infinite option in FeedInput

tensorpack/callbacks/inference_runner.py

@@ -115,8 +115,14 @@ class InferenceRunnerBase(Callback):
 
         # iterate over the data, and run the hooked session
         self._input_source.reset_state()
-        for _ in tqdm.trange(self._size, **get_tqdm_kwargs()):
-            self._hooked_sess.run(fetches=[])
+        msg = "You might need to check your input implementation."
+        try:
+            for _ in tqdm.trange(self._size, **get_tqdm_kwargs()):
+                self._hooked_sess.run(fetches=[])
+        except StopIteration:
+            raise RuntimeError(
+                "[InferenceRunner] input stopped before reaching its size()! " + msg)
+
         summary_inferencer(self.trainer, self.infs)
 
 
@@ -133,7 +139,7 @@ class InferenceRunner(InferenceRunnerBase):
             infs (list): a list of :class:`Inferencer` instances.
         """
         if isinstance(input, DataFlow):
-            input = FeedInput(input)
+            input = FeedInput(input, infinite=False)
         assert isinstance(input, InputSource), input
         if isinstance(input, FeedfreeInput):    # TODO support other input
             assert isinstance(input, TensorInput), "InferenceRunner only accepts TensorInput or FeedInput!"

tensorpack/graph_builder/input_source.py

@@ -65,22 +65,26 @@ class FeedInput(InputSource):
             self._ds.reset_state()
             self._itr = self._ds.get_data()
 
-    def __init__(self, ds):
+    def __init__(self, ds, infinite=True):
         """
         Args:
             ds (DataFlow): the input DataFlow.
+            infinite (bool): When set to False, will raise StopIteration when
+                ds is exhausted.
         """
         assert isinstance(ds, DataFlow), ds
         self.ds = ds
-        # TODO avoid infinite repeat, to allow accurate size handling
-        self._repeat_ds = RepeatedData(self.ds, -1)
+        if infinite:
+            self._iter_ds = RepeatedData(self.ds, -1)
+        else:
+            self._iter_ds = self.ds
 
     def _size(self):
         return self.ds.size()
 
     def _setup(self, inputs):
         self._all_placehdrs = [v.build_placeholder(prefix='') for v in inputs]
-        self._cb = self._FeedCallback(self._repeat_ds, self._all_placehdrs)
+        self._cb = self._FeedCallback(self._iter_ds, self._all_placehdrs)
         self.reset_state()
 
     def _get_input_tensors(self):