Mir Slice Column or Row Major

[9il]

On Wednesday, 27 May 2020 at 16:53:37 UTC, jmh530 wrote:
> On Wednesday, 27 May 2020 at 16:07:58 UTC, welkam wrote:
>> On Wednesday, 27 May 2020 at 01:31:23 UTC, data pulverizer 
>> wrote:
>>> column major
>>
>> Cute puppies die when people access their arrays in column 
>> major.
>
> Not always true...many languages support column-major order 
> (Fortran, most obviously). The Eigen C++ library allows the 
> user to specify row major or column major. I had brought this 
> up with Ilya early on in mir and he thought it would increase 
> complexity to allow both and could also require more memory. So 
> mir is row major.

Actually it is a question of notation. For example, mir-lapack 
uses ndslice as column-major Fortran arrays. This may cause some 
headaches because the data needs to be transposed in mind. We can 
think about ndslice as about column-major nd-arrays with the 
reversed order of indexing.

The current template looks like

Slice(Iterator, size_t N = 1, SliceKind kind = 1)

If we add a special column-major notation, then it will look like

Slice(Iterator, size_t N = 1, SliceKind kind = Contiguous, 
PayloadOrder = RowMajor)

A PR that adds this feature will be accepted.