[petsc-users] elimination of trivial entries in a matrix

[Barry Smith]

  -pc_type redistribute -ksp_type preonly -redistribute_ksp_type gmres -redistribute_ksp_monitor -redistribute_pc_type mycoolpreconditioner

   Barry

On Oct 11, 2011, at 9:43 AM, Dominik Szczerba wrote:

> That sounds really great, but I do not seem to find any examples how
> to use it. I would be grateful for a few more pointers.
> 
> Regards,
> Dominik
> 
> On Tue, Oct 11, 2011 at 4:31 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>> 
>>  Dominik,
>> 
>>      This is handled by PCREDISTRIBUTE
>> 
>>   Barry
>> 
>> On Oct 11, 2011, at 9:06 AM, Dominik Szczerba wrote:
>> 
>>> My matrix has many trivial entries (A_{ii}=1, A_{i!=j}=0, b_i = b0)
>>> that I want to eliminate to reduce the solving time, re-inserting them
>>> at the end into the solution vector.
>>> Of course I can do it all by creating a second matrix and doing
>>> related book-keeping on my own, but was wondering if there is some
>>> functionality in Petsc to facilitate it.
>>> If so, I would be grateful for just a list of relevant functions to look at.
>>> 
>>> Many thanks
>>> Dominik
>> 
>>