On Thu, Mar 31, 2011 at 11:45 AM, Ralf Gommers <ralf.gomm...@googlemail.com>wrote:
> On Thu, Mar 31, 2011 at 8:37 PM, Eli Stevens (Gmail) > <wickedg...@gmail.com> wrote: > > On Thu, Mar 31, 2011 at 10:40 AM, Ralf Gommers > > <ralf.gomm...@googlemail.com> wrote: > >> It would definitely need to get into beta 2, and even then I'm a > >> little hesitant to push in such a change at the last moment. > > > > If I miss the 1.6.0b2 cutoff, would a change like this be appropriate > > for 1.6.1, or will it need to wait until 1.7.0? I wish I'd known that > > half floats were going to be in 1.6.0 (the bug tracker says 2.0); I'd > > have started working on this a few weeks earlier. :) > > There likely will not be a 1.7.0, if things with 2.0 go according to > plan. It probably wouldn't be a very appropriate change for 1.6.1. > > > > >> It would > >> need some testing with other libraries that use the numpy buffer > >> protocol. > > > > I am currently working on a patch for cython to accept half-floats. > > ATM, it is able to accept the data from numpy (though it does not yet > > handle the bit-fiddling to expand the values into a float32 on read, > > nor collapse it from a float32 back into a float16 on write). The > > code change to numpy was literally a one-line change to add NPY_HALF > > to a switch statement (though I haven't tried to import half floats > > yet). Is one other library enough, or will I need to find another > > library to patch as well? I think that OpenCL would probably be my > > next choice, since I think that we'll eventually want float16 support > > there too. > > If it works with Cython I think that's enough. With other libraries I > did not mean that you should write patches for those, just some > testing to make sure the change is 100% backwards compatible. > > >> Also, reading back the thread, Pauli seemed to disagree with > >> this. > > > > On Fri, Mar 25, 2011 at 10:21 AM, Pauli Virtanen <p...@iki.fi> wrote: > >> The buffer interface cannot be used to export the half-float types, > since > >> the type is not specified in PEP 3118. Numpy cannot unilaterally add > >> nonstandard format codes to the spec. > > > > I'm currently in the process of submitting a patch to CPython to > > update the struct module to handle half-floats. So far, the response > > on python-ideas has been generally positive (a couple +1s from people > > with commit bits, GVR has chimed in on the thread with an aside (but > > not an objection), etc.). Unless I'm misunderstanding the objection, > > making half-floats an official part of the spec (the discussion on > > python-ideas explicitly notes that numpy driving force behind the > > change) would satisfy Pauli's concern. > > > > Next up for me is to get a patch onto the CPython issue tracker, but > > as soon as I have that done, I'll start working on adding unit tests > > to my numpy fork. I anticipate being able to get that done today. > > Sounds good. > > I've committed the patch adding 'e' to the buffer protocol and back-ported it to the 1.6.x branch. This leaves the testing with Cython and getting consensus from CPython about the letter to use in the struct module/buffer interface. -Mark
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