Is there as "smart" built-in way to flatten a NxM matrix to a N*M vector by concatenating columns/rows, and vice versa?

For example:

Code: Select all

     3x5                         15x1
[ A D G J M ]
[ B E H K N ]  <==> [ A B C D E F G H I J K L M N O ]
[ C F I L O ]

For dense contiguous matrices, I could simply use a Map to re-interpret the underlying array, but this is very verbose. Am I missing something?

Nothing better than Map yet. To make it less verbose, you can easily write a small wrapper function for your purpose.