Refs #8528. Allow reducing multi slices from event workspaces

Code/Mantid/scripts/SANS/ISISCommandInterface.py

@@ -638,23 +638,49 @@ def _applySuffix(result, name_suffix):
             RenameWorkspace(InputWorkspace=old,OutputWorkspace= result)
         return result
 
+    def _common_substring(val1, val2):
+        l = []
+        for i in range(len(val1)):
+            if val1[i]==val2[i]: l.append(val1[i])
+            else:
+                return ''.join(l)
+
+    def _group_workspaces(list_of_values, outputname):
+        allnames = ','.join(list_of_values)
+        GroupWorkspaces(InputWorkspaces=allnames, OutputWorkspace=outputname)
+
+    def _reduceAllSlices():
+        if ReductionSingleton().getNumSlices() > 1:
+            slices = []
+            for index in range(ReductionSingleton().getNumSlices()):
+                ReductionSingleton().setSliceIndex(index)
+                slices.append(ReductionSingleton()._reduce())
+            ReductionSingleton().setSliceIndex(0)
+            group_name = _common_substring(slices[0], slices[1])
+            if group_name[-2] == "_":
+                group_name = group_name[:-2]
+            _group_workspaces(slices, group_name)
+            return group_name
+        else:
+            return ReductionSingleton()._reduce()
+
+
 
     result = ""
     if ReductionSingleton().get_sample().loader.periods_in_file == 1:
-        result = ReductionSingleton()._reduce()
+        result = _reduceAllSlices()
         return _applySuffix(result, name_suffix)
 
     calculated = []
     try:
         for period in ReductionSingleton().get_sample().loader.entries:
             _setUpPeriod(period)
-            calculated.append(ReductionSingleton()._reduce())
+            calculated.append(_reduceAllSlices())                
 
     finally:
         if len(calculated) > 0:
-            allnames = ','.join(calculated)
             result = ReductionSingleton().get_out_ws_name(show_period=False)
-            GroupWorkspaces(OutputWorkspace=result, InputWorkspaces=allnames)
+            _group_workspaces(calculated, result)
 
     return _applySuffix(result, name_suffix)