Dear all,
I want to compute the L2-norm for a large number of scalar
history-variables. The solution vectors for all of them are stored in the
following container:
"std::vector<Vector<double>>(num_of_history_variables)".
So far I called integrate_difference " num_of_history_variables" times,
which is quite time consuming. Thus, I´d like to compute the L2-norm by
myself to get a second time measurement and may save in the first call some
time reducing information which integrate_differnce doesn´t provide for
subsequent calls.
In order to do so, I compared for a arbitrary history variable the vector
of cell errors, calculated from integrate_differnce, with those cell errors
of my own implementation. Unfortunately I don´t come up with the same cell
error(s).
In the following is a snippet of my code, some remarks for a better
understanding:
(I access my history variables via a CellDataStorage object. The Variable
"comp_0" is the value at the QP of my current mesh, the variable
"comp_0_ref" is the corresponding value of the reference solution on the
same QP).
------------------------------------------------------------------------------------------------
Functions::FEFieldFunction<dim> fe_field(dof_handler_scalar_ar,
reference_solution_n[0]);
cell=dof_handler_scalar.begin_active();
for(; cell!=endc; cell++)
{
fe_values.reinit(cell);
std::vector<std::shared_ptr<PointHistory<dim>>> lqph =
quadrature_point_history.get_data(cell);
double error_cell=0;
for(unsigned int q=0; q<qf_cell.size(); q++)
{
const double JxW = fe_values.JxW(q);
Vector<double> projection_variables =
lqph[q]->create_vector_for_projection();
double comp_0 = projection_variables(0);
error_cell += ((comp_0 - comp_0_ref)*(comp_0 - comp_0_ref)*JxW);
}
std::cout<<"Local cell error: "<<std::sqrt(error_cell)<<" , ";
}
------------------------------------------------------------------------------------------
I had a look in the implementation of the integrate_difference function
with case == L2 as well.
However I could not identify any differences to my own implementation.
My question is if there is a mistake in my code snippet, i.e in the way how
I calculate the integrals for the cell errors?
On each cell, I basically multiply the squared abs-value of the difference
with the JxW-Value, sum those values up and finally take the square root.
Thanks in advance for helping!
Best
Simon
--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see
https://groups.google.com/d/forum/dealii?hl=en
---
You received this message because you are subscribed to the Google Groups
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/dealii/8223cc52-415b-4b5b-9a06-c016570515dbn%40googlegroups.com.
