On Tue, Feb 8, 2022 at 2:41 PM Steven D'Aprano <st...@pearwood.info> wrote:
> On Mon, Feb 07, 2022 at 06:23:52PM +0000, Mark Dickinson wrote: > > > - Should we require IEEE 754 floating-point for > CPython-the-implementation? > > - Should we require IEEE 754 floating-point for Python-the-language? > > If the answer to those questions are Yes, that rules out using Unums, > posits, sigmoid numbers etc as the builtin float. (The terminology is a > bit vague, sorry.) Do we want that? > It does not rule anything else out should they become viable. This is just a statement that to build cpython we require ieee754 support. It does not say anything about how our Python float type is implemented internally. Should a meaningful large-os platform come along that promotes the use of a different format available from C we could make use of that and loosen the policy as needed. What updating our requirement for CPython would mean is that the likely unexercised outside our own __set_format__ using test suite "unknown_format" code in https://github.com/python/cpython/blob/main/Objects/floatobject.c could go away until such time as a platform with an actual different format springs into existence. Driveby floatobject.c code inspection: It is odd that we do ieee_be/ieee_le/unknown conditionals as a runtime check rather than configure time check as that means we compile the code for three implementations into our float implementation on all platforms despite them each using only one - I guess that was done for testing purposes presumably in the 1.x era when viable platforms were weirder as standards traction grew - today I'd call that dead code bloat. -gps > > https://ieeexplore.ieee.org/document/8080000 > > https://en.wikipedia.org/wiki/Unum_%28number_format%29 > > https://github.com/interplanetary-robot/SigmoidNumbers > > Posits are hyped as "better than IEEE-754", I have no idea if it is all > hype or if they actually are better or just different. > > > -- > Steve > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/7LUAQ32ZAHKWBJHLHUYEB7I5BZNDXGB7/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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