fix bug in last commit.

tensorpack/callbacks/monitor.py

@@ -306,7 +306,7 @@ class JSONWriter(TrainingMonitor):
         except Exception:
             return None
 
-    def _before_train(self):
+    def _setup_graph(self):
         stats = JSONWriter.load_existing_json()
         self._fname = os.path.join(logger.get_logger_dir(), JSONWriter.FILENAME)
         if stats is not None:
@@ -340,6 +340,10 @@ class JSONWriter(TrainingMonitor):
 
         self._last_gs = -1
 
+    # in case we have something to log here.
+    def _before_train(self):
+        self._trigger()
+
     def _trigger_step(self):
         # will do this in trigger_epoch
         if self.local_step != self.trainer.steps_per_epoch - 1:
@@ -407,6 +411,10 @@ class ScalarPrinter(TrainingMonitor):
         self._enable_epoch = enable_epoch
         self._dic = {}
 
+    # in case we have something to log here.
+    def _before_train(self):
+        self._trigger()
+
     def _trigger_step(self):
         if self._enable_step:
             if self.local_step != self.trainer.steps_per_epoch - 1:

tensorpack/callbacks/trigger.py

@@ -38,11 +38,11 @@ class PeriodicTrigger(ProxyCallback):
                 "Arguments to PeriodicTrigger have disabled the triggerable!"
         self._step_k = every_k_steps
         self._epoch_k = every_k_epochs
-        self._before_train = before_train
+        self._do_before_train = before_train
 
     def _before_train(self):
         self.cb.before_train()
-        if self._before_train:
+        if self._do_before_train:
             self.cb.trigger()
 
     def _trigger_step(self):