CODEWITHSUNDEEP
pythonpython-3.xtensorflow
pepe
pepe

Reputation: 9909

Tensorflow session returns as 'closed'

I have successfully ported the CIFAR-10 ConvNet tutorial code for my own images and am able to train on my data and generate Tensorboard outputs etc.

My next step was to implement an evaluation of new data against the model I built. I am trying now to use cifar10_eval.py as a starting point however am running into some difficulty.

I should point out that the original tutorial code runs entirely without a problem, including cifar10_eval.py. However, when moving this particular code to my application, I get the following error message (last line).

RuntimeError: Attempted to use a closed Session.

I found this error is thrown by TF's session.py

# Check session.
if self._closed:
  raise RuntimeError('Attempted to use a closed Session.')

I have checked the directories in which all files should reside and be created, and all seems exactly as it should (they mirror perfectly those created by running the original tutorial code). They include a train, eval and data folders, containing checkpoints/events files, events file, and data binaries respectively.

I wonder if you could help pointing out how I can debug this, as I'm sure there may be something in the data flow that got disrupted when transitioning the code. Unfortunately, despite digging deep and comparing to the original, I can't find the source, as they are essentially similar with trivial changes in file names and destination directories only.

EDIT_01: Debugging step by step, it seems the line that actually throws the error is #106 in the original cifar10_eval.py:

    def eval_once(args etc)
    ...    
      with tf.Session() as sess:
      ...   
        summary = tf.Summary()
        summary.ParseFromString(sess.run(summary_op))  # <========== line 106

summary_op is created in def evaluate of this same script and passed as an arg to def eval_once.

summary_op = tf.merge_all_summaries()
...
while True:
  eval_once(saver, summary_writer, top_k_op, summary_op)

Upvotes: 1

Views: 3426

Answers (2)

pepe
pepe

Reputation: 9909

It was a simple (but humbling) error in indentation.

        summary = tf.Summary()
        summary.ParseFromString(sess.run(summary_op))
        summary.value.add(tag='Precision @ 1', simple_value=precision)
        summary_writer.add_summary(summary, global_step)

was outside of the try: block, and of course, no session could be found.

Sigh.

Upvotes: 1

Yaroslav Bulatov
Yaroslav Bulatov

Reputation: 57893

From documentation on Session, a session can be closed with .close command or when using it through a context-manager in with block. I did find tensorflow/models/image/cifar10 | xargs grep "sess" and I don't see any sess.close, so it must be the later.

IE, you'll get this error if you do something like this

with tf.Session() as sess:
   sess.run(..)

sess.run(...)  # Attempted to use a closed Session.

Upvotes: 2

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