Store alive attribute for PhaseSpaceMonitor class

tracking/monitors.py

@@ -311,8 +311,10 @@ class PhaseSpaceMonitor(Monitor):
         self.bunch_number = bunch_number
         self.mp_number = int(mp_number)
         group_name = "PhaseSpaceData_" + str(self.bunch_number)
-        dict_buffer = {"particles":(self.mp_number, 6, buffer_size)}
-        dict_file = {"particles":(self.mp_number, 6, total_size)}
+        dict_buffer = {"particles":(self.mp_number, 6, buffer_size), 
+                       "alive":(self.mp_number, buffer_size)}
+        dict_file = {"particles":(self.mp_number, 6, total_size),
+                     "alive":(self.mp_number, total_size)}
         self.monitor_init(group_name, save_every, buffer_size, total_size,
                           dict_buffer, dict_file, file_name, mpi_mode)