How to deal with this Error: Unable to access vector of degree of freedom?

Hi everybody!

I’ve got a code that runs in serial without any problem. However, I want a much higher resolution. When I tried a finer mesh, I ran out of memory. So I implemented the parallel version of the code and got the following error (This is the first time I see an error of this sort and I’m pretty sure about my parallel implementation!). Has anybody run into a similar problem or knows how to address this?

image

PS: The error points to a line in my code which reads:

with XDMFFile(mesh.mpi_comm(),‘SIO/Q.xdmf’) as file:
file.read_checkpoint(f,‘Source’,0)

Many thanks in advance!