diagonal matrices specializations

[Bill Denney]

Jaroslav Hajek wrote:
> Yes, that is of course possible, just I wasn't sure whether it's the
> right thing. If the
> Octave's hdf5 format is only supposed to be read by Octave, then that's OK.

So, I've not followed all of this in detail, but it seems to me that
loading a variable from disk would take significantly longer than the
determination if it is a diagonal matrix.  How difficult would it be to
save files using the full format (or as a sparse matrix which probably
makes more sense) and upon loading determine if it is diagonal and make
it have the right class then.  That should work for all external formats

I may be way off, but that seems like the best way to deal with diagonal
matrices when loading and with external formats.

Have a good day,

Bill