[petsc-users] MatZeroRowsColumnsLocal for MatNest

[Jed Brown]

"Garth N. Wells" <gnw20 at cam.ac.uk> writes:

> As a note, with MatNest and MatZeroRowsColumns I get
>
> [0]PETSC ERROR: No support for this operation for this object type
> [0]PETSC ERROR: Mat type nest
>
> which is informative, but with MatNest and and MatZeroRowsColumnsLocal I get
>
> [0]PETSC ERROR:
> ------------------------------------------------------------------------
> [0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation,
> probably memory access out of range

Gross.  I assume Barry wrote it to call the ops->zerorowscolumns
directly to follow the same pattern as MatZeroRowsLocal (which first
checks for a special ops pointer, and then still doesn't check if
ops->zerorows is NULL).  If you need this, we'll need to add a new ops
pointer and implement it for MatNest.  If you just need a better error
message, we can just fix up the dispatch.

> Garth
>
> On 4 February 2018 at 18:43, Jed Brown <jed at jedbrown.org> wrote:
>
>> It is not implemented and it's somewhat inconsistent with the MatNest
>> philosophy of specifying everything in terms of local indices, though it
>> could be implemented.
>>
>> "Garth N. Wells" <gnw20 at cam.ac.uk> writes:
>>
>> > Should MatZeroRowsColumnsLocal work for matrices of type MATNEST?
>> >
>> > Garth
>>