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

[John W. Eaton]

On  5-Dec-2007, Jason Riedy wrote:

| The current issymmetric uses the very expensive and densifying 2-norm,
| plus it checks if the matrix is Hermitian rather than symmetric.  An
| inf-norm tolerance probably is good enough.  A new routine handles
| Hermitian cases.

OK, I checked in the new function and applied the patch for
issymmetric.m.

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

?

|   Tracking down that issymmetric was running me out of memory was
|   no fun.

I don't understand the point of this comment.

|   I'd be shocked if anyone relied on the 2-norm
|   behavior, but symmetric v. Hermitian might run into problems.
| 
|   Also, Which test system is the right one?  I added routines to
|   both.  If the DejaGnu one is unused, should it be deleted?

the DejaGNU tests are obsolete, but haven't been deleted from the CVS
archive yet.

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

The tests in the test/*.m files were generated from the old DejaGNU
tests.  It would be good to migrate them to the appropriate source
files as well, but so far no one has taken on the task.  It would be
relatively easy to do, so if someone is looking for a small project...

Thanks,

jwe