Got it, Thank you.<div><br></div><div>Robb<br><br><div class="gmail_quote">On Sun, Sep 18, 2011 at 5:50 PM, Barry Smith <span dir="ltr"><<a href="mailto:bsmith@mcs.anl.gov">bsmith@mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div><div></div><div class="h5"><br>
On Sep 18, 2011, at 11:51 AM, Panruo Wu wrote:<br>
<br>
> Dear list,<br>
><br>
> I read in the MatSetValues documentation and found that<br>
><br>
> Negative indices may be passed in idxm and idxn, these rows and columns are simply ignored<br>
><br>
> I wonder if it's still the case when passing row or column indices larger than matrix dimensions.<br>
> If it's true it's very handy to assemble matrix of homogeneous dirichlet boundary condition.<br>
<br>
</div></div> No, you need to label those nodes with negative indices to get them ignored; larger than N will generate an error.<br>
<br>
Note if you provide your own local to global mapping to the matrix you can map the "extra" large values to negative values and thus have them ignored. But I recommend since labeling all nodes you want ignored with negative indices.<br>
<br>
Barry<br>
<br>
><br>
> Thanks,<br>
> Robb<br>
<br>
</blockquote></div><br></div>