[petsc-users] Matrix Factorization fill

Shri abhyshr at mcs.anl.gov
Tue Sep 20 22:21:53 CDT 2011


I can't reproduce this with snes/examples/tutorials/ex3.c,ex5.c, or ex19.c. Are you running a petsc example or your own application code?

Shri
----- Original Message -----
> On Sep 20, 2011, at 7:02 PM, Rongliang Chen wrote:
> 
> > Hi,
> >
> > I have a question about the Sparse Matrix Factorization fill.
> > Following the manual, I use the option "-info" and get the following
> > result:
> >
> > [0] MatLUFactorSymbolic_SeqAIJ(): Reallocs 0 Fill ratio:given 5
> > needed 5.0746e-05
> > [0] MatLUFactorSymbolic_SeqAIJ(): Run with -pc_factor_fill
> > 5.0746e-05 or use
> > [0] MatLUFactorSymbolic_SeqAIJ(): PCFactorSetFill(pc,5.0746e-05);
> >
> > What's the numbers mean in "Reallocs 0 Fill ratio:given 5 needed
> > 5.0746e-05"?
> > 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"?
> 
> This is printed incorrectly due to a change in our data structures, we
> will fix it.
> 
> >
> > But when I run my code with option "-snes_view", I get "factor fill
> > ratio given 5, needed 3.28701".
> > So what should I give to the option "-pc_factor_fill", 3.28701 or
> > 5.0746e-05? Thanks.
> 
> The 3.28701
> 
> Barrty
> 
> >
> > Best,
> > Rongliang


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