Revert "create_scalar_summary -> tb.summary.scalar_pb"

This reverts commit 77cee2b2.

tensorpack/callbacks/monitor.py

@@ -14,9 +14,8 @@ import json
 import re
 
 import tensorflow as tf
-import tensorboard as tb
 from ..utils import logger
-from ..tfutils.summary import create_image_summary
+from ..tfutils.summary import create_scalar_summary, create_image_summary
 from .base import Callback
 
 __all__ = ['TrainingMonitor', 'Monitors',
@@ -162,7 +161,7 @@ class Monitors(Callback):
         if isinstance(val, np.integer):
             val = int(val)
         self._dispatch(lambda m: m.process_scalar(name, val))
-        s = tb.summary.scalar_pb(name, val)
+        s = create_scalar_summary(name, val)
         self._dispatch(lambda m: m.process_summary(s))
 
     def put_image(self, name, val):

tensorpack/tfutils/summary.py

@@ -39,6 +39,21 @@ def _enter_vs_reuse_ns(name):
             yield vs
 
 
+def create_scalar_summary(name, v):
+    """
+    Args:
+        name (str):
+        v (float): scalar value
+    Returns:
+        tf.Summary: a tf.Summary object with name and simple scalar value v.
+    """
+    assert isinstance(name, six.string_types), type(name)
+    v = float(v)
+    s = tf.Summary()
+    s.value.add(tag=name, simple_value=v)
+    return s
+
+
 def create_image_summary(name, val):
     """
     Args: