changed index substitution optim

isation

Author: achanbour

gem/optimise.py

@@ -102,12 +102,14 @@ def _replace_indices_atomic(i, self, subst):
         return i if new_expr == i.expression else VariableIndex(new_expr)
     else:
         substitute = dict(subst)
-        if isinstance(i, ListIndex) and i.free_index in substitute:
-            replacement = substitute[i.free_index]
-            if isinstance(replacement, int):
-                return int(i.index_array[replacement]) 
-            return ListIndex(i.index_array, free_index=substitute[i.free_index])
-        return substitute.get(i,i)
+        def _replace(i):
+            if isinstance(i, ListIndex) and i.free_index in substitute:
+                replacement = substitute[i.free_index]
+                if isinstance(replacement, int):
+                    return int(i.index_array[replacement]) 
+                return ListIndex(i.index_array, free_index=substitute[i.free_index])
+            return substitute.get(i,i)
+        return _replace(i)
 
 
 @replace_indices.register(Delta)