tower specific noreuse scope

tensorpack/models/model_desc.py

@@ -39,6 +39,25 @@ class TowerContext(object):
     def is_training(self):
         return self._is_training
 
+    @property
+    def name(self):
+        return self._name
+
+    def get_variable_on_tower(self, *args, **kwargs):
+        """
+        Get a variable for this tower specifically, without reusing.
+        Tensorflow doesn't allow reuse=False scope under a
+        reuse=True scope. This method provides a work around.
+        See https://www.tensorflow.org/versions/master/how_tos/variable_scope/index.html#basics-of-tfvariable-scope
+
+        :param args, kwargs: same as tf.get_variable()
+        """
+        with tf.variable_scope(self._name) as scope:
+            with tf.variable_scope(scope, reuse=False):
+                scope = tf.get_variable_scope()
+                assert scope.reuse == False
+                return tf.get_variable(*args, **kwargs)
+
     def find_tensor_in_main_tower(self, graph, name):
         if self.is_main_tower:
             return graph.get_tensor_by_name(name)

tensorpack/train/trainer.py

@@ -46,8 +46,8 @@ class PredictorFactory(object):
         return OnlinePredictor(self.sess, raw_input_vars, output_vars)
 
     def _build_predict_tower(self):
-        # build_predict_tower might get called anywhere, but 'towerp' should be the outermost name scope
         tf.get_variable_scope().reuse_variables()
+        # build_predict_tower might get called anywhere, but 'towerp' should be the outermost name scope
         with tf.name_scope(None), \
                 freeze_collection(SUMMARY_BACKUP_KEYS):
             build_multi_tower_prediction_graph(