[PATCH] Use the inf-norm rather than 2-norm in issymmetric; add ishermitian.

[Jason Riedy]

And John W. Eaton writes:
> OK, I checked in the new function and applied the patch for
> issymmetric.m.

Thanks!

>> Signed-off-by: Jason Riedy <ejr at cs.berkeley.edu>
> ?

Sorry, my habit of adding -s to git-format-patch.  (No, I'm
not advocating a switch.  I just track your CVS repo with git.)

>> Tracking down that issymmetric was running me out of memory was
>> no fun.
>
> I don't understand the point of this comment.

I was pretty surprised.  How difficult would it be to warn on
sparse->dense conversions?  It seems suddenly to be a popular
problem; the sum() one likely is biting me, too.  The warning
could be off by default.  Think I'll try it and see how noisy it
gets.

Would ov-*-sparse.cc's *_array_value() and *_matrix_value()
be good points for that warning?  I'm not sure what the
"dense but sparse" to dense conversion uses, or where the
code is to check.

> New tests should be added to the source files themselves, so I added
> your tests to ishermitian.m and issymmetric.m.

Thank you!

> It would be relatively easy to do, so if someone is looking for a
> small project...

Unfortunately, I have a mountain of large projects that come
first...

Jason