How about MatSetCoordindates(Mat, Vec). Then
MatNullSpaceCreateRigidBody(Mat, MatNullSpace *);
Then presumable GAMG can pass the appropriated coordinates down to the
smaller matrices it creates internally and create the rigid body null spaces it
wants as it moves to the smaller matrices?
Barry
You could have a MatGetCoordindates(Mat, Vec) and not change the calling
sequence of MatNullSpaceCreateRigidBody() but I like the first alternative I
suggested.
> On Jan 2, 2017, at 5:23 PM, Jed Brown <[email protected]> wrote:
>
> Mark Adams <[email protected]> writes:
>
>> On Mon, Jan 2, 2017 at 11:47 AM, Jed Brown <[email protected]> wrote:
>>
>>> Jeremy Theler <[email protected]> writes:
>>>
>>>> Hi all
>>>>
>>>> I want to check that the near nullspace I provide to GAMG gives "almost
>>>> null vectors" when multiplying each vector in the near nullspace against
>>>> the matrix problem.
>>>>
>>>> This way I can check that the unknown ordering I am using is consistent,
>>>> for example using by MatNullSpaceCreateRigidBody() or by computing the
>>>> nullspace by myself.
>>>
>>> Please use that and MatSetNearNullSpace(). It composes properly and you
>>> can check everything.
>>>
>>> PCSetCoordinates() happens to do double-duty for aggregation-based
>>> methods, but outside of semi-geometric methods, it is just ugly code
>>> duplication and makes assumptions that may be inappropriate (like
>>> elasticity with an interpolatory basis).
>>
>>
>> Yes, PCSetCoordinates is an old interface that is essentially deprecated.
>> Maybe we should officially deprecated this.
>
> I think we should officially deprecate it, but perhaps make something
> more general available as a Mat function (since some algorithms may use
> coordinates directly). (Needing to dig up a PC to provide problem (as
> opposed to configuration) information is bad style.)
