Weird (?) results obtained from experiments with the SNESMF module

Lisandro Dalcin dalcinl at
Fri Dec 19 13:15:02 CST 2008

Hi, Rafael.

Did you make sure to pass '-pc_type none' for both JFNK and NK?? If
you do not explicitely pass it to NK, you will end-up by default using
a preconditioner: ILU(0) in uniprocessors runs and Block-Jacobi with
ILU(0) on each local block with two or more processors.... In short,
pass always pass '-pc_type none' when comparing matrix-free and and
non-matrix-free iterations .... If not, the comparison will not be
fair ...

On Fri, Dec 19, 2008 at 4:33 PM, Rafael Santos Coelho
<rafaelsantoscoelho at> wrote:
> Oh, and one more thing: lambda = 4.0 was the Bratu parameter chosen for all
> tests.

Lisandro Dalcín
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
PTLC - Güemes 3450, (3000) Santa Fe, Argentina
Tel/Fax: +54-(0)342-451.1594

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