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mnist_tpu.py
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mnist_tpu.py
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# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""MNIST model training using TPUs.
This program demonstrates training of the convolutional neural network model
defined in mnist.py on Google Cloud TPUs (https://cloud.google.com/tpu/).
If you are not interested in TPUs, you should ignore this file.
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import os
import sys
import tensorflow as tf # pylint: disable=g-bad-import-order
# For open source environment, add grandparent directory for import
sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(sys.path[0]))))
from official.mnist import dataset # pylint: disable=wrong-import-position
from official.mnist import mnist # pylint: disable=wrong-import-position
# Cloud TPU Cluster Resolver flags
tf.flags.DEFINE_string(
"tpu", default=None,
help="The Cloud TPU to use for training. This should be either the name "
"used when creating the Cloud TPU, or a grpc://ip.address.of.tpu:8470 "
"url.")
tf.flags.DEFINE_string(
"tpu_zone", default=None,
help="[Optional] GCE zone where the Cloud TPU is located in. If not "
"specified, we will attempt to automatically detect the GCE project from "
"metadata.")
tf.flags.DEFINE_string(
"gcp_project", default=None,
help="[Optional] Project name for the Cloud TPU-enabled project. If not "
"specified, we will attempt to automatically detect the GCE project from "
"metadata.")
# Model specific parameters
tf.flags.DEFINE_string("data_dir", "",
"Path to directory containing the MNIST dataset")
tf.flags.DEFINE_string("model_dir", None, "Estimator model_dir")
tf.flags.DEFINE_integer("batch_size", 1024,
"Mini-batch size for the training. Note that this "
"is the global batch size and not the per-shard batch.")
tf.flags.DEFINE_integer("train_steps", 1000, "Total number of training steps.")
tf.flags.DEFINE_integer("eval_steps", 0,
"Total number of evaluation steps. If `0`, evaluation "
"after training is skipped.")
tf.flags.DEFINE_float("learning_rate", 0.05, "Learning rate.")
tf.flags.DEFINE_bool("use_tpu", True, "Use TPUs rather than plain CPUs")
tf.flags.DEFINE_integer("iterations", 50,
"Number of iterations per TPU training loop.")
tf.flags.DEFINE_integer("num_shards", 8, "Number of shards (TPU chips).")
FLAGS = tf.flags.FLAGS
def metric_fn(labels, logits):
accuracy = tf.metrics.accuracy(
labels=labels, predictions=tf.argmax(logits, axis=1))
return {"accuracy": accuracy}
def model_fn(features, labels, mode, params):
"""model_fn constructs the ML model used to predict handwritten digits."""
del params
if mode == tf.estimator.ModeKeys.PREDICT:
raise RuntimeError("mode {} is not supported yet".format(mode))
image = features
if isinstance(image, dict):
image = features["image"]
model = mnist.create_model("channels_last")
logits = model(image, training=(mode == tf.estimator.ModeKeys.TRAIN))
loss = tf.losses.sparse_softmax_cross_entropy(labels=labels, logits=logits)
if mode == tf.estimator.ModeKeys.TRAIN:
learning_rate = tf.train.exponential_decay(
FLAGS.learning_rate,
tf.train.get_global_step(),
decay_steps=100000,
decay_rate=0.96)
optimizer = tf.train.GradientDescentOptimizer(learning_rate=learning_rate)
if FLAGS.use_tpu:
optimizer = tf.contrib.tpu.CrossShardOptimizer(optimizer)
return tf.contrib.tpu.TPUEstimatorSpec(
mode=mode,
loss=loss,
train_op=optimizer.minimize(loss, tf.train.get_global_step()))
if mode == tf.estimator.ModeKeys.EVAL:
return tf.contrib.tpu.TPUEstimatorSpec(
mode=mode, loss=loss, eval_metrics=(metric_fn, [labels, logits]))
def train_input_fn(params):
"""train_input_fn defines the input pipeline used for training."""
batch_size = params["batch_size"]
data_dir = params["data_dir"]
# Retrieves the batch size for the current shard. The # of shards is
# computed according to the input pipeline deployment. See
# `tf.contrib.tpu.RunConfig` for details.
ds = dataset.train(data_dir).cache().repeat().shuffle(
buffer_size=50000).apply(
tf.contrib.data.batch_and_drop_remainder(batch_size))
images, labels = ds.make_one_shot_iterator().get_next()
return images, labels
def eval_input_fn(params):
batch_size = params["batch_size"]
data_dir = params["data_dir"]
ds = dataset.test(data_dir).apply(
tf.contrib.data.batch_and_drop_remainder(batch_size))
images, labels = ds.make_one_shot_iterator().get_next()
return images, labels
def main(argv):
del argv # Unused.
tf.logging.set_verbosity(tf.logging.INFO)
tpu_cluster_resolver = tf.contrib.cluster_resolver.TPUClusterResolver(
FLAGS.tpu,
zone=FLAGS.tpu_zone,
project=FLAGS.gcp_project
)
run_config = tf.contrib.tpu.RunConfig(
cluster=tpu_cluster_resolver,
model_dir=FLAGS.model_dir,
session_config=tf.ConfigProto(
allow_soft_placement=True, log_device_placement=True),
tpu_config=tf.contrib.tpu.TPUConfig(FLAGS.iterations, FLAGS.num_shards),
)
estimator = tf.contrib.tpu.TPUEstimator(
model_fn=model_fn,
use_tpu=FLAGS.use_tpu,
train_batch_size=FLAGS.batch_size,
eval_batch_size=FLAGS.batch_size,
params={"data_dir": FLAGS.data_dir},
config=run_config)
# TPUEstimator.train *requires* a max_steps argument.
estimator.train(input_fn=train_input_fn, max_steps=FLAGS.train_steps)
# TPUEstimator.evaluate *requires* a steps argument.
# Note that the number of examples used during evaluation is
# --eval_steps * --batch_size.
# So if you change --batch_size then change --eval_steps too.
if FLAGS.eval_steps:
estimator.evaluate(input_fn=eval_input_fn, steps=FLAGS.eval_steps)
if __name__ == "__main__":
tf.app.run()