Argparse error with TensorFlow's cifar10.py - argparse

Question

I get the following error when I run python cifar10.py:
argparse.ArgumentError: argument --batch_size: conflicting option string(s): --batch_size
Here's the full output of the run including a complete trace:
I tensorflow/stream_executor/dso_loader.cc:101] successfully opened CUDA library libcublas.so.7.0 locally
I tensorflow/stream_executor/dso_loader.cc:101] successfully opened CUDA library libcudnn.so.6.5 locally
I tensorflow/stream_executor/dso_loader.cc:101] successfully opened CUDA library libcufft.so.7.0 locally
I tensorflow/stream_executor/dso_loader.cc:101] successfully opened CUDA library libcuda.so locally
I tensorflow/stream_executor/dso_loader.cc:101] successfully opened CUDA library libcurand.so.7.0 locally
Traceback (most recent call last):
File "cifar10.py", line 54, in <module>
"""Number of images to process in a batch.""")
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/platform/default/_flags.py", line 86, in DEFINE_integer
_define_helper(flag_name, default_value, docstring, int)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/platform/default/_flags.py", line 60, in _define_helper
type=flagtype)
File "/usr/lib/python2.7/argparse.py", line 1297, in add_argument
return self._add_action(action)
File "/usr/lib/python2.7/argparse.py", line 1671, in _add_action
self._optionals._add_action(action)
File "/usr/lib/python2.7/argparse.py", line 1498, in _add_action
action = super(_ArgumentGroup, self)._add_action(action)
File "/usr/lib/python2.7/argparse.py", line 1311, in _add_action
self._check_conflict(action)
File "/usr/lib/python2.7/argparse.py", line 1449, in _check_conflict
conflict_handler(action, confl_optionals)
File "/usr/lib/python2.7/argparse.py", line 1456, in _handle_conflict_error
raise ArgumentError(action, message % conflict_string)
argparse.ArgumentError: argument --batch_size: conflicting option string(s): --batch_size
This error seems to come from the following line in cifar10.py: tf.app.flags.DEFINE_integer('batch_size', 128, """Number of images to process in a batch.""")
It seems like the argparse library thinks that I've already defined the option string --batch_size, but I haven't.
[Stack: Amazon g2.2xlarge spot instance, Python 2.7.6]

Answer 1

In the cifr10.py file:
import tensorflow as tf
from tensorflow.models.image.cifar10 import cifar10_input
FLAGS = tf.app.flags.FLAGS
# Basic model parameters.
tf.app.flags.DEFINE_integer('batch_size', 128,
"""Number of images to process in a batch.""")
....
The error is produced by this last statement, which, in the _flags.py file, defines an argparse argument with that name. Evidently at this point the tf.app already has such an argument define.
So we need to look further back at import tensorflow as tf to see how tf.app was created?
What's the Amazon g2.2xlarge? Could that defining batch_size as well?
Looks like tf.app comes from
tensorflow/python/platform/app.py
which in turn gets it from something like
from tensorflow.python.platform.google._app import *
So if you are running this on some google or amazon platform that itself accepts batch_size parameter, it could produce this error.
Another question about cifr10 and the batch_size argument:
How to use "FLAGS" (command line switches) in TensorFlow?
Same error here:
Tensorflow ArgumentError Running CIFAR-10 example
The answer says to use cifar10_train.py,cifar10_eval.py, not cifar10.py.