fix MergeAllSummaries 'run_alone' option (fix #206)

examples/mnist-convnet.py

@@ -78,6 +78,7 @@ class Model(ModelDesc):
                           .FullyConnected('fc0', 512, nl=tf.nn.relu)
                           .Dropout('dropout', 0.5)
                           .FullyConnected('fc1', out_dim=10, nl=tf.identity)())
+
         prob = tf.nn.softmax(logits, name='prob')   # a Bx10 with probabilities
 
         # a vector of length B with loss of each sample

tensorpack/callbacks/summary.py

@@ -73,3 +73,7 @@ class MergeAllSummaries(Callback):
     def _trigger(self):
         summary = self.summary_op.eval()
         self.trainer.monitors.put_summary(summary)
+
+    def _trigger_epoch(self):
+        if self._run_alone:
+            self._trigger()