+float:detection_score_T_1 ... float:detection_score_T_L
+---------------------------- snip snip -------------------------------
+
+The method MTPTracker::write_trajectories writes first the number of
+trajectories, followed by one line per trajectory with the following
+structure
+
+---------------------------- snip snip -------------------------------
+int:traj_number int:entrance_time int:duration float:score int:location_1 ... int:location_duration