[petsc-users] Is PCMG a generic PC object ?

[Jed Brown]

On Fri, Dec 3, 2010 at 20:53, Vijay S. Mahadevan <vijay.m at gmail.com> wrote:

> So this does require the fine grid matrix to be formed explicitly and
> handed over to the top level KSP solver ?
>

If you want to use Galerkin coarse operators, then you have to assemble the
fine-grid matrix.  This is an algorithmic issue, not a matter of PETSc's API
or something like that.  If you can provide matrix-free residuals/smoothers,
then you don't need to use the Galerkin procedure to build coarse operators.

Jed
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