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
[Numpy-discussion] numpy and cython in pure python mode
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 have not decided which way I would like better ( for "a)": 1 file might be easier to maintain, for "b)" it might be "nicer to look at" not having so many declarators "all over the place") A short example using numpy showing either way would be really nice to have ;-) One more: there is no way on reload cython-modules (yet), right ? I started looking into pyximport, but I had difficulties finding a comfortable write-test-change-test--cycle --- so far I'm using SWIG together with a makefile and recompiling and restarting the python session is similar there... Thanks, Sebastian Haase ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
