fix SparseType.may_share_memory with 2 sparse inputs.

theano/sparse/basic.py

@@ -437,7 +437,9 @@ class SparseType(gof.Type):
         # This is Fred suggestion for a quick and dirty way of checking
         # aliasing .. this can potentially be further refined (ticket #374)
         if _is_sparse(a) and _is_sparse(b):
-            return a is b
+            return (SparseType.may_share_memory(a, b.data) or
+                    SparseType.may_share_memory(a, b.indices) or
+                    SparseType.may_share_memory(a, b.indptr))
         if _is_sparse(b) and isinstance(a, numpy.ndarray):
             a, b = b, a
         if _is_sparse(a) and isinstance(b, numpy.ndarray):

theano/sparse/tests/test_basic.py

@@ -1323,6 +1323,10 @@ def test_may_share_memory():
                         (b.indptr, a, False),
                         (b.indices, a, False),
                         (as_ar(b.shape), a, False),
+                        (a.transpose(), a, True),
+                        (b.transpose(), b, True),
+                        (a.transpose(), b, False),
+                        (b.transpose(), a, False),
                         ]:
 
         assert SparseType.may_share_memory(a_, b_) == rep