Fix Particle ID creation
Currently the nextID variable in the particle IDs creation is updated in the following way
nextID_m += numNodes_m * (nLocal - localNum_m);
This has a problem when localNum_m > nLocal
as it can lead to negative particle IDs. I think if we just do
nextID_m += numNodes_m * nLocal
it solves the issue and the IDs are still unique