Dear Bruno,
Thank you very much for your help.
I would kindly like to ask what is the recommended way in Dealii to write
on a plain .txt file the results of a single point when using MPI. I solve
for different frequencies and would like to write the solution after each
iteration. In the non-parallel version it works as follows:
*ofstream myfile;*
* myfile.open ("solution.txt");*
* for ( int freq = 0; freí< 10; ++i)*
* {*
* setup_system();*
* assemble_system(freq);*
* solve();*
* output_results(myfile);*
* }*
* myfile.close();*
The function *output_results(myfile) *takes care of writing the
solution of a single point in a plain .txt file for each frequency.
Step-40 shows a way to write .vtu files format when using MPI, but I did
not find any function to write the plain solution.
I would appreciate any suggestions on how to do that using Dealii.
Thank you again.
Regards,
H.
El jue, 9 sept 2021 a las 14:36, Bruno Turcksin (<[email protected]>)
escribió:
> Hermes,
>
> The following line is wrong:
> *DynamicSparsityPattern dsp(locally_relevant_dofs.n_elements(),
> locally_relevant_dofs.n_elements());*
>
> This constructor says that you want a sparsity pattern that has
> *locally_relevant_dofs.n_elements()
> *elements. This is not the case. You want a sparsity pattern that has as
> many elements as the total numbers of dofs. Also since you want to use MPI,
> you need to provide a third argument, the locally_owned IndexSet.
>
> You can also simply use:
> *DynamicSparsityPattern dsp(locally_relevant_dofs);*
>
> Best,
>
> Bruno
>
> On Thursday, September 9, 2021 at 5:29:56 AM UTC-4 [email protected]
> wrote:
>
>> Dear all,
>>
>> I adapted step-29 to run in parallel, similar as step-40. With 1 MPI rank
>> it works, however, when using more than 1 rank I get a running error
>> (attached is the full output)
>>
>> *An error occurred in line <74> of file
>> </var/folders/8z/hlb6vc015qjggytkxn84m6_c0000gn/T/heltai/spack-stage/spack-stage-dealii-9.3.0-zy7k3uwnakcqjvrajvacy5l4jrl7eaex/spack-src/source/dofs/dof_tools_sparsity.cc>
>> in function*
>>
>> * void dealii::DoFTools::make_sparsity_pattern(const DoFHandler<dim,
>> spacedim> &, SparsityPatternType &, const AffineConstraints<number> &,
>> const bool, const types::subdomain_id) [dim = 2, spacedim = 2,
>> SparsityPatternType = dealii::DynamicSparsityPattern, number = double]*
>>
>> *The violated condition was: *
>>
>> * sparsity.n_rows() == n_dofs*
>>
>> *Additional information: *
>>
>> * Dimension 26752 not equal to 51842*
>>
>> I found out that the problem is in the setp_system() function. The
>> problematic line is in red. Could you please help me to figure out the
>> issue?
>>
>>
>> *template <int dim>*
>>
>> * void UltrasoundProblem<dim>::setup_system()** {*
>>
>> * deallog << "Setting up system... ";*
>>
>> * deallog << "OK1... ";*
>>
>> * dof_handler.distribute_dofs(fe);*
>>
>> * locally_owned_dofs = dof_handler.locally_owned_dofs();*
>>
>> * DoFTools::extract_locally_relevant_dofs(dof_handler,
>> locally_relevant_dofs);*
>>
>> * locally_relevant_solution.reinit(locally_owned_dofs, *
>> *locally_relevant_dofs,**mpi_communicator);*
>>
>> * system_rhs.reinit(locally_owned_dofs, mpi_communicator);*
>>
>> * constraints.clear();*
>>
>> * constraints.reinit(locally_relevant_dofs);*
>>
>> * DoFTools::make_hanging_node_constraints(dof_handler, constraints);*
>>
>> * VectorTools::interpolate_boundary_values(dof_handler,** 1,*
>> *DirichletBoundaryValues<dim>(),**constraints);*
>>
>> * constraints.close();*
>>
>> * DynamicSparsityPattern dsp(locally_relevant_dofs.n_elements(),
>> locally_relevant_dofs.n_elements());*
>>
>> * DoFTools::make_sparsity_pattern(dof_handler,
>> dsp,constraints,false);//THIS*
>>
>>
>> *
>> SparsityTools::distribute_sparsity_pattern(dsp,dof_handler.locally_owned_dofs(),mpi_communicator,locally_relevant_dofs);*
>>
>> * system_matrix.reinit(locally_owned_dofs,locally_owned_dofs, dsp,
>> mpi_communicator);*
>>
>> * }*
>>
>>
>> Thank you very much
>>
>> H.
>>
>>
>>
>> --
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