dolfin team mailing list archive

[kent-and@xxxxxxxxx]

> On Thursday 25 September 2008, Matthew Knepley wrote:
>> This is definitely wrong. Dave and I have been doing this all week here
>> and those times are way way off.
> Sorry the time i show is the total time from the beggining of the process.
> I get the following times:
>
> ----------------------------------------------------------------------
> Solving linear system of size 566769 x 566769 (Krylov solver).
> PETSc Krylov solver (gmres, sor) converged in 35 iterations.
> Summary of timings  |  Average time  Total time  Reps
> -----------------------------------------------------
> ASSEMB_BC            |         24.42       24.42     1
> Assemble cells         |          5.33       10.66     2
> Build sparsity           |         6.305       12.61     2
> Delete sparsity         |         0.125        0.25     2
> GMRES_SOR            |         35.86       35.86     1
> Init dof map             |          0.66        2.64     4
> Init tensor                |          0.16        0.32     2
> End Process after 69.400000 seconds.
> --------------------------------------------------------------------

It seems a bit strange that only 35 iterations are required for such a
fine mesh.
Do you have a really good start vector?  Or does the initial error only
contain
high frequency errors?

Kent


>
> -----------------------------------------------------------------------
> Solving linear system of size 566769 x 566769 (Krylov solver).
> PETSc Krylov solver (gmres, ml) converged in 9 iterations.
>
> Summary of timings  |  Average time  Total time  Reps
> -----------------------------------------------------
> ASSEM_BC              |         24.38       24.38     1
> Assemble cells         |          5.33       10.66     2
> Build sparsity           |           6.3        12.6     2
> Delete sparsity         |         0.125        0.25     2
> GMRES_ML              |         79.92       79.92     1
> Init dof map            |          0.66        2.64     4
> Init tensor               |         0.165        0.33     2
> End Process after 113.450000 seconds.
>
>
>> This looks to me like ML on the entire Stokes system.
> No, i'm just testing in the the following simple system:
> ---------------------------------------------------
> Ax=b where A is given by (grad(u),grad(v))
> with u and v in VectorElement("Lagrange", "tetrahedron", 2)
> --------------------------------------------------
>
> Are this timings completly wrong?
>
>
>> > --
>> > Nuno David Lopes
>> >
>> > e-mail:ndl@xxxxxxxxxxxxxx        (FCUL/CMAF)
>> >           nlopes@xxxxxxxxxxxxxxx    (ISEL)
>> > http://ptmat.ptmat.fc.ul.pt/%7Endl/
>> >
>> > Thu Sep 25 12:30:54 WEST 2008
>> > _______________________________________________
>> > DOLFIN-dev mailing list
>> > DOLFIN-dev@xxxxxxxxxx
>> > http://www.fenics.org/mailman/listinfo/dolfin-dev
>
>
>
> --
> Nuno David Lopes
>
> e-mail:ndl@xxxxxxxxxxxxxx        (FCUL/CMAF)
>            nlopes@xxxxxxxxxxxxxxx    (ISEL)
> http://ptmat.ptmat.fc.ul.pt/%7Endl/
>
> Thu Sep 25 15:00:57 WEST 2008
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