Increase simulation efficiency
In OPAL-cyclotron the function
ParallelCyclotronTracker::deleteParticle has an
allreduce function call that consumes quite a lot of runtime. I have a simulation of the PSI Ring cyclotron that runs for 17 h where 7 h are just calls of this MPI-function. I think we sould add a
DELETE_PARTICLE_FREQ option to OPAL in order to reduce computational cost. The default behaviour should of course remain.