Barry Smith <[email protected]> writes: > How about MatSetCoordindates(Mat, Vec).
This would assume an interpolatory basis for which each Mat (row?)bs corresponds to one Vec bs. Should we consider mixed spaces? > Then MatNullSpaceCreateRigidBody(Mat, MatNullSpace *); Perhaps something like this as a convenience, but I think it can be useful to call the current function without first creating a Mat to attach the coordinate Vec to. > 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.)
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