[Python-ideas] [RFC] draft PEP: Dedicated infix operators for matrix multiplication and matrix power

[Andrew Barnert]

This (or various related ideas) actually has come up somewhat regularly. I think the reason it hasn't gone anywhere is that there was never enough input from the numerical community; someone says, "I'll bet this would be useful for numerics," and someone else says "Then why haven't the numarray/numeric/numpy guys asked for it since 2000?", and nobody has an answer to that. This obviously is the answer to that.

One thing that always comes up is a suggestion for using Unicode. There are obvious downsides--the Unicode multiplication character isn't easy to type; even if Python and major code editors are fully Unicode friendly, code often has to go through channels that may not be; etc. But it's worth asking whether the numeric community has considered this and rejected it for these reasons, or for other reasons, or if they'd be happy with it but just didn't think Python was ready for it, or whatever.

Also, how do other general purpose programming languages solve this? Surely people do matrix math in Haskell and C++, at least? Do they just use separate types for matrices and arrays because they don't have to worry about duck typing (being statically-typed languages)? Do they just avoid mixing libraries together to avoid the problem? Or have people attempted to reuse % or other operators? Or (doesn't apply to C++, but does to Haskell) do they use spelled-out infix functions like `mmul` instead of trying to come up with symbolic operators? A lot of those answers wouldn't tell us anything more than "their experience isn't relevant to Python", but it would be nice to know that at least.

On Mar 13, 2014, at 19:08, Nathaniel Smith <njs at pobox.com> wrote:

> On Fri, Mar 14, 2014 at 1:59 AM, Nathaniel Smith <njs at pobox.com> wrote:
>> [...]
> 
> Hmm, not sure how that "Fwd:" snuck onto the subject line. (Or really,
> I do know, but am embarrassed to say.) Oh well, sorry, hope it isn't
> too distracting!
> 
> -n
> 
> -- 
> Nathaniel J. Smith
> Postdoctoral researcher - Informatics - University of Edinburgh
> http://vorpus.org
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