Hello,
thank You for response and the advices.
>> LA::Vector<double> vec_old_solution(dof_handler_nse.n_dofs());
>>
>> VectorTools::interpolate(dof_handler_nse, ZeroFunction<3>(dim +
1),
>> vec_old_solution);
>>
>> old_solution_nse = vec_old_solution;
>
> > Are you using a serial vector here, interpolate a zero function, and
> > then copy it over? That will be slow of course. You could just write
> > "old_solution_nse=0" instead.
>
It doesnt take such a long time, but I will try it, see below
> It would also be helpful to know, which part of your setup is slow.
> > You can find out by adding more timing sections.
>
I have added timing subsections:
computing_timer.enter_subsection("Setup NS");
computing_timer.enter_subsection("NS renumbering");
dof_handler_nse.distribute_dofs(fe_nse);
DoFRenumbering::Cuthill_McKee(dof_handler_nse);
computing_timer.leave_subsection();
locally_owned_dofs_nse = dof_handler_nse.locally_owned_dofs();
DoFTools::extract_locally_relevant_dofs(dof_handler_nse,
locally_relevant_dofs_nse);
locally_relevant_solution_nse.reinit(locally_owned_dofs_nse,
locally_relevant_dofs_nse, mpi_communicator);
old_solution_nse.reinit(locally_owned_dofs_nse,
locally_relevant_dofs_nse, mpi_communicator);
old_solution_nse = 0;
solution_nse.reinit(locally_owned_dofs_nse,
locally_relevant_dofs_nse,
mpi_communicator);
system_rhs_nse.reinit(locally_owned_dofs_nse, mpi_communicator);
system_rhs_nse = 0;
computing_timer.enter_subsection("constraint matrix preparation");
constraint_matrix_nse.clear();
constraint_matrix_nse.reinit(locally_relevant_dofs_nse);
DoFTools::make_hanging_node_constraints(dof_handler_nse,
constraint_matrix_nse);
std::vector<bool> component_mask(dim + 1, false);
for (int i = 0; i < dim; ++i)
component_mask[i] = true; // velocities
VectorTools::interpolate_boundary_values(dof_handler_nse, 0,
ConstantFunction<dim>(0., dim + 1),
constraint_matrix_nse,
component_mask);
VectorTools::interpolate_boundary_values(dof_handler_nse, 1,
InflowVelocityBoundaryValues<dim>(),
constraint_matrix_nse,
component_mask);
constraint_matrix_nse.close();
computing_timer.leave_subsection();
computing_timer.enter_subsection("interpolation zero nse solution");
LA::Vector<double> vec_old_solution(dof_handler_nse.n_dofs());
VectorTools::interpolate(dof_handler_nse, ZeroFunction<3>(dim +
1),
vec_old_solution);
old_solution_nse = vec_old_solution;
computing_timer.leave_subsection();
computing_timer.enter_subsection("making sparsity pattern");
DynamicSparsityPattern csp(locally_relevant_dofs_nse);
DoFTools::make_sparsity_pattern(dof_handler_nse, csp,
constraint_matrix_nse, false);
SparsityTools::distribute_sparsity_pattern(csp,
dof_handler_nse.n_locally_owned_dofs_per_processor(),
mpi_communicator, locally_relevant_dofs_nse);
computing_timer.leave_subsection();
computing_timer.enter_subsection("reinit of system matrix");
system_matrix_nse.reinit(locally_owned_dofs_nse,
locally_owned_dofs_nse,
csp, mpi_communicator);
computing_timer.leave_subsection();
computing_timer.leave_subsection();
The Navier-Stokes system has ~47000 dofs
I have compiled it in release mode, I ran it on 4-cores
Results from the log:
constraint matrix preparation, wall time: *6.41976s.*
interpolation zero nse solution, wall time: 0.00220919s.
making sparsity pattern, wall time: 0.0638468s.
reinit of system matrix, wall time: 0.222504s.
Setup NS, wall time: 7.57601s.
Setup, wall time: 7.72225s. (together with Cahn-Hilliard system
setting)
So, apparently the constraint matrix preparation is dominant.
Maybe I am doing something wrong
I will try to prepare some comparison with Step-40, Step-33 as you proposed.
Thank You
Marek
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