[petsc-dev] [petsc-users] MATNEST with shell matrices

[Boyce Griffith]

On 2/21/13 8:57 PM, Jed Brown wrote:
>
> On Thu, Feb 21, 2013 at 7:53 PM, Boyce Griffith <griffith at cims.nyu.edu
> <mailto:griffith at cims.nyu.edu>> wrote:
>
>
>     These applications are mainly transient solvers in which regridding
>     happens "between" time steps.
>
>
>
> Okay, what if YourSolver(X) takes time steps? The old Vec remembers what
> space it used to be part of?

Sorry for the delay.  The thing that "owns" the data that the Vec 
represents also manages regridding and interpolation between grids.  So 
if you had something that did time stepping, the old Vec would get the 
rug pulled out from under it if YourSolver(X) regridded things.  (It 
doesn't have to be this way --- you could have different AMR grids 
floating around --- but this is how all of the transient solvers 
currently work in the code.)

-- Boyce