[petsc-users] GAMG issue

[Mark F. Adams]

On Mar 14, 2012, at 11:56 AM, John Mousel wrote:

> Mark,
> 
> The matrix is asymmetric. Does this require the setting of an option?

Yes:  -pc_gamg_sym_graph

Mark

> I pulled petsc-dev this morning, so I should have (at least close to) the latest code.
> 
> John
> 
> On Wed, Mar 14, 2012 at 10:54 AM, Mark F. Adams <mark.adams at columbia.edu> wrote:
> 
> On Mar 14, 2012, at 11:08 AM, John Mousel wrote:
> 
>> I'm getting the following error when using GAMG.
>> 
>> petsc-dev/src/ksp/pc/impls/gamg/agg.c:508: smoothAggs: Assertion `sgid==-1' failed.
> 
> Is it possible that your matrix is structurally asymmetric?
> 
> This code is evolving fast and so you will need to move to the dev version if you are not already using it. (I think I fixed a bug that hit this assert).
> 
>> 
>> When I try to alter the type of aggregation at the command line using -pc_gamg_type pa, I'm getting 
>> 
>> [0]PETSC ERROR: [1]PETSC ERROR: --------------------- Error Message ------------------------------------
>> [1]PETSC ERROR: Unknown type. Check for miss-spelling or missing external package needed for type:
>> see http://www.mcs.anl.gov/petsc/documentation/installation.html#external!
>> [1]PETSC ERROR: Unknown GAMG type pa given!
>> 
>> Has there been a change in the aggregation options? I just pulled petsc-dev this morning.
>> 
> 
> Yes, this option is gone now.  You can use -pc_gamg_type agg for now.
> 
> Mark
> 
>> John
> 
> 

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