<div dir="ltr">OK, thanks.<br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Jul 15, 2014 at 2:31 PM, 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"><div class="">Brian Yang <<a href="mailto:brianyang1106@gmail.com">brianyang1106@gmail.com</a>> writes:<br>
<br>
> Thanks for the quick reply.<br>
><br>
> In the main diagonal of Matrix A, it may have some very small values, I<br>
> want to add factor to stabilize it, like:<br>
><br>
> A + alpha * I<br>
<br>
</div><a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatShift.html" target="_blank">http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatShift.html</a><br>
</blockquote></div><br><br clear="all"><br>-- <br>Brian Yang<br>U of Houston<br><br><br><br>
</div>