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"""Pipeline for training a model that can read time from clock images.
This sets up a model and loss function, runs the optimization, and prints
performance statistics on a regular basis. It also saves the model and summaries
to disk (so they can be visualized in Tensorboard).
This pipeline is strongly inspired by the cifar10 pipeline.
- The data is loaded from
- The model is built in
- For evaluating the trained model, see
import tensorflow as tf
import numpy as np
from datetime import datetime
import time
import os.path
import clock_model
import clock_data
FLAGS ='train_dir', './tf_data',
"""Directory where to write event logs """
"""and checkpoint.""")'max_steps', 800,
"""Number of batches to run.""")'log_device_placement', False,
"""Whether to log device placement.""")
def train(summary_path):
""" Builds and trains the clock reading model. """
with tf.Graph().as_default():
global_step = tf.Variable(0, trainable=False)
images, (labels_hours, labels_minutes), num_records, num_classes = \
batch_size=FLAGS.batch_size, filename='clocks_train.txt')
tf.image_summary("images/input", images) # Visualize some input clocks.
print('Training on {} images.'.format(num_records))
print('Saving output to {}'.format(summary_path))
# Build a Graph that computes the logits predictions from the
# inference model in a multi-task learning .
(logits_hours, logits_minutes) = clock_model.inference_multitask(images)
logits = (logits_hours, logits_minutes)
# Calculate loss.
loss = clock_model.loss_multitask(logits_hours, labels_hours,
logits_minutes, labels_minutes)
# Compute accuracy (how often prediction is correct) for both minutes
# and hours separately. in_top_k returns how often the true label is in
# the top k of the predictions, k = 1 means only a match gets counted.
train_accuracy_h_op = tf.nn.in_top_k(logits_hours, labels_hours, 1)
train_accuracy_m_op = tf.nn.in_top_k(logits_minutes, labels_minutes, 1)
# This operation computes the actual time error in minutes (i.e. how far
# off our prediction was).
time_error_losses = clock_model.time_error_loss(
logits_hours, logits_minutes, labels_hours, labels_minutes)
# Build a Graph that trains the model with one batch of examples and
# updates the model parameters.
train_op = clock_model.train(loss, global_step)
# Create a saver.
saver = tf.train.Saver(tf.all_variables())
# Build the summary operation based on the TF collection of Summaries.
summary_op = tf.merge_all_summaries()
# Build an initialization operation to run below.
init = tf.initialize_all_variables()
# Start running operations on the Graph.
sess = tf.Session(config=tf.ConfigProto(
# Start the queue runners.
coord = tf.train.Coordinator()
threads = tf.train.start_queue_runners(sess=sess, coord=coord)
summary_writer = tf.train.SummaryWriter(summary_path, sess.graph)
for step in range(FLAGS.max_steps):
start_time = time.time()
_, loss_value =[train_op, loss])
duration = time.time() - start_time
assert not np.isnan(loss_value), 'Model diverged with loss = NaN'
# Loss and timing statistics.
if step % 20 == 0:
num_examples_per_step = FLAGS.batch_size
examples_per_sec = num_examples_per_step / duration
sec_per_batch = float(duration)
format_str = ('%s: step %d, loss = %.2f (%.1f examples/sec; '
'%.3f sec/batch)')
print (format_str % (, step, loss_value,
examples_per_sec, sec_per_batch))
# Compute **training** set precision and time error.
if step % 30 == 0:
# Evaluate the precision of all the top-k operators.
precisions, total_count = clock_model.evaluate_precision(
sess, coord, num_records, FLAGS.batch_size,
[train_accuracy_h_op, train_accuracy_m_op])
precision_h, precision_m = precisions
print('%s: training set precision = %.3f(h) %.3f(m) \t '
'(%d samples)' % (, precision_h,
precision_m, total_count))
# Add it to summary writer.
precision_summary_h = tf.scalar_summary(
'training_precision/hours', precision_h)
precision_summary_m = tf.scalar_summary(
'training_precision/minutes', precision_m)
precision_summary_c = tf.scalar_summary(
(precision_h + precision_m) * 0.5)
# Compute time error in minutes.
(time_err_c, time_err_h, time_err_m) =
print('%s: training set time error = %.3fm (total) \t'
' %.3f(h) %.3f(m)'
% (, time_err_c, time_err_h, time_err_m))
time_summary_c = tf.scalar_summary(
'training_error/combined', time_err_c)
time_summary_h = tf.scalar_summary(
'training_error/hours_only', time_err_h)
time_summary_m = tf.scalar_summary(
'training_error/minutes_only', time_err_m)
summaries =[precision_summary_c, precision_summary_h,
precision_summary_m, time_summary_c,
time_summary_h, time_summary_m])
for summary in summaries:
summary_writer.add_summary(summary, global_step=step)
# Run summary writers for tensorboard
if step % 20 == 0:
summary_str =
summary_writer.add_summary(summary_str, step)
# Save the model checkpoint periodically.
if step % 25 == 0 or (step + 1) == FLAGS.max_steps:
checkpoint_path = os.path.join(summary_path, 'model.ckpt'), checkpoint_path, global_step=step)
print('%s: saved model at step %d' % (, step))
# When done, ask the threads to stop.
def main(argv=None): # pylint: disable=unused-argument
time_str = time.strftime('%H.%M.%S')
summary_path = os.path.join(FLAGS.train_dir, 'run_{}'.format(time_str))
if __name__ == '__main__':