[petsc-users] Laplacian at infinity

[Matthew Knepley]

On Mon, Sep 22, 2014 at 8:51 PM, John Alletto <4bikerboyjohn at gmail.com>
wrote:

>
> Are there any PML example problems using PETSc?
>

I do not believe we have any.

  Thanks,

     Matt


> John
>
>
> On Sep 22, 2014, at 7:52 AM, Matthew Knepley <knepley at gmail.com> wrote:
>
> On Mon, Sep 22, 2014 at 9:08 AM, Jed Brown <jed at jedbrown.org> wrote:
>
>> Matthew Knepley <knepley at gmail.com> writes:
>>
>> > On Mon, Sep 22, 2014 at 7:36 AM, John Alletto <4bikerboyjohn at gmail.com>
>> > wrote:
>> >
>> >> All,
>> >>
>> >> I am try to match some E&M problems with analytical solutions.
>> >> How do I deal with infinity when using a uniform grid ?
>> >>
>> >
>> > It depends on your problem. Keep making it bigger and see if you get
>> > convergence.
>>
>> This is a way to assess error caused by the finite grid, but you can
>> also use an analytic solution for that.  Using an asymptotic expansion
>> for the boundary condition can be useful (esp. when there is nonzero
>> charge in the domain, for example).  For wave propagation, look at
>> perfectly matched layers (PML).
>>
>
> PML is the best option, although many codes simply use attenuation.
>
>    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
>
>
>


-- 
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
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