> >> >> >> >> >> >>> As Sturla has said, regardless of the quality of the >> >> >> >>> current product, it isn't stable. >> >> >> >> >> >> >> >> I've personally found it more or less rock solid. Could you say >> >> >> >> what >> >> >> >> you mean by "it isn't stable"? >> >> >> >> >> >> >> > >> >> >> > I just meant what Sturla said, nothing more: >> >> >> > >> >> >> > "Cython is still 0.16, it is still unfinished. We cannot base >> >> >> > NumPy >> >> >> > on >> >> >> > an unfinished compiler." >> >> >> >> >> >> Y'all mean, it has a zero at the beginning of the version number and >> >> >> it is still adding new features? Yes, that is correct, but it seems >> >> >> more reasonable to me to phrase that as 'active development' rather >> >> >> than 'unstable', because they take considerable care to be backwards >> >> >> compatible, have a large automated Cython test suite, and a major >> >> >> stress-tester in the Sage test suite. >> >> >> >> >> > >> >> > Matthew, >> >> > >> >> > No one in their right mind would build a large performance library >> >> > using >> >> > Cython, it just isn't the right tool. For what it was designed for - >> >> > wrapping existing c code or writing small and simple things close to >> >> > Python >> >> > - it does very well, but it was never designed for making core C/C++ >> >> > libraries and in that role it just gets in the way. >> >> >> >> I believe the proposal is to refactor the lowest levels in pure C and >> >> move the some or most of the library superstructure to Cython. >> > >> > >> > Go for it. >> >> The proposal of moving to a core C + cython has been discussed by >> multiple contributors. It is certainly a valid proposal. *I* have >> worked on this (npymath, separate compilation), although certainly not >> as much as I would have wanted to. I think much can be done in that >> vein. Using the "shut up if you don't do it" is a straw man (and >> uncalled for). > > > OK, I was annoyed.
By what? Best, Matthew _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
