sub_pc lu zero pivot

[Andrew T Barker]

I apparently was explicitly changing the PC in my code after PCSetFromOptions, so the options weren't getting set properly (which I found out by using -snes_view).  Sorry to bother.

Andrew

---- Original message ----
>Date: Fri, 8 Feb 2008 12:02:45 -0600
>From: "Matthew Knepley" <knepley at gmail.com>  
>Subject: Re: sub_pc lu zero pivot  
>To: petsc-users at mcs.anl.gov
>
>We would like to see:
>
>  1) The complete error message
>
>  2) The output of -snes_view so we can see exactly what solver setup you have
>
>  Thanks,
>
>     Matt
>
>On Feb 8, 2008 11:46 AM, Andrew T Barker <Andrew.Barker at colorado.edu> wrote:
>>
>> For my code on a single processor, using the options
>>
>> -ksp_type gmres -pc_type lu
>>
>> works fine, but
>>
>> -ksp_type gmres -pc_type asm -sub_pc_type lu
>>
>> produces a zero pivot.  On one processor I would expect these two to be identical, and in fact when I print out the asm submatrices (there is only one) in the second case and the original matrix in the first case, they are identical.  Even stranger is that
>>
>> -ksp_type gmres -pc_type lu -sub_pc_type lu
>>
>> also produces a zero pivot.  I would expect it to ignore the sub_pc in this case.
>>
>> Thanks for any help,
>>
>> Andrew
>>
>> ---
>> Andrew T. Barker
>> andrew.barker at colorado.edu
>> Applied Math Department
>> University of Colorado, Boulder
>> 526 UCB, Boulder, CO 80309-0526
>>
>>
>
>
>
>-- 
>What most experimenters take for granted before they begin their
>experiments is infinitely more interesting than any results to which
>their experiments lead.
>-- Norbert Wiener
>