On Fri, 11 Jun 2010 00:25:17 +0200, Sturla Molden <stu...@molden.no> wrote: > Den 10.06.2010 22:07, skrev Travis Oliphant: > > > >> 2. The core should be a plain DLL, loadable with ctypes. (I know David > >> Cournapeau and Robert Kern is going to hate this.) But if Python can have > >> a custom loader for .pyd files, so can NumPy for it's core DLL. For ctypes > >> we just need to specify a fully qualified path to the DLL, which can be > >> read from a config file or whatever. > >> > > This approach does not build a new Python type in compiled code. There > > are speed disadvantages to this --- especially for the numpy scalars. > > There are at least four speed penalties in what I suggested: > > - the ctypes overhead is bigger than using Python's C API manually (or > Cython). > - there is a speed penalty for scalars and small arrays. (Previously > seen in numarray vs. numeric.) > - bytearray is a bit slower to create than to malloc a buffer. > - arrays with dtype=object > > The advantages are: > > - the code is easier to read and maintain (clean separation of Python and C) > - more portable code (no Python C API dependence) > - no obscure memory leaks to track down (bytearray instead of > malloc/free and no manual ref counting). > > > By the way: Is Cython mature enough to toss all C out the door? Since > Cython has syntax for PEP 3118 buffer objects, we should theoretically > be able to implement NumPy in Cython. Then we don't have the speed > penalty and no difficult C to maintain. But if the idea is to make a > Python independent C library from the core, it is probably a bit counter > productive...
as a long time lurker, I really like the idea of having a .so as core numpy but I'd really hate to have to go thru ctypes as a necessary (or rather, default) layer to use numpy-core from python. it of course depends on the granularity at which you wrap and use numpy-core but tight loops calling ctypes ain't gonna be pretty performance-wise. I really think using cython would be a better option. one'd get the python2 <-> python3 transition for "free". but, again, I am just a lurker here on numpy-list :) cheers, sebastien. -- ######################################### # Dr. Sebastien Binet # Laboratoire de l'Accelerateur Lineaire # Universite Paris-Sud XI # Batiment 200 # 91898 Orsay ######################################### _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
