WCSim Validation

ba0178d92b27e6518e6925fab1df5fe6f04e64c6

Pull Request #512: Working build with optional hepmc3

SK_5MeVem_centre_xdir

Tests
156.71 sec
wcsimrootevent plot pass
wcsimrootevent2 plot pass
wcsimrootevent_OD plot pass
Geom pass
bad pass
Geometry warnings pass