compatibility bug fix

CHANGES.md

@@ -8,7 +8,7 @@ so you won't need to look at here very often.
 Here are a list of things that were changed, starting from an early version.
 TensorFlow itself also changes API and those are not listed here.
 
-* 2017/01/27. `TrainConfig(step_per_epoch)` was renamed to `steps_per_epoch`.
+* 2017/01/27. `TrainConfig(step_per_epoch)` was renamed to `steps_per_epoch`. See [commit](https://github.com/ppwwyyxx/tensorpack/commit/a9dd0b8ec34209ab86a92875589dbbc4716e73ef).
 * 2017/01/25. Argument order of `models.ConcatWith` is changed to follow the API change in
 	TensorFlow upstream. See [commit](https://github.com/ppwwyyxx/tensorpack/commit/2df3dcf401a99fe61c699ad719e95528872d3abe).
 * 2017/01/25. `TrainConfig(callbacks=)` now takes a list of `Callback` instances. See [commit](https://github.com/ppwwyyxx/tensorpack/commit/243e957fe6d62a0cfb5728bd77fb3e005d6603e4)

tensorpack/callbacks/group.py

@@ -60,20 +60,20 @@ class Callbacks(Callback):
             assert isinstance(cb, Callback), cb.__class__
         # move "StatPrinter" to the last
         # TODO don't need to manually move in the future.
-        found = False
         for idx, cb in enumerate(cbs):
             if isinstance(cb, StatPrinter):
-                if found:
-                    raise ValueError("Callbacks cannot contain two StatPrinter!")
                 sp = cb
                 cbs.remove(sp)
                 cbs.append(sp)
                 if idx != len(cbs) - 1:
                     logger.warn("StatPrinter should appear as the last element of callbacks! "
                                 "This is now fixed automatically, but may not work in the future.")
-                found = True
-        if not found:
+                break
+        else:
             raise ValueError("Callbacks must contain StatPrinter for stat and writer to work properly!")
+        nr_printer = sum([int(isinstance(cb, StatPrinter)) for cb in cbs])
+        if nr_printer != 1:
+            raise ValueError("Callbacks must contain one StatPrinter!")
 
         self.cbs = cbs
         self._extra_fetches_cache = None

tensorpack/callbacks/stats.py

@@ -9,7 +9,6 @@ import json
 from .base import Callback
 from .trigger import Triggerable
 from ..utils import logger
-from ..tfutils.common import get_global_step_value
 
 __all__ = ['StatHolder', 'StatPrinter', 'SendStat']
 
@@ -135,8 +134,9 @@ class StatPrinter(Callback):
 
     def _trigger_epoch(self):
         # by default, add this two stat
-        self._stat_holder.add_stat('global_step', get_global_step_value())
+        self._stat_holder.add_stat('global_step', self.global_step)
         self._stat_holder.finalize()
+        # this is for the next group of stat
         self._stat_holder.add_stat('epoch_num', self.epoch_num + 1)