On Tue, Sep 20, 2011 at 7:02 PM, Rongliang Chen <span dir="ltr"><<a href="mailto:rongliang.chan@gmail.com">rongliang.chan@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi,<br><br>I have a question about the Sparse Matrix Factorization fill. <br>Following the manual, I use the option "-info" and get the following result:<br><br>[0] MatLUFactorSymbolic_SeqAIJ(): Reallocs 0 Fill ratio:given 5 needed 5.0746e-05<br>
[0] MatLUFactorSymbolic_SeqAIJ(): Run with -pc_factor_fill 5.0746e-05 or use<br>[0] MatLUFactorSymbolic_SeqAIJ(): PCFactorSetFill(pc,5.0746e-05);<br><br>What's the numbers mean in "Reallocs 0 Fill ratio:given 5 needed 5.0746e-05"? <br>
Does the " Run with -pc_factor_fill 5.0746e-05 or use" mean that I should run my code with option " -pc_factor_fill 5.0746e-05"?<br></blockquote><div><br></div><div>"Reallocs 0": no additional malloc()s were needed</div>
<div><br></div><div>"Fill rato: give 5 needed 5.0746e-05" We guessed that the factor would need 5 times the matrix memory. It actually needed a lot less.</div><div><br></div><div>If you run -pc_factor_fill 5.0746e-05, you will get the same performance and use a lot less memory.</div>
<div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">But when I run my code with option "-snes_view", I get "factor fill ratio given 5, needed 3.28701". <br>
So what should I give to the option "-pc_factor_fill", 3.28701 or 5.0746e-05? Thanks.<br><br>Best,<br><font color="#888888">Rongliang<br>
</font></blockquote></div><br><br clear="all"><div><br></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>