[petsc-dev] MatSetColoring

[Jed Brown]

Peter Brune <prbrune at gmail.com> writes:

> Yeah it was pretty easy to break in TS..  I thought that I might be going
> in circles here.
>
>
>>
>> It's probably worth risking the low-probability of a user depending on
>> the parameter being ignored in exchange for being able to fix this
>> inconvenience in petsc-3.4.
>>
>
> What exactly do you mean by this?  I can "fix it" for the TS case by
> replacing the error-out on the parameter with a type compare, but for a
> general user context that's not a PetscObject it's more dicey.  We could
> zero it out explicitly when setting snes_fd_coloring from options 

If at all possible, I think it _should_ be zeroed by -snes_fd_coloring.

> and expect users to do the right thing.

That was the point of my comment.  We don't think they are in the same
position as -snes_fd_coloring, but all their old code either passed NULL
or passed a valid MatFDColoring or passed NULL, and it's not very useful
to write new code that passes non-NULL.