Dear all,
after some time I came back to this problem again. I would kindly ask for
some guidance to see if I can understand and solve the issue.
I am using a parallel::distributed::Triangulation with MPI. I call the
function solve() in a loop for different frequencies and want to export the
solution of the whole domain for each frequency.
The code looks like:
*for ( int i= f0; i < fend; ++i)*
*{*
*....*
*solve(); // solve a frequency*
*testvec=locally_relevant_solution; //extract the solution*
*// DataOut *
*DataOut<dim> data_out;*
*data_out.attach_dof_handler(dof_handler);*
*string f_output("sol_" + std::to_string(i) + ".txt");*
*std::ofstream outloop(f_output);*
*testvec.print(outloop,9,true,false); // Save txt file with solution for 1
frequency.*
*}*
The way of extracting and exporting the solution with
*testvec=locally_relevant_solution * is a bad practice? I am saving the
locally relevant solution from many different processes in one single file
for a given frequency. I am afraid that there is no synchronization between
processes and the results will be saved without following the right order
of DOF (which is needed for me). Is this statement correct?
In that case, what would be the better way to export my domain for each
frequency?
Another issue that I found is that this approach increases dramatically the
computational time of the run() function. For a particular case, solving
the domain takes 1h without exporting the domain, while it takes 8h adding
the previous piece of code to export the domain. Is this because the print
function is slow or there is some sync going on when calling
*testvec=locally_relevant_solution?*
I would really appreciate if you can clarify and guide mee to solve this
issue.
Thank you very much
Regards
El jueves, 17 de febrero de 2022 a las 19:02:07 UTC+1, Wolfgang Bangerth
escribió:
> On 2/17/22 09:22, Uclus Heis wrote:
> >
> > I still had problems as I first copy the array and then I store it in a
> matrix
> > for diffeerent frequencies.The result I got was differet whene using few
> > process compared to using 1 single process. I added the following code
> and now
> > works, is it right?
>
> It copies a vector into a row of a matrix. Whether that's what you want is
> a
> different question, so we can't tell you whether it's "right" :-)
>
> You can simplify this by saying
> tmparray = locally_relevant_solution;
>
> Best
> W.
>
>
> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth email: [email protected]
> www: http://www.math.colostate.edu/~bangerth/
>
>
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