Changed docstring for subtensor optimization

theano/tensor/opt.py

@@ -2181,10 +2181,13 @@ def local_subtensor_of_alloc(node):
 @gof.local_optimizer([Subtensor])
 def local_subtensor_of_dot(node):
     """
-    This optimization translates T.dot(A, B)[idxs] into T.dot(A[idxs_a], B[idxs_b]).
-    idxs_a is the first A.ndim-1 entries of idxs
-    idxs_b is the remaining entries of idxs (if any), 
-    but with : inserted in the second-to-last dimension (because dot sums over this dimension)
+    This optimization translates T.dot(A, B)[idxs] into T.dot(A[idxs_a], B[idxs_b]),
+    where idxs_a and idxs_b are defined appropriately.
+
+    idxs_a is the first A.ndim-1 entries of idxs,
+    and idxs_b is the remaining entries of idxs (if any),
+    modified to skip the second-to-last dimension of B
+    (because dot sums over this dimension)
     """
     if not isinstance(node.op, Subtensor):
         return