choose another refant if no stations left after filtering

Former-commit-id: f535b982
Former-commit-id: c2d23fb3

steps/findRefAnt_join.cwl

@@ -46,14 +46,21 @@ requirements:
             with open('input.json', 'r') as f_stream:
                 flagged_fraction_dict_list = json.load(f_stream)
             filter_station = '$(inputs.filter_station)'
+            no_station_selected = True
     
+            while no_station_selected:
+                print('Applying station filter ' + str(filter_station))
                 flagged_fraction_data = {}
+                no_station_selected = False
                 for flagged_fraction_dict in flagged_fraction_dict_list:
                     entry = ast.literal_eval(flagged_fraction_dict)
                     antennas = entry.keys()
                     selected_stations = [ station_name for station_name in antennas if re.match(filter_station, station_name) ]
                     if len(selected_stations) == 0:
-                    raiseError('No stations left after filtering.')
+                        print('No stations left after filtering. Station(s) do(es) not exist in all subbands. No filter is used.')
+                        filter_station = ''
+                        no_station_selected = True
+                        break
                     for antenna in selected_stations:
                         try:
                             flagged_fraction_data[antenna].append(float(entry[antenna]))