On Fri, Dec 6, 2013 at 6:47 AM, Nick Coghlan <ncogh...@gmail.com> wrote:
> On 6 December 2013 11:52, Donald Stufft <don...@stufft.io> wrote: > > > > On Dec 5, 2013, at 8:48 PM, Chris Barker - NOAA Federal < > chris.bar...@noaa.gov> wrote: > > > >> What would really be best is run-time selection of the appropriate lib > >> -- it would solve this problem, and allow users to re-distribute > >> working binaries via py2exe, etc. And not require opening a security > >> hole in wheels... > >> > >> Not sure how hard that would be to do, though. > > > > Install time selectors probably isn’t a huge deal as long as there’s a > way > > to force a particular variant to install and to disable the executing > code. > > Hmm, I just had an idea for how to do the runtime selection thing. It > actually shouldn't be that hard, so long as the numpy folks are OK > with a bit of __path__ manipulation in package __init__ modules. > > Specifically, what could be done is this: > > - all of the built SSE level dependent modules would move out of their > current package directories into a suitable named subdirectory (say > "_nosse, _sse2, _sse3") > - in the __init__.py file for each affected subpackage, you would have > a snippet like: > > numpy._add_sse_subdir(__path__) > > where _add_sse_subdir would be something like: > > def _add_sse_subdir(search_path): > if len(search_path) > 1: > return # Assume the SSE dependent dir has already been added > # Could likely do this SSE availability check once at import time > if _have_sse3(): > sub_dir = "_sse3" > elif _have_sse2(): > sub_dir = "_sse2" > else: > sub_dir = "_nosse" > main_dir = search_path[0] > search_path.append(os.path.join(main_dir, sub_dir) > > With that approach, the existing wheel model would work (no need for a > variant system), and numpy installations could be freely moved between > machines (or shared via a network directory). > Hmm, taking a compile flag and encoding it in the package layout seems like a fundamentally wrong approach. And in order to not litter the source tree and all installs with lots of empty dirs, the changes to __init__.py will have to be made at build time based on whether you're building Windows binaries or something else. Path manipulation is usually fragile as well. So I suspect this is not going to fly. Ralf > To avoid having the implicit namespace packages in 3.3+ cause any > problems with this approach, the SSE subdirectories should contain > __init__.py files that explicitly raise ImportError. > > Cheers, > Nick. > > -- > Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia >
_______________________________________________ Distutils-SIG maillist - Distutils-SIG@python.org https://mail.python.org/mailman/listinfo/distutils-sig
