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

[jmh530]

On Wednesday, 14 March 2018 at 16:16:55 UTC, Andrei Alexandrescu 
wrote:
>
> Has row-major fallen into disuse?
> [snip]

C has always been row major and is not in disuse (the GSL library 
has gsl_matrix and that is row-major). However, Fortran and many 
linear algebra languages/frameworks have also always been column 
major. Some libraries allow both. I use Stan for Bayesian 
statistics. It has an array type and a matrix type. Arrays are 
row-major and matrices are column major. (Now that I think on it, 
an array of matrices would probably resolve most of my needs for 
an N-dimensional column major type)