<div class="gmail_quote">On Mon, Aug 29, 2011 at 16:49, Likun Tan <span dir="ltr"><<a href="mailto:likunt@andrew.cmu.edu">likunt@andrew.cmu.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
It is 27*27 with 343 non-zeros, i use LU for all the linear equations.</blockquote></div><br><div>This is just too small and not sparse enough for sparse linear algebra to pay off. Create the same serial dense matrix redundantly on every process, factor it, put all your right hand sides for that process in a matrix B, and call MatMatSolve().</div>