Sort HLT and L1 histogram x-axes alphabetically

This addresses issues discussed in [ATR-21172] and [ATR-19976] by alphabetically sorting the x-axes of the histograms monitoring L1 items and HLT chains.
Currently, the histograms monitoring L1 items and HLT chains which are fired in the run, are filled in the order the events happen to be processed. This means that the shape of the histograms can differ quite dramatically for reasons purely to do with process ordering, which is clearly not the desired behaviour.

After the change, we will have these improvements:

• Reprocessing the same run without changing the menu will result in an identical histogram.
• If the menu is changed (by removing or adding a few chains) the x-axis will shift a little bit in a way which is clearly recognisable.
• All histograms from a particular signature will end up together. (With the exception of multi-ele/jet/muon/etc where HLT_2jX_blabla will be closer to HLT_2eX_blabla than to HLT_jX_blabla )

Example of desired behaviour (Run 2 code): https://atlas.web.cern.ch/Atlas/project/trigger/trigcaf/www/ATR-24194-legacy/ResultMon/L1Events.html
What is currently looks like in Run 3 code: https://atlas.web.cern.ch/Atlas/project/trigger/trigcaf/www/ATR-24194-run3/ResultMon/L1Events.html (data and reference disagree artificially even though there was no change).

CC: @astruebi , @palacino

Trigger/TrigMonitoring/TrigHLTMonitoring/python/TrigGeneralMonitorAlgorithm.py

@@ -37,10 +37,6 @@ def TrigGeneralMonConfig(inputFlags):
     trigHLTMonAlg.TrigConfigSvc = cfgsvc
 
 
-
-    # Edit properties of a algorithm
-    # 
-
     ####### Signature names 
 
     signature_names = []
@@ -53,7 +49,7 @@ def TrigGeneralMonConfig(inputFlags):
     signature_names.append("Jets") #6
     signature_names.append("MinBias") #7
   
-    # Add a monitoring tool per signature (a "group" in old language). 
+
     hltGroup = helper.addGroup(
         trigHLTMonAlg,
         'TrigHLTMonitor',
@@ -116,35 +112,47 @@ def TrigGeneralMonConfig(inputFlags):
 
     from AthenaConfiguration.AutoConfigFlags import GetFileMD
 
-    ### Set up counters ########################################
 
+    ########################
     ## The HLT chains
-    counter_i = 1
+    HLT_names_AllChains = []
+    log_trighlt.debug('HLT chains:')
     for chain_name in GetFileMD(inputFlags.Input.Files)['TriggerMenu']['HLTChains']:
-        counter_i = counter_i+1
-        log_trighlt.debug('HLT chain_name = %s',chain_name) 
-    max_hlt_chains = counter_i-1
+        log_trighlt.debug('HLT chain_name = %s',chain_name)
+        HLT_names_AllChains.append(chain_name)
+    max_hlt_chains = len(HLT_names_AllChains)
     log_trighlt.debug('max_hlt_chains = %i', max_hlt_chains) 
 
 
+    #Sort HLT names alphabetically, to make the HLT histograms have the same 
+    #x axes for different runs and reprocessings
+    HLT_names_AllChains_sorted = sorted(HLT_names_AllChains)
+
+
+
+    #########################
     ## The L1 items
-    counter_L1 = 1
+    L1_names =[]
     for item_name in GetFileMD(inputFlags.Input.Files)['TriggerMenu']['L1Items']:
-        counter_L1 = counter_L1+1
         log_trighlt.debug('L1 item_name = %s',item_name) 
-    max_L1_items = counter_L1-1 
+        L1_names.append(item_name)
+    max_L1_items = len(L1_names)
     log_trighlt.debug('max_L1_items = %i', max_L1_items) 
 
+    #Sort L1 names alphabetically, to make the L1 histograms have the same 
+    #x axes for different runs and reprocessings
+    L1_names_sorted = sorted(L1_names)
 
     ##### L1 summary histogram ################################
 
     hltGroup.defineHistogram('L1Events',title='Events per Item at L1;;Events',
-                             path='',xbins=max_L1_items,xmin=1,xmax=max_L1_items+1)
-
+                             path='',xbins=len(L1_names_sorted), xmin=0, 
+                             xmax=len(L1_names_sorted), xlabels=L1_names_sorted)
 
     #### HLT summary histograms for the signatures #############
 
     triggerstatus = ['RAW','PS'] #all chains or prescaled chains
+
     for sig in signature_names: #loop over signatures
         log_trighlt.debug("Signature %s",sig)
 
@@ -154,8 +162,9 @@ def TrigGeneralMonConfig(inputFlags):
             histname = "HLT_"+sig+trigstatus
             log_trighlt.debug('Histname = %s', histname)
             hltGroup.defineHistogram(histname,title=titlename,
-                                     path=sig,xbins=max_hlt_chains+1,
-                                     xmin=1,xmax=max_hlt_chains+1)
+                                     path=sig,xbins=len(HLT_names_AllChains_sorted),
+                                     xmin=0,xmax=len(HLT_names_AllChains_sorted), 
+                                     xlabels=HLT_names_AllChains_sorted)
 
  
     ### RoIs, one per signature