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. Best, Matthew _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion