bug fix

examples/OpenAIGym/train-atari.py

@@ -246,14 +246,16 @@ if __name__ == '__main__':
             train_tower = range(nr_gpu)[:-nr_gpu//2] or [0]
             logger.info("[BA3C] Train on gpu {} and infer on gpu {}".format(
                 ','.join(map(str, train_tower)), ','.join(map(str, predict_tower))))
+            trainer = AsyncMultiGPUTrainer
         else:
             logger.warn("Without GPU this model will never learn! CPU is only useful for debug.")
             nr_gpu = 0
             PREDICTOR_THREAD = 1
             predict_tower = [0]
             train_tower = [0]
+            trainer = QueueInputTrainer
         config = get_config()
         if args.load:
             config.session_init = SaverRestore(args.load)
         config.tower = train_tower
-        AsyncMultiGPUTrainer(config, predict_tower=predict_tower).train()
+        trainer(config, predict_tower=predict_tower).train()

tensorpack/train/base.py

@@ -93,7 +93,7 @@ class Trainer(object):
                 val.tag = re.sub('tower[p0-9]+/', '', val.tag)   # TODO move to subclasses
                 suffix = '-summary' # issue#6150
                 if val.tag.endswith(suffix):
-                    val.tag = va.tag[:-len(suffix)]
+                    val.tag = val.tag[:-len(suffix)]
                 self.stat_holder.add_stat(val.tag, val.simple_value)
         self.summary_writer.add_summary(summary, get_global_step())
 

tensorpack/train/multigpu.py

@@ -56,6 +56,7 @@ class SyncMultiGPUTrainer(MultiGPUTrainer,
 
         self._setup_predictor_factory(predict_tower)
         assert len(config.tower) >= 1, "MultiGPUTrainer must be used with at least one GPU."
+        assert tf.test.is_gpu_available()
 
 
     @staticmethod
@@ -110,6 +111,7 @@ class AsyncMultiGPUTrainer(MultiGPUTrainer,
 
         self._setup_predictor_factory(predict_tower)
         self._average_gradient = average_gradient
+        assert tf.test.is_gpu_available()
 
     def _setup(self):
         super(AsyncMultiGPUTrainer, self)._setup()