Re: deprecated functions

[Jason Riedy]

And Jaroslav Hajek writes:
>> But really I don't care about dmult.  It was a short, relatively clear
>> way to say what I meant.  Having diag * sparse be sparse is much, much
>> better.
>
> Definitely, if you ignore Matlab, it is. But it's just not that easily
> possible. I recently needed (successfully, I hope) to justify a
> compatibility breakage with much smaller impact, and it was really a
> long discussion. And it's good that it's so. I agree with John and
> David and others that Octave's compatibility with Matlab is a big plus
> for many users, including some of my colleagues.  One day, Octave may
> throw away the burden of Matlab compatibility. But I see that day
> still being far off.

My reason is that As = Dr * A * Dc should work without needing to be:
  if issparse (A),
    As = sparse (Dr) * A * sparse (Dc);
  else
    A = Dr * A * Dc;
  endif
Along with many other, similar tests that need sprinkled throughout to
make dense code work with sparse matrices.

That would be a competitive *advantage* for Octave, just like
unwind_protect is.

And for my colleagues, well, because Octave is so compatible with
Matlab(TM), they don't think it's worth changing.  And the only
place they really, really care about close compatibility is in
plotting and GUIs, and Octave ain't there.

I haven't convinced a *SINGLE* person to try Octave because it's
compatible to Matlab(TM), even with the increase in license
prices and the pain of using Matlab(TM) on a cluster.  The only
ones I have convinced have come over for *differences*, places
where Octave is superior.  The flexible native code interface is
a major one.  Amazingly, double quotes are another, as is
start-up speed (if not run over NFS).  Octaviz (VTK interface)
and MPITB (MPI interface) have helped when I fail to mention
similar Matlab(TM) packages...

Being able to express linear algebra algorithms more clearly and
concisely than in Matlab(TM) would be a useful difference.

Are there any Matlab(TM)-using textbook examples that won't work
if diagonal matrices keep sparse matrices sparse?  I really doubt
it, and that's the only place where compatibility might be worth
the stupidity.  I know compatibility brought in a short burst of
serious funding, but I don't see that happening again.

If Octave just wants to plod along after Matlab(TM), tell me, and
I'll stop working on making diagonal matrices act sensibly.

Jason