<div class="gmail_quote">On Fri, Dec 3, 2010 at 20:53, Vijay S. Mahadevan <span dir="ltr"><<a href="mailto:vijay.m@gmail.com">vijay.m@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div id=":4l1">So this does require the fine grid matrix to be formed explicitly and<br>
handed over to the top level KSP solver ?</div></blockquote></div><br><div>If you want to use Galerkin coarse operators, then you have to assemble the fine-grid matrix. This is an algorithmic issue, not a matter of PETSc's API or something like that. If you can provide matrix-free residuals/smoothers, then you don't need to use the Galerkin procedure to build coarse operators.</div>
<div><br></div><div>Jed</div>