On Fri, Sep 18, 2009 at 7:32 AM, Niall Moran <span dir="ltr"><<a href="mailto:nmoran@thphys.nuim.ie">nmoran@thphys.nuim.ie</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Matthew Knepley wrote:<div class="im"><br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
On Thu, Sep 17, 2009 at 12:44 PM, Niall Moran <<a href="mailto:nmoran@thphys.nuim.ie" target="_blank">nmoran@thphys.nuim.ie</a> <mailto:<a href="mailto:nmoran@thphys.nuim.ie" target="_blank">nmoran@thphys.nuim.ie</a>>> wrote:<br>
<br>
Hi,<br>
<br>
I am just wondering if anything has changed on the status of this<br>
feature. Would be great to be able to perform matrix vector<br>
multiplications on complex Hermitian matrices by only providing<br>
one half of the matrix.<br>
<br>
<br>
It is not curently in the todo list since we have only had one request. It seems like it would just take being careful about the<br>
complex case for SBAIJ if you would like the try the implementation. We can answer questions.<br>
<br>
</blockquote></div>
Thanks for you rapid response. I would be interested in attempting to implement this for MPIAIJ if it would not be too involved. Would you be able to sketch a rough outline of what this would involve? Would I need to just modify the MatMult_MPIAIJ function or would I need to modify the creation of the scatterers in MatAssemblyBegin_MPIAIJ?<br>
<br>
Could anyone suggest some documentation that describes how the matrix vector multiplication works in petsc for MPIAIJ typed matrices?<br>
<br>
Does matrix vector multiplication with just the upper half work for real symmetric matrices?<br></blockquote><div><br>1) Understand the SBAIJ implementation. This is used for real symmetric matrices<br><br>2) In the places where the lower triangle is retrieved, add a complex conjugation.<br>
<br> Matt<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Regards,<br><font color="#888888">
<br>
Niall.<br>
</font></blockquote></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<br>