Do we need Mat, Vec, TMmat, Diag, Sym and other matrix types?

[Andrei Alexandrescu]

On 03/14/2018 01:01 AM, 9il wrote:
> On Tuesday, 13 March 2018 at 17:10:03 UTC, jmh530 wrote:
>> "Note that using row-major ordering may require more memory and time 
>> than column-major ordering, because the routine must transpose the 
>> row-major order to the column-major order required by the underlying 
>> LAPACK routine."
> 
> Maybe we should use only column major order. --Ilya

Has row-major fallen into disuse?

Generally: it would be great to have a standard collection of the 
typical data formats used in linear algebra and scientific coding. This 
would allow interoperation without having each library define its own 
types with identical layout but different names. I'm thinking of:

* multidimensional hyperrectangular
* multidimensional jagged
* multidimensional hypertriangular if some libraries use it
* sparse vector (whatever formats are most common, I assume array of 
pairs integral/floating point number, with the integral either before or 
after the floating point number)

No need for a heavy interface on top of these. These structures would be 
low-maintenance and facilitate a common data language for libraries.


Andrei