[petsc-users] Matrix-free preconditioner using shell matrix

[Jed Brown]

Praveen C <cpraveen at gmail.com> writes:

>> On 18-May-2018, at 7:46 PM, Jed Brown <jed at jedbrown.org> wrote:
>> 
>> You don't need to use a shell matrix to implement a shell
>> preconditioner.  When using a shell PC, you need to call KSPSetPC() --
>> you can unwrap that from TS -> SNES -> KSP.
>
>
> Thanks Jed.
>
> Is it the case that I cannot use a shell matrix to implement a shell preconditioner ?

They are two different concepts.  You can use either or both.