Propagate the allow_gc flag in scan optimizations.

theano/scan_module/scan.py

@@ -967,6 +967,8 @@ def scan(fn,
     ##
 
     tap_array = mit_sot_tap_array + [[-1] for x in xrange(n_sit_sot)]
+    if allow_gc is None:
+        allow_gc = config.scan.allow_gc
     info = OrderedDict()
 
     info['tap_array'] = tap_array
@@ -985,8 +987,9 @@ def scan(fn,
     info['gpu'] = False
     info['as_while'] = as_while
     info['profile'] = profile
+    info['allow_gc'] = allow_gc
 
-    local_op = scan_op.Scan(inner_inputs, new_outs, info, allow_gc=allow_gc)
+    local_op = scan_op.Scan(inner_inputs, new_outs, info)
 
     ##
     ### Step 8. Compute the outputs using the scan op

theano/scan_module/scan_op.py

@@ -49,7 +49,6 @@ class Scan(PureOp):
                  inputs,
                  outputs,
                  info,
-                 allow_gc=None
                 ):
         """
         :param inputs: inputs of the inner function of scan
@@ -58,13 +57,9 @@ class Scan(PureOp):
             the scan op (like number of different types of
             arguments, name, mode, if it should run on GPU or
             not, etc.)
-        :param allow_gc: Use the gc in the inner function or not
-            (independant of the outer function)
         """
         if 'gpua' not in info:
             info['gpua'] = False
-        if allow_gc is None:
-            allow_gc = config.scan.allow_gc
         # adding properties into self
         self.inputs = inputs
         self.outputs = outputs
@@ -73,7 +68,6 @@ class Scan(PureOp):
         # since info contains all tunable parameters of the op, so for two
         # scan to be equal this tunable parameters should be the same
         self.info = info
-
         # build a list of output types for any Apply node using this op.
         self.output_types = []
         idx = 0
@@ -111,7 +105,7 @@ class Scan(PureOp):
             isinstance(mode_instance, compile.profilemode.ProfileMode)):
             mode_instance = compile.profilemode.ProfileMode(
                 optimizer=mode_instance.provided_optimizer,
-                linker=mode_instance.linker.clone(allow_gc=allow_gc))
+                linker=mode_instance.linker.clone(allow_gc=self.allow_gc))
             compile.profilemode.prof_mode_instance_to_print.append(
                                                     mode_instance)
             self.mode_instance = mode_instance
@@ -122,7 +116,7 @@ class Scan(PureOp):
         else:
             self.mode_instance = type(mode_instance)(
                 optimizer=mode_instance.provided_optimizer,
-                linker=mode_instance.linker.clone(allow_gc=allow_gc))
+                linker=mode_instance.linker.clone(allow_gc=self.allow_gc))
 
         if not hasattr(self, 'name') or self.name is None:
             self.name = 'scan_fn'
@@ -456,15 +450,11 @@ class Scan(PureOp):
             if self_in.type != other_in.type:
                 return False
 
-        if not scan_utils.equal_computations(self.outputs,
+        return scan_utils.equal_computations(self.outputs,
                                              other.outputs,
                                              self.inputs,
-                                             other.inputs):
-            return False
+                                             other.inputs)
 
-        # If they do, then they need to match in other small details
-        # like name, mode, etc.
-        return True
 
     def __str__(self):
         if self.gpu:

theano/scan_module/scan_opt.py

@@ -1500,6 +1500,7 @@ class ScanMerge(gof.Optimizer):
         info['gpu'] = False
         info['as_while'] = as_while
         info['profile'] = nodes[0].op.profile
+        info['allow_gc'] = nodes[0].op.allow_gc
 
         # We keep the inner_ins and inner_outs of each original node separated.
         # To be able to recombine them in the right order after the clone,

theano/scan_module/scan_utils.py

@@ -654,9 +654,11 @@ def compress_outs(op, not_required, inputs):
     info['truncate_gradient'] = op.info['truncate_gradient']
     info['name'] = op.info['name']
     info['gpu'] = op.info['gpu']
+    info['gpua'] = op.info['gpua']
     info['mode'] = op.info['mode']
     info['as_while'] = op.info['as_while']
     info['profile'] = op.info['profile']
+    info['allow_gc'] = op.info['allow_gc']
 
     op_inputs = op.inputs[:op.n_seqs]
     op_outputs = []
@@ -919,7 +921,7 @@ class scan_args(object):
 
         self.other_info = OrderedDict()
         for k in ('truncate_gradient', 'name', 'mode', 'destroy_map',
-                  'gpu', 'as_while', 'profile'):
+                  'gpu', 'gpua', 'as_while', 'profile', 'allow_gc'):
             if k in info:
                 self.other_info[k] = info[k]