[petsc-users] PCMGSetGalerkin() new inputs

[Jed Brown]

This wasn't explained well in the commit message.  The old code used the
Galerkin procedure on the "Pmat" (preconditioning matrix; which may or
may not be the same as the Amat) and set the result as both Amat and
Pmat of the coarse grid.  The new code allows you to specify.  If your
Amat and Pmat are the same on the finest level, then BOTH will offer the
same behavior as before.

Myriam Peyrounette via petsc-users <petsc-users at mcs.anl.gov> writes:

> Hi,
>
> I am currently comparing two codes based on PETSc. The first one uses
> PETSC 3.6.4 and the other one PETSc 3.10.2.
>
> I am having a look at the use of the function PCMGSetGalerkin(). With
> PETSc 3.6, the input is a boolean, while it is either
> PC_MG_GALERKIN_MAT, PC_MG_GALERKIN_PMAT or PC_MG_GALERKIN_BOTH with PETSc 3.10.
>
> Which one of these new inputs should I use to have the same
> configuration as with PETSc 3.6?
>
> Thanks in advance,
>
> -- 
> Myriam Peyrounette
> CNRS/IDRIS - HLST
> --