[fem-fenics] MPI parallelisation

[Eugenio Gianniti]

Dear all,

I am currently stuck in the implementation of the MPI parallelisation in 
fem-fenics. I wrote some code for the parallel assembly of matrices, but if I 
try to run the examples it crashes with DOLFIN internal errors even before this 
new code is executed. I quickly recall what I know about the issue:

  1. MPI in itself does not seem to be the cause, since running with mpirun -n 
1 everything works (basically I understand that DOLFIN internally checks the 
number of processes, not the MPI initialisation, to decide if it needs to “act 
parallel”);

  2. just to be sure, I ran the equivalent C++ implementations of these 
examples, and everything works fine in parallel, too;

  3. trying different examples (in Octave) leads to different errors, spread 
all around DOLFIN’s code base, sometimes even before the call to assemble;

  4. whilst different examples cause different errors, the same example leads 
always to the same error.

>From the information I could extract, my guess is that the issue may arise 
>from the dynamic loading of the Octave functions that reference DOLFIN code. 
>However, I do not know how to further troubleshoot the problem. So I wonder if 
>someone has already dealt with a similar issue and has any advice to share or 
>if someone more familiar with Octave’s internals can provide me with any 
>helpful insight.

Thanks,
Eugenio