Tensorflow Dataset API initialiser hook fix

mnist_new_dataset_hook.py

from __future__ import division, print_function, absolute_import, \
    unicode_literals

import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data as mnist_data
from tensorflow.contrib import slim
from tensorflow.contrib.learn import ModeKeys
from tensorflow.contrib.learn.python.learn import learn_runner


tf.logging.set_verbosity(tf.logging.DEBUG)


# Define data loaders #####################################
MNIST_DATA_FOLDER = './MNIST_data'
mnist = mnist_data.read_data_sets(MNIST_DATA_FOLDER, one_hot=False)


class IteratorInitializerHook(tf.train.SessionRunHook):
    def __init__(self):
        super(IteratorInitializerHook, self).__init__()
        self.iterator_initiliser_func = None

    def after_create_session(self, session, coord):
        self.iterator_initiliser_func(session)


# Define the training inputs
def get_train_inputs(batch_size):
    iterator_initiliser_hook = IteratorInitializerHook()
    def train_inputs():
        with tf.name_scope('Training_data'):
            images = mnist.train.images.reshape([-1, 28, 28, 1])
            labels = mnist.train.labels
            images_placeholder = tf.placeholder(
                images.dtype, images.shape)
            labels_placeholder = tf.placeholder(
                labels.dtype, labels.shape)
            dataset = tf.contrib.data.Dataset.from_tensor_slices(
                (images_placeholder, labels_placeholder))
            dataset = dataset.repeat(None)  # Infinite
            dataset = dataset.shuffle(buffer_size=10000)
            dataset = dataset.batch(batch_size)
            iterator = dataset.make_initializable_iterator()
            next_example, next_label = iterator.get_next()
            # Set runhook to initilise iterator
            iterator_initiliser_hook.iterator_initiliser_func = \
                lambda sess: sess.run(
                    iterator.initializer,
                    feed_dict={images_placeholder: images,
                               labels_placeholder: labels})
            return next_example, next_label
    return train_inputs, iterator_initiliser_hook



def get_test_inputs(batch_size):
    iterator_initiliser_hook = IteratorInitializerHook()
    def test_inputs():
        with tf.name_scope('Test_data'):
            images = mnist.test.images.reshape([-1, 28, 28, 1])
            labels = mnist.test.labels
            images_placeholder = tf.placeholder(
                images.dtype, images.shape)
            labels_placeholder = tf.placeholder(
                labels.dtype, labels.shape)
            dataset = tf.contrib.data.Dataset.from_tensor_slices(
                (images_placeholder, labels_placeholder))
            dataset = dataset.batch(batch_size)
            iterator = dataset.make_initializable_iterator()
            next_example, next_label = iterator.get_next()
            # Set runhook to initilise iterator
            iterator_initiliser_hook.iterator_initiliser_func = \
                lambda sess: sess.run(
                    iterator.initializer,
                    feed_dict={images_placeholder: images,
                               labels_placeholder: labels})
            return next_example, next_label
    return test_inputs, iterator_initiliser_hook


# Define model ############################################
def get_estimator(run_config, hparams):
    return tf.contrib.learn.Estimator(
        model_fn=get_model_fn,
        params=hparams,
        config=run_config
    )


def get_model_fn(inputs, targets, mode, params):
    # Define model's architecture
    logits = architecture(inputs, is_training=mode == ModeKeys.TRAIN)
    head = tf.contrib.learn.multi_class_head(
        n_classes=params.n_classes,
        loss_fn=tf.losses.sparse_softmax_cross_entropy)
    return head.create_model_fn_ops(
        features={'inputs': inputs},
        labels=tf.cast(targets, tf.int32),
        mode=mode,
        train_op_fn=get_train_op_fn(params),
        logits=logits
    )


def get_train_op_fn(params):
    def train_op_fn(loss):
        return tf.contrib.layers.optimize_loss(
            loss=loss,
            global_step=tf.contrib.framework.get_global_step(),
            optimizer=tf.train.AdamOptimizer,
            learning_rate=params.learning_rate
        )
    return train_op_fn


def architecture(inputs, is_training, scope='MnistConvNet'):
    tf.logging.debug('is_training: {}, {}'.format(type(is_training), is_training))
    with tf.variable_scope(scope):
        with slim.arg_scope(
                [slim.conv2d, slim.fully_connected],
                weights_initializer=tf.contrib.layers.xavier_initializer()):
            net = slim.conv2d(inputs, 20, [5, 5], padding='VALID',
                              scope='layer1-conv')
            net = slim.max_pool2d(net, 2, stride=2, scope='layer2-max-pool')
            net = slim.conv2d(net, 40, [5, 5], padding='VALID',
                              scope='layer3-conv')
            net = slim.max_pool2d(net, 2, stride=2, scope='layer4-max-pool')
            net = tf.reshape(net, [-1, 4 * 4 * 40])
            net = slim.fully_connected(net, 256, scope='layer5')
            net = slim.dropout(net, is_training=is_training,
                               scope='layer5-dropout')
            net = slim.fully_connected(net, 256, scope='layer6')
            net = slim.dropout(net, is_training=is_training,
                               scope='layer6-dropout')
            net = slim.fully_connected(net, 10, scope='output',
                                       activation_fn=None)
        return net


def create_experiment(run_config, hparams):
    # You can change a subset of the run_config properties as
    run_config = run_config.replace(save_checkpoints_steps=500)
    # Define the mnist classifier
    estimator = get_estimator(run_config, hparams)
    # Setup data loaders
    train_input_fn, train_input_hook = get_train_inputs(batch_size=128)
    eval_input_fn, eval_input_hook = get_test_inputs(batch_size=128)
    # Define the experiment
    experiment = tf.contrib.learn.Experiment(
        estimator=estimator,
        train_input_fn=train_input_fn,
        eval_input_fn=eval_input_fn,
        train_steps=5000,
        min_eval_frequency=500,
        train_monitors=[train_input_hook],
        eval_hooks=[eval_input_hook],
        eval_steps=None  # Use evaluation feeder until its empty
    )
    return experiment



def main(unused_argv=None):
    model_dir = './mnist_training_new_dataset_hook'

    # Define model parameters
    hparams = tf.contrib.training.HParams(
        learning_rate=0.002,
        n_classes=10
    )

    learn_runner.run(
        experiment_fn=create_experiment,
        run_config=tf.contrib.learn.RunConfig(model_dir=model_dir),
        schedule="train_and_evaluate",
        hparams=hparams)


if __name__ == "__main__":
    tf.app.run()

@yzhangswingman I hit this exact problem. Did you manage to solve it?

@wohlbier oh hey, I actually cannot recall at all. Sorry about that. Don’t know if this is helpful but I switched to tf.keras api altogether since TF2 since it seems to be more stable and better maintained.