[petsc-dev] DMGetMatrix --> DMGetMatrices?

[Dmitry Karpeev]

On Fri, Feb 10, 2012 at 4:02 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> On Fri, Feb 10, 2012 at 15:59, Dmitry Karpeev <karpeev at mcs.anl.gov> wrote:
>
>> As a separate matter, however, should preallocated, but not assembled
>> matrices be able to be duplicated or copied?
>>
>
> It doesn't even make semantic sense for Copy.
>
Fine.

>
> Duplicate only makes sense in that the sizes and types get set, but
> obviously the sparsity can't be set, so it doesn't have the (stated)
> semantics of Duplicate.
>
I'm not sure I follow.  If a matrix has been created, its type has been set
and it has been preallocated (e.g., MATMPIAIJ in
ksp/ksp/examples/tutorials/ex2), it is not marked as assembled until after
MatAssemblyEnd.  Does it still make sense to duplicate it?  In my opinion,
it does.

Dmitry.

>
> As currently implemented, MatDuplicate() and MatCopy() will refuse to
>> operate on a matrix that is !assembled.
>>
>
>
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