> On May 6, 2015, at 5:24 PM, Gideon Simpson <[email protected]> wrote:
>
> What are the relative merits of DMGetGlobalVector and DMCreateGlobalVector,
> and the analogous question for the Local Vectors? Are there scenarios where
> one should be used over the other?
Get are intended for obtaining work vectors that one intends to restore
soon, likely in the same function that did the get. Create is for long living
vectors that you are likely passing around to solvers, subroutines etc.
Explanation: sometimes a subroutine needs some work vectors. For example
often a PETSc SNESFormFunction will do a DMGlobalToLocalBegin/End() at the
beginning to allow access of ghost values. That local vector is only needed in
that subroutine so one should use the get.
>
> -gideon
>
