Re: [Numpy-discussion] numpy and cython in pure python mode
Thanks for all the replies ! On Wed, Sep 23, 2009 at 4:55 AM, Dag Sverre Seljebotn wrote: > Robert Kern wrote: >> On Tue, Sep 22, 2009 at 01:33, Sebastian Haase wrote: >> >>> Hi, >>> I'm not subscribed to the cython list - hoping enough people would >>> care to justify my post here: >>> > The post might be justified, but it is a question of available knowledge > as well. I nearly missed this post here. The Cython user list is on: > > http://groups.google.com/group/cython-users > >>> I know that cython's numpy is still getting better and better over >>> time, but is it already today possible to have numpy support when >>> using Cython in "pure python" mode? >>> I like the idea of being able to develop and debug code "the python >>> way" -- and then just switching on the cython-overdrive mode. >>> (Otherwise I have very good experience using C/C++ with appropriate >>> typemaps, and I don't mind the C syntax) >>> >>> I only recently learned about the "pure python" mode on the sympy list >>> (and at the EuroScipy2009 workshop). >>> My understanding is that Cython's pure Python mode could be "played" >>> in two ways: >>> a) either not having a .pyx-file at all and putting everything into a >>> py-file (using the "import cython" stuff) >>> or b) putting only cython specific declaration in to a pyx file having >>> the same basename as the py-file next to it. >>> > That should be a pxd file with the same basename. And I think that mode > should work. b), that is. That is really good news ! A short example would be very helpful, since the "pure python mode" documentation is very sparse. I found that one wiki page to be very good - but obviously it's not a complete reference. > > Sturla's note on the memory view syntax doesn't apply as that's not in a > released version of Cython yet, and won't be until 0.12.1 or 0.13. But > that could be made to support Python mode a). > Using an svn version would be fine with me, however the mentioned syntax (thanks Sturla) looks quite awkward/unnatural. > Finally there's been some recent discussion on cython-dev about a tool > which can take a pyx file as input and output pure Python. This would probably only be a second-to-best solution because it would effectively double the source code. (However, eventually such a tool could run behind the scene and import the pyx-converted py file on the fly -- in which case it would be transparent ...) >> >>> One more: there is no way on reload cython-modules (yet), right ? >>> >> >> Correct. There is no way to reload any extension module. >> > This can be worked around (in most situations that arise in practice) by > compiling the module with a new name each time and importing things from > it though. Sage already kind of support it (for the %attach feature > only), and there are patches around for pyximport in Cython that's just > lacking testing and review. Since pyximport lacks a test suite > altogether, nobody seems to ever get around to that. > I read something like this in the archives, thanks for the update. Will those patches be applied to svn - even if untested so far... ? > Dag Sverre Thanks Dag. -- Sebastian Haase ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] numpy and cython in pure python mode
Robert Kern wrote: > On Tue, Sep 22, 2009 at 01:33, Sebastian Haase wrote: > >> Hi, >> I'm not subscribed to the cython list - hoping enough people would >> care to justify my post here: >> The post might be justified, but it is a question of available knowledge as well. I nearly missed this post here. The Cython user list is on: http://groups.google.com/group/cython-users >> I know that cython's numpy is still getting better and better over >> time, but is it already today possible to have numpy support when >> using Cython in "pure python" mode? >> I like the idea of being able to develop and debug code "the python >> way" -- and then just switching on the cython-overdrive mode. >> (Otherwise I have very good experience using C/C++ with appropriate >> typemaps, and I don't mind the C syntax) >> >> I only recently learned about the "pure python" mode on the sympy list >> (and at the EuroScipy2009 workshop). >> My understanding is that Cython's pure Python mode could be "played" >> in two ways: >> a) either not having a .pyx-file at all and putting everything into a >> py-file (using the "import cython" stuff) >> or b) putting only cython specific declaration in to a pyx file having >> the same basename as the py-file next to it. >> That should be a pxd file with the same basename. And I think that mode should work. b), that is. Sturla's note on the memory view syntax doesn't apply as that's not in a released version of Cython yet, and won't be until 0.12.1 or 0.13. But that could be made to support Python mode a). Finally there's been some recent discussion on cython-dev about a tool which can take a pyx file as input and output pure Python. > >> One more: there is no way on reload cython-modules (yet), right ? >> > > Correct. There is no way to reload any extension module. > This can be worked around (in most situations that arise in practice) by compiling the module with a new name each time and importing things from it though. Sage already kind of support it (for the %attach feature only), and there are patches around for pyximport in Cython that's just lacking testing and review. Since pyximport lacks a test suite altogether, nobody seems to ever get around to that. Dag Sverre ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] numpy and cython in pure python mode
On Tue, Sep 22, 2009 at 01:33, Sebastian Haase wrote: > Hi, > I'm not subscribed to the cython list - hoping enough people would > care to justify my post here: > > I know that cython's numpy is still getting better and better over > time, but is it already today possible to have numpy support when > using Cython in "pure python" mode? > I like the idea of being able to develop and debug code "the python > way" -- and then just switching on the cython-overdrive mode. > (Otherwise I have very good experience using C/C++ with appropriate > typemaps, and I don't mind the C syntax) > > I only recently learned about the "pure python" mode on the sympy list > (and at the EuroScipy2009 workshop). > My understanding is that Cython's pure Python mode could be "played" > in two ways: > a) either not having a .pyx-file at all and putting everything into a > py-file (using the "import cython" stuff) > or b) putting only cython specific declaration in to a pyx file having > the same basename as the py-file next to it. I'm pretty sure that you need Cython syntax that is not supported by the pure-Python mode in order to use numpy arrays effectively. > One more: there is no way on reload cython-modules (yet), right ? Correct. There is no way to reload any extension module. -- 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 ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] numpy and cython in pure python mode
Sebastian Haase skrev: > I know that cython's numpy is still getting better and better over > time, but is it already today possible to have numpy support when > using Cython in "pure python" mode? > I'm not sure. There is this odd memoryview syntax: import cython view = cython.int[:,:](my2darray) print view[3,4] # fast when compiled, according to Sverre S.M. ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
