Bugfix: allow two detectors exactly in offline search (gwastro#4464)

* bugfix for skipping exclude_zerolag in two-detector-exactly search

* Allow the search to use two-detectors exactly

* clarify why a job is removed in the exact-coincidence case

bin/workflows/pycbc_make_offline_search_workflow

@@ -278,20 +278,29 @@ for ifocomb in ifo_sets:
     else:
         ordered_ifo_list = ifocomb[0]
         coinctag= '1det'
-    other_ifo_keys = list(no_fg_exc_files.keys())
-    other_ifo_keys.remove(ordered_ifo_list)
-    ctagcomb = ['full_data', coinctag]
-    other_bg_files = {ctype: no_fg_exc_files[ctype]
-                      for ctype in other_ifo_keys}
-    final_bg_files[ordered_ifo_list] = wf.setup_exclude_zerolag(
-        workflow,
-        no_fg_exc_files[ordered_ifo_list],
-        wf.FileList(other_bg_files.values()),
-        output_dir, ordered_ifo_list,
-        tags=ctagcomb
-    )
 
-combined_bg_file = wf.setup_combine_statmap(
+    if len(ifo_sets) == 1:
+        # Just one event type - pass it through
+        final_bg_files[ordered_ifo_list] = no_fg_exc_files[ordered_ifo_list]
+    else:
+        # Combining the statmap files, multiple possible event types
+        other_ifo_keys = list(no_fg_exc_files.keys())
+        other_ifo_keys.remove(ordered_ifo_list)
+        ctagcomb = ['full_data', coinctag]
+        other_bg_files = {ctype: no_fg_exc_files[ctype]
+                          for ctype in other_ifo_keys}
+        final_bg_files[ordered_ifo_list] = wf.setup_exclude_zerolag(
+            workflow,
+            no_fg_exc_files[ordered_ifo_list],
+            wf.FileList(other_bg_files.values()),
+            output_dir, ordered_ifo_list,
+            tags=ctagcomb
+        )
+
+if len(ifo_sets) == 1:
+    combined_bg_file = no_fg_exc_files[ordered_ifo_list]
+else:
+    combined_bg_file = wf.setup_combine_statmap(
                                 workflow,
                                 wf.FileList(final_bg_files.values()),
                                 wf.FileList([]),
@@ -457,6 +466,7 @@ ifar_ob = wf.make_ifar_plot(workflow, combined_bg_file,
                                     rdir['open_box_result'],
                                     tags=combined_bg_file.tags + ['open_box'],
                                     executable='page_ifar_catalog')
+
 table = wf.make_foreground_table(workflow, combined_bg_file,
                                  hdfbank, rdir['open_box_result'],
                                  singles=insps, extension='.html',
@@ -523,9 +533,11 @@ for key in final_bg_files:
         closed_page = [(snrifar_cb, ifar_cb)]
     else:
         closed_page = [(snrifar_cb,)]
-    table = wf.make_foreground_table(workflow, bg_file, hdfbank, open_dir,
-                                     singles=insps, extension='.html',
-                                     tags=bg_file.tags)
+    if len(ifo_sets) > 1:
+        # If there is only one ifo_set, then this table has already been made
+        table = wf.make_foreground_table(workflow, bg_file, hdfbank, open_dir,
+                                         singles=insps, extension='.html',
+                                         tags=bg_file.tags)
 
     detailed_page = [(snrifar, ratehist), (snrifar_ifar, ifar_ob), (table,)]
     layout.two_column_layout(open_dir, detailed_page)