All good, I am just not sure what you mean by parallelization as batches of placements, is this batches of LOO tasks grouped together or do you want to further parallelize each LOO task by conducting simulatenous placements into different branches, the latter is implemented in EPA-NG anyway, so I would opt for parallelizing over LOOs, but assign more than one core to each LOO task such that it can profit from EPA-NG's internal parallelization that parallelizes over placements