[petsc-users] fill factor in factorization SLEPC

[jifeng zhao]

Hi Hong,

Thanks a lot. -st_redundant_pc_factor_fill does work for me. And thank you
for presenting how you found the solution. It is helpful.

Cheers,
Jifeng


On Thu, Jul 3, 2014 at 10:34 PM, Hong Zhang <hzhang at mcs.anl.gov> wrote:

> You may try -st_redundant_pc_factor_fill <fill>.
> Here is how I found the option using
> slepc-3.4.4/src/eps/examples/tutorials/ex13.c:
> 1)
> ./ex13 -info | |grep fill
> [0] MatLUFactorSymbolic_SeqAIJ(): Run with -pc_factor_fill 2.95217 or use
>
> 2)
> ./ex13 -help |grep fill
>   -st_redundant_pc_factor_fill <5>: Expected non-zeros in factored
> matrix (PCFactorSetFill)
>   -st_redundant_pc_factor_reuse_fill: <FALSE> Use fill from previous
> factorization (PCFactorSetReuseFill)
>
> i.e., the default fill=5, sufficient for this case. There is no need
> to set as 2.95217. If you want to, do
> ./ex13 -st_redundant_pc_factor_fill 2.95217 -info
> ...
> [0] MatLUFactorSymbolic_SeqAIJ(): Reallocs 0 Fill ratio:given 4 needed
> 2.95217
> [0] MatLUFactorSymbolic_SeqAIJ(): Run with -pc_factor_fill 2.95217 or use
> [0] MatLUFactorSymbolic_SeqAIJ(): PCFactorSetFill(pc,2.95217);
>
> As you see, Reallocs 0, good performance.
>
> Hong
>
> On Thu, Jul 3, 2014 at 9:45 PM, jifeng zhao
> <jifengzhao2015 at u.northwestern.edu> wrote:
> > Hi all,
> >
> > I am using SLEPC to solve an eigenvalue problem.
> >
> > I tried to add -info at run time. And I get instruction:
> >
> > MatLUFactorSymbolic_SeqAIJ(): Run with -pc_factor_fill 3.87526 or use
> > MatLUFactorSymbolic_SeqAIJ(): PCFactorSetFill(pc,3.87526);
> > MatLUFactorSymbolic_SeqAIJ(): for best performance.
> >
> > However, when I tried to add -st_pc_factor_fill 3.87526 at run time. It
> is
> > not recognized at all!
> >
> > WARNING! There are options you set that were not used!
> > WARNING! could be spelling mistake, etc!
> > Option left: name:-st_pc_factor_fill value: 3.87526
> >
> > Same things happened if I tried pc_factor_fill 3.87526
> >
> > Does anybody know how to change the fill of factorization for SLEPC?
> >
> > Thanks,
> > Jifeng Zhao
> >
> > --
> > Jifeng Zhao
> > PhD candidate at Northwestern University, US
> > Theoretical and Applied Mechanics Program
>



-- 
Jifeng Zhao
PhD candidate at Northwestern University, US
Theoretical and Applied Mechanics Program
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