Switched to reading the "initial particles".

For the efficiency measurements, where we use this capability at the
moment, the initial particles are the ones that we're really
interested in...

Author: krasznaa

io/src/read_particles.cpp

@@ -58,7 +58,7 @@ void read_particles(
                 particles,
                 get_absolute_path((std::filesystem::path(directory) /
                                    std::filesystem::path(get_event_filename(
-                                       event, "-particles_final.csv")))
+                                       event, "-particles_initial.csv")))
                                       .native()),
                 get_absolute_path((std::filesystem::path(directory) /
                                    std::filesystem::path(