what is default ordering method

[Barry Smith]

On Sat, 8 Apr 2006, Matthew Knepley wrote:

> On 4/8/06, buket at be.itu.edu.tr <buket at be.itu.edu.tr> wrote:
>>
>> Hi,
>>
>> I have several questions;
>>
>> Which ordering method does petsc use by default before matrix
>> factorization?
>
>

For ILU it is none (i.e. natural) for LU it is nested dissection.

For ICC and Cholesky it is natural (note the reason it is natural
for Cholesky is because of the storage of only the upper triangular
reordering is expensive.)

   Barry

> None, but external packages may use a default ordering.
>
> How can I change the restarted value of Gmres(m)?
>
>
> -ksp_gmres_restart
>
> Is there any parallel overhead when I run petsc program on single
>> processor (with mprun -np 1)?
>
>
> Not normally, since all classes are Seq by default.
>
>   Matt
>
> Thank you,
>> Best Regards,
>> Buket Benek
>>
>>
>>
>>
>>
>
>
> --
> "Failure has a thousand explanations. Success doesn't need one" -- Sir Alec
> Guiness
>