I performed some tests with the tutorial 55. I noted that the some issue
shows up here, too.
Especially it occurs when I try solving the 3D problem after 5 refinement
cycles.
Changing the following part of code :
BlockDynamicSparsityPattern dsp(dofs_per_block, dofs_per_block);
DoFTools::make_sparsity_pattern(dof_handler, coupling, dsp,
constraints, false);
SparsityTools::distribute_sparsity_pattern(
dsp,
dof_handler.compute_locally_owned_dofs_per_processor(),
mpi_communicator,
locally_relevant_dofs);
system_matrix.reinit(owned_partitioning, dsp, mpi_communicator);
with this one:
TrilinosWrappers::BlockSparsityPattern
sp(owned_partitioning,MPI_COMM_WORLD);
DoFTools::make_sparsity_pattern(dof_handler,
coupling,
sp,
constraints,
false,
Utilities::MPI::this_mpi_process(mpi_communicator));
sp.compress();
system_matrix.reinit(sp);
everything works fine.
Obviously I changed the same part for making the preconditioner sparsity
pattern.
I think that this test case can help you to figure out what is going on.
Thanks,
Matteo
Il giorno gio 10 ott 2019 alle ore 22:41 Wolfgang Bangerth <
[email protected]> ha scritto:
> On 10/9/19 10:26 AM, Matteo Frigo wrote:
> >
> > I'm saying that making a DynamicSparsityPattern by using the procedure
> > described above is more expensive (from the memory point of view)
> respect
> > using TrilinosWrappers::BlockSparsityPattern.
> > I noted this trouble trying to run some test cases with a large number
> of
> > unknowns (100 millions of dofs).
> > In such cases, I get an out of memory error if I use
> DynamicSparsityPattern,
> > whereas it works fine using TrilinosWrappers::BlockSparsityPattern.
> > Investigating on smaller cases, I noted that a peak of memory usage
> occurs
> > during the call of the function:
> > DoFTools::make_sparsity_pattern(dof_handler, scratch_coupling, dsp,
> > constraints, false, this_mpi_process);
> > It means that the problem remains, even if the program runs until the
> end.
> > As far as the analysis of memory consumption is concerned, I used the
> Massif
> > tool from Valgrind.
>
> Matteo,
> thanks for clarifying. It would still be really nice if you could create a
> small program that really just builds a mesh, a DoFhandler, and then the
> sparsity pattern with both ways -- this would make it easier for us to
> figure
> out what is going on!
>
> Best
> W.
>
>
> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth email: [email protected]
> www: http://www.math.colostate.edu/~bangerth/
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