Using parMetis in petsc for ordering

[Dimitri Lecas]

Barry Smith a écrit :
>   
>
> On Thu, 11 Jan 2007, Dimitri Lecas wrote:
>
>   
>> Barry Smith a �crit :
>>     
>>>   Dimitri,
>>>
>>>    No, I think this is not the correct way to look at things. Load
>>> balancing the original matrix is not neccessarily a good thing for
>>> doing an LU factorization (in fact it is likely just to make the LU
>>> factorization have much more fill and require much more floating
>>> operations). 
>>>   Packages like SuperLU_dist and Mumps have their own internal ordering
>>> routines that are specifically for getting a good ordering for doing
>>> the parallel LU factorization, you should just have these solvers
>>> use them (which they do automatically).
>>>
>>>    Barry
>>>
>>>
>>> On Thu, 11 Jan 2007, Dimitri Lecas wrote:
>>>
>>>   
>>>       
>> I'am no longer talking about doing LU factorization. But use iterative method
>> for solving a linear system, like bicg. Like in the ex10. In this example i
>> don't understand why using MatPartitioning.
>>     
>
>   Please rephrase the question. Are you asking why one should do the partition 
> or why one should not? Are you asking in the case where the matrix is read from
> disk or generated in a parallel program?
>
>   
I try to understand the interest to call MatPartitioning before solving 
the linear system with the same matrix. (Like 
ksp/examples/tutorials/ex10.c).

-- 
Dimitri Lecas