[petsc-users] Convergence rate for spatially varying Helmholtz system

[Matthew Knepley]

On Thu, Sep 30, 2021 at 6:58 PM Amneet Bhalla <mail2amneet at gmail.com> wrote:

>
>
>>
>>    For a diagonal system with this modest range of values Jacobi should
>> converge in a single iteration.
>>
>
> This is what I wanted to confirm (and my expectation also). There could be
> a bug in the way we are setting up the linear operators in the
> preconditioner and the matrix-free solver. We need to do some debugging.
>
> (with regard to the diagonal).
>
> We have printed the matrix and viewed it in Matlab. It is a diagonal
> matrix.
>

Can you send us the matrix? This definitely should converge in 1 iterate
now, so something I do not understand is going on.
I will take any format you've got :)

  Thanks,

     Matt

-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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