Fixed the hash function such that two ops have same hash when they compare

theano/scan_module/scan_op.py

@@ -214,6 +214,9 @@ class Scan(Op):
                                     self.n_shared_outs )
         self.n_outs = self.n_mit_mot + self.n_mit_sot + self.n_sit_sot
         self.n_tap_outs = self.n_mit_mot + self.n_mit_sot
+        self._cmodule_key = gof.CLinker.cmodule_key_(self.fn.maker.env,[])
+        self._hash_inner_graph = hash(self._cmodule_key)
+
 
     def make_node(self, *inputs):
         assert numpy.all(isinstance(i, gof.Variable) for i in inputs)
@@ -321,19 +324,27 @@ class Scan(Op):
         return apply_node
 
     def __eq__(self, other):
+        # Check if we are dealing with same type of objects
         if not type(self) == type(other):
             return False
+        # This are some safety checks ( namely that the inner graph has the
+        # same number of inputs and same number of outputs )
         elif not len(self.inputs) == len(other.inputs):
             return False
         elif not len(self.outputs) == len(other.outputs):
             return False
         else:
+            # If everything went OK up to here, there is still one thing to
+            # check. Namely, do the internal graph represent same
+            # computations
             for x,y in zip(self.inputs, other.inputs):
                 if not scan_utils.equal_computations(x,y):
                     return False
             for x,y in zip(self.outputs, other.outputs):
                 if not scan_utils.equal_computations(x,y):
                     return False
+            # If they do, then they need to match in other small details
+            # like name, mode, etc.
             return self.info == other.info
 
     def __str__(self):
@@ -353,10 +364,10 @@ class Scan(Op):
 
 
     def __hash__(self):
-        # any two objects that *might* compare equal must hash equal.
-        # so we don't check the self.inputs and self.outputs here and it's
-        # ok.
         return ( hash(type(self)) ^
+                # and a hash representing the inner graph using the
+                # CLinker.cmodule_key_
+                self._hash_inner_graph ^
                 scan_utils.hash_listsDictsTuples(self.info) )