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

[Nathaniel Smith]

On Sat, Mar 15, 2014 at 12:09 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> On Sat, 15 Mar 2014 12:55:38 +1300
> Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
>> Antoine Pitrou wrote:
>>
>> > It depends how the vectors are layed out (horizontal @ vertical or
>> > vertical @ horizontal).
>>
>> The definition of @ in the proposal is such that two
>> 1D arrays is interpreted as horizontal @ vertical.
>
> Really? That should be up to the third-party library implementing the @
> operator for its types, not to the language itself: Python _suggests_
> an use case for @, it doesn't mandate it (especially as there's no
> appropriate data type in the stdlib).

See: http://legacy.python.org/dev/peps/pep-0465/#intended-usage-details

Which begins: "This section is informative, rather than normative --
it documents the consensus of a number of libraries that provide
array- or matrix-like objects on how the @ and @@ operators will be
implemented. ..."

-- 
Nathaniel J. Smith
Postdoctoral researcher - Informatics - University of Edinburgh
http://vorpus.org