This is the last step in order to read a simulation done with MPI. Here I am simply using the index files to compute the number of particles at a given time and implement an exit condition when trying to read a particle that was removed.
As the default hydro scheme changed, I have also implemented SPHENIX. @jborrow feel free to comment about SPHENIX (files src/hydro/SPHENIX/* and logger/hydro/SPHENIX/*).