<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div><br></div><div><font size="4">Are there any PML example problems using PETSc?</font></div><div><br></div><div>John</div><div><br></div><br><div><div>On Sep 22, 2014, at 7:52 AM, Matthew Knepley <<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Sep 22, 2014 at 9:08 AM, Jed Brown <span dir="ltr"><<a href="mailto:jed@jedbrown.org" target="_blank">jed@jedbrown.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Matthew Knepley <<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>> writes:<br>
<br>
> On Mon, Sep 22, 2014 at 7:36 AM, John Alletto <<a href="mailto:4bikerboyjohn@gmail.com">4bikerboyjohn@gmail.com</a>><br>
> wrote:<br>
><br>
>> All,<br>
>><br>
>> I am try to match some E&M problems with analytical solutions.<br>
>> How do I deal with infinity when using a uniform grid ?<br>
>><br>
><br>
> It depends on your problem. Keep making it bigger and see if you get<br>
> convergence.<br>
<br>
This is a way to assess error caused by the finite grid, but you can<br>
also use an analytic solution for that. Using an asymptotic expansion<br>
for the boundary condition can be useful (esp. when there is nonzero<br>
charge in the domain, for example). For wave propagation, look at<br>
perfectly matched layers (PML).<br>
</blockquote></div><br>PML is the best option, although many codes simply use attenuation.</div><div class="gmail_extra"><br></div><div class="gmail_extra"> Matt<br clear="all"><div><br></div>-- <br>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener
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