[petsc-dev] VecGetSubVector() outupt

[Barry Smith]

   So something like VecGetSubVectorDM(vec,subdm,&subvec)? I hate having so many functions but don't see how to avoid it. Or

VecGetSubVectorDM(vec,PetscInt numfields,PetscInt *fields,&subvec)?   The problem with this one is each new call has to create a new subdm unless we stash it in the DM.




> On Nov 7, 2016, at 6:17 AM, Matthew Knepley <knepley at gmail.com> wrote:
> 
> The way we have chosen to manage Vec output is to override the VecView function with DM-specific output functions. This strategy is currently broken for VecGetSubVector().
> 
> Really what we want is for the Vec to have the correct subdm if indeed it is a subfield. However, its possible that the IS is some random thing, like points intersecting some surface, so we don't want it to blindly copy over the function pointers.
> 
> How about we supplement DMCreateSubDM() with VecGetSubvectorDM(), which calls it underneath and sets up the vector correctly?
> 
>    Matt
> 
> -- 
> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
> -- Norbert Wiener