Added tensor.angle() function, which is just raising NotImplementedError

theano/tensor/basic.py

@@ -1628,6 +1628,11 @@ def imag(x):
     else:
         return zeros_like(x)
 
+@constructor
+def angle(x):
+    """Return the angular component of complex-valued `x`"""
+    raise NotImplementedError()
+
 
 ##########################
 # Misc