Darren Dale wrote: > On Tue, Sep 8, 2009 at 9:02 PM, David Cournapeau<courn...@gmail.com> wrote: >> On Wed, Sep 9, 2009 at 9:37 AM, Darren Dale<dsdal...@gmail.com> wrote: >>> Hi David, >>>> I already gave my own opinion on py3k, which can be summarized as: >>>> - it is a huge effort, and no core numpy/scipy developer has >>>> expressed the urge to transition to py3k, since py3k does not bring >>>> much for scientific computing. >>>> - very few packages with a significant portion of C have been ported >>>> to my knowledge, hence very little experience on how to do it. AFAIK, >>>> only small packages have been ported. Even big, pure python projects >>>> have not been ported. The only big C project to have been ported is >>>> python itself, and it broke compatibility and used a different source >>>> tree than python 2. >>>> - it remains to be seen whether we can do the py3k support in the >>>> same source tree as the one use for python >= 2.4. Having two source >>>> trees would make the effort even much bigger, well over the current >>>> developers capacity IMHO. >>>> >>>> The only area where I could see the PSF helping is the point 2: more >>>> documentation, more stories about 2->3 transition. >>> I'm surprised to hear you say that. I would think additional developer >>> and/or financial resources would be useful, for all of the reasons you >>> listed. >> If there was enough resources to pay someone very familiar with numpy >> codebase for a long time, then yes, it could be useful - but I assume >> that's out of the question. This would be very expensive as it would >> requires several full months IMO. >> >> The PSF could help for the point 3, by porting other projects to py3k >> and documenting it. The only example I know so far is pycog2 >> (http://mail.python.org/pipermail/python-porting/2008-December/000010.html). >> >> Paying people to do documentation about porting C code seems like a >> good way to spend money: it would be useful outside numpy community, >> and would presumably be less costly. > > Another topic concerning documentation is API compatibility. The > python devs have requested projects not use the 2-3 transition as an > excuse to change their APIs, but numpy is maybe a special case. I'm > thinking about PEP3118. Is numpy going to transition to python 3 and > then down the road transition again to the new buffer protocol? What > is the strategy here? My underinformed impression is that there isn't > one, since every time PEP3118 is considered in the context of the 2-3 > transition somebody helpfully reminds the list that we aren't supposed > to break APIs. Numpy is a critical python library, perhaps the
I'd be surprised if this is the case and if there are any issues. What Robert said applies, plus: In Python 2.6 the ndarray type would support *both* the old and the new buffer protocols, which can be usedin parallel on Python 2.6. There's no real issue on the PEP 3118 at all as I can see, it just needs to be done. I'll try hard to give this a small start (ndarray export its buffer) in November (though when the time comes I might feel that I really should be studying instead...). > transition presents an opportunity, if the community can yield a > little on numpy's C api. For example, in the long run, what would it > take to get numpy (or the core thereof) into the standard library, and > can we take steps now in that direction? Would the numpy devs be > receptive to comments from the python devs on the existing numpy > codebase? I think this one is likely a question of semantics. My feeling is that for instance the slice-returns-a-view on an array type would be hard to swallow on a standard library component? (Seeing as list returns a copy.) Python 3 kind of solved this by calling the type "memoryview", which implies that slicing returns another view. I have a feeling the the best start in this direction might be for somebody to give the memoryview type in Python 3 some love, perhaps set it up as a light-weight ndarray replacement in the standard library. (If anybody implemented fancy indexing on a memoryview I suppose it should return a new view though (through a pointer table), meaning incompatability with NumPy's fancy indexing...) > I'm willing to pitch in and work on the transition, not because I need > python-3 right now, but because the transition needs to happen and it > would benefit everyone in the long run. But I would like to know that > we are making the most of the opportunity, and have considered our > options. Well, something that may belong here: There's been some talk now and then on whether one should to port parts of the NumPy C codebase to Cython (which gives automatic Python 3 compatability, up to string/bytes issues etc.). That could probably take somewhat longer, but perhaps result in a better maintainable code base in the end which more people could work on. -- Dag Sverre _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
