Bugfix: Collective Monitor was not declared as collective

Author: szymonlopaciuk

examples/000a_sps_tune_shift.py

@@ -64,7 +64,7 @@
 )
 
 # initialize a damper with 100 turns gain
-transverse_damper = xf.TransverseDamper(
+transverse_damper = xw.TransverseDamper(
     gain_x=2/100, gain_y=2/100,
     zeta_range=(-0.5*bucket_length, 0.5*bucket_length),
     num_slices=100,
@@ -73,7 +73,7 @@
 )
 
 # initialize a monitor for the average transverse positions
-monitor = xf.CollectiveMonitor(
+monitor = xw.CollectiveMonitor(
     base_file_name=f'sps_tune_shift',
     monitor_bunches=True,
     monitor_slices=False,

xwakes/beam_elements/collective_monitor.py

@@ -73,6 +73,8 @@ class CollectiveMonitor(ElementWithSlicer):
         Use flattened wakes
     """
 
+    iscollective = True
+
     _stats_to_store = [
         'mean_x', 'mean_px', 'mean_y', 'mean_py', 'mean_zeta',
         'mean_delta', 'sigma_x', 'sigma_y', 'sigma_zeta',