Merge branch 'nouiz-error'

theano/configdefaults.py

@@ -136,9 +136,13 @@ AddConfigVar('nocleanup',
         BoolParam(False),
         in_c_key=False)
 
+# This flag is used when we import Theano to initialize global variables.
+# So changing it after import will not modify these global variables.
+# This could be done differently... but for now we simply prevent it from being
+# changed at runtime.
 AddConfigVar('tensor.cmp_sloppy',
         "Relax tensor._allclose (0) not at all, (1) a bit, (2) more",
-        IntParam(0, lambda i: i in (0,1,2)),
+        IntParam(0, lambda i: i in (0,1,2), allow_override=False),
         in_c_key=False)
 
 AddConfigVar('tensor.local_elemwise_fusion',

theano/tensor/basic.py

@@ -1222,12 +1222,16 @@ class _tensor_py_operators:
     shape = property(lambda self: shape(self))
     size = property(lambda self: prod(self.shape))
 
-    def __len__(self):
-        # We can't implement __len__ as Python requests that this
-        # function returns an integer >=0
-        raise TypeError("Theano Variables can't work with len(Theano "
-                        "Variable) due to Python restriction. You can use "
-                        "TheanoVariable.shape[0] instead.")
+    # We can't implement __len__ to provide a better error message.
+    # Otherwise TensorVariable[:-1] does not work as Python 2.5.1 calls
+    # __len__ before calling __getitem__. It also does not catch the raised
+    # Exception!
+#     def __len__(self):
+#         # We can't implement __len__ as Python requests that this
+#         # function returns an integer >=0
+#         raise Exception("Theano Variables can't work with len(Theano "
+#                         "Variable) due to Python restriction. You can use "
+#                         "TheanoVariable.shape[0] instead.")
 
     def reshape(self, shape, ndim=None):
         """Return a reshaped view/copy of this variable.