[petsc-users] PaStix is slower in pestc-dev

[Xiangdong Liang]

On Sun, Dec 11, 2011 at 9:04 AM, Matthew Knepley <knepley at gmail.com> wrote:
> On Sun, Dec 11, 2011 at 12:05 AM, Xiangdong Liang <xdliang at gmail.com> wrote:
>>
>> Hello PETSc team,
>>
>> I was using PaStiX within petsc 3.1-p8. Today, I am trying PaStiX
>> within petsc-dev. However, For the same code, solving the same linear
>> system takes longer time (120s vs 90s) in petsc-dev. Both are compiled
>> with debugging mode off. Is it possible that the newer PaStiX is
>> slower than old version? or due to some options in compiling?
>
>
> It is likely the options are not exactly the same, meaning the ordering is
> different,
> etc. Did you check everything wiht -ksp_view and -ksp_monitor?

I  use ksp_view, ksp_monitor options and same -pc_factor_zeropivot
1e-12, the dev version is still slower. One difference I see from
pastix_verbose is the option of Pastix:

In pets-3.1: I have

      DISTRIBUTED         :                  Not defined
       FLUIDBOX            :                  Not defined
       METIS               :                  Not defined


While in petsc-dev, I have

      DISTRIBUTED         :                   Defined
        METIS               :                   Not defined
        WITH_SCOTCH         :                   Defined


However, I do not understand these options. Could that be the reason?

Xiangdong

>
>    Matt
>
>>
>> Best,
>> Xiangdong
>>
>> PS. I cannot use PaStiX in 3.2 because in the runtime, PaStiX crashed
>> due to missing of the option -DWITHSCOTCH during compiling. It was
>> reported before by one user and fixed in petsc-dev, but not in
>> petsc-3.2-p5.
>>
>> http://lists.mcs.anl.gov/pipermail/petsc-users/2011-March/008356.html
>
>
>
>
> --
> What most experimenters take for granted before they begin their experiments
> is infinitely more interesting than any results to which their experiments
> lead.
> -- Norbert Wiener