changes for next PETSc release

[Lisandro Dalcin]

On 3/16/08, Barry Smith <bsmith at mcs.anl.gov> wrote:
>      There are two significant  changes I'd like to see before the
>  next PETSc release:
>
>  1) remove the overly complicated (from a user perspective) matrix
>  subclassing for the various external
>       matrix solver packages and replace with MatSolverSetType() -
>  mat_solver_type <type> that simply
>       flips the various factorization/solver functions with those
>  requested and

I'm definitely +1 on this. Switching to different LU solvers is a
mayor pain, at least compared to KSP's or PC's.

>  2) properly name-space PETSc by putting a Petsc in front of all PETSc
>  objects, function names etc
>       (this will require changing a few names also to keep them below
>  the 32 character limit).

Do you mean all the IS,Vec,Mat,KSP,PC,SNES,TS interfaces? Such a
change would affect almost everything.

> This will
>       be very painful change for some users who are not comfortable
>  ever changing code, hence I hesitate
>       to do it, but it is the right thing to do and should have been
>  done originally.

Yes, end users will definitely cry. However, you can still do that
with some backward compatibility mechanism. Basically, PETSc could
provide some compatibility headers plenty of typedef's and #defines's
providing access to the old naming convention. We can even maintain
that compatibility headers for a few releases. How many releases?
Perhaps forever. I'm afraid that this approach would just delay the
conversion process of all code out there. If at some time we stop
maintaining the compatibily macros, then the real problem (users not
updating code) will definitely appear, but now in the future.

In short, I'm +1 in properly name-space all stuff. But such a change
should be paired to a backward compatibility mechanism.





>  .
>
>      Maybe we can do a release in around a couple of months, it would
>  be 2.4
>
>
>     Barry
>
>
>


-- 
Lisandro Dalcín
---------------
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