Make python backend work with mode=FAST_COMPILE

theano/scan_module/scan_op.py

@@ -1296,7 +1296,7 @@ class Scan(PureOp):
                 else:
                     old_input_data[idx] = None
 
-            # 5. compute outputs
+            # 5.0.1 compute outputs
             t0_fn = time.time()
 
             try:
@@ -1325,8 +1325,20 @@ class Scan(PureOp):
                 pdx = offset + self.n_shared_outs
                 cond = output_storage[pdx].storage[0] == 0
 
-            # Check which of the pre-allocated outputs (if applicable) have
-            # been reused by the inner function
+            # 5.0.2. By calling fn() directly instead of calling the theano
+            # function, it is possible that the updates have not been
+            # performed. Perform the updates if needed.
+            offset_out = len(output_storage) - 1
+            if getattr(fn, 'need_update_inputs', True):
+                # Update the inputs that have an update function
+                for inp, storage in zip(self.fn.maker.expanded_inputs,
+                                        self.fn.input_storage)[::-1]:
+                    if inp.update is not None:
+                        storage.data = output_storage[offset_out].data
+                        offset_out -= 1
+
+            # 5.0.3. Check which of the pre-allocated outputs (if applicable)
+            # have been reused by the inner function
             for idx in xrange(len(output_storage)):
                 # If the storage map does not contain the same object, then
                 # the pre-allocated output has not been reused
@@ -1348,8 +1360,8 @@ class Scan(PureOp):
                 else:
                     output_reused[idx] = False
 
-            # Check which of the input storage have been modified by the inner
-            # function
+            # 5.0.4 Check which of the input storage have been modified by the
+            # inner function
             for idx in xrange(len(input_storage)):
                 # If the storage map does not contain the same object, then
                 # the pre-allocated output has not been reused