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01:17
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SDA.predict()   A

Complexity

Conditions 3

Size

Total Lines 8

Duplication

Lines 0
Ratio 0 %

Importance

Changes 1
Bugs 0 Features 0
Metric Value
cc 3
c 1
b 0
f 0
dl 0
loc 8
rs 9.4285
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import logging
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import numpy as np
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import tensorflow as tf
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from .layers import AutoencoderLayer, HiddenLayer, SoftmaxLayer
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from .injectors import BatchInjector
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from .criterion import MonitorBased, ConstIterations
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logger = logging.getLogger(__name__)
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class SDA:
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    """Stacked Auto-encoder
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    Args:
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        num_features (:obj:`int`): Number of features.
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        num_classes (:obj:`int`): Number of classes.
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        layers (:obj:`list` of :obj:`int`): Series of hidden auto-encoder layers.
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        encode_optimizer: Optimizer used for auto-encoding process.
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        tuning_optimizer: Optimizer used for fine tuning.
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    Attributes:
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        num_features (:obj:`int`): Number of features.
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        num_classes (:obj:`int`): Number of classes.
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        x (:obj:`tensorflow.placeholder`): Input placeholder.
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        y_ (:obj:`tensorflow.placeholder`): Output placeholder.
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        inner_layers (:obj:`list`): List of auto-encoder hidden layers.
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    """
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    def __init__(self, num_features, num_classes, layers, encode_optimizer=None, tuning_optimizer=None):
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        self.num_features = num_features
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        self.num_classes = num_classes
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        with tf.name_scope('input'):
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            self.x = tf.placeholder(tf.float32, shape=[None, num_features], name='input_x')
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            self.y_ = tf.placeholder(tf.float32, shape=[None, num_classes], name='input_y')
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        self.inner_layers = []
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        self.summaries = []
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        self.encode_opts = []
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        if encode_optimizer is None:
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            self.encode_optimizer = tf.train.AdamOptimizer()
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        else:
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            self.encode_optimizer = encode_optimizer
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        if tuning_optimizer is None:
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            self.tuning_optimizer = tf.train.AdamOptimizer()
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        else:
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            self.tuning_optimizer = tuning_optimizer
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        # Create Layers
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        for i in range(len(layers)):
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            if i == 0:
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                # First Layer
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                self.inner_layers.append(
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                    AutoencoderLayer(num_features, layers[i], x=self.x, name=('Hidden%d' % i))
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                )
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            else:
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                # inner Layer
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                self.inner_layers.append(
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                    AutoencoderLayer(layers[i-1], layers[i], x=self.inner_layers[i-1].y, name=('Hidden%d' % i))
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                )
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            self.summaries += self.inner_layers[i].summaries
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            self.encode_opts.append(
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                self.encode_optimizer.minimize(self.inner_layers[i].encode_loss,
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                                               var_list=self.inner_layers[i].variables)
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            )
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        if num_classes == 1:
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            # Output Layers
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            self.output_layer = HiddenLayer(layers[len(layers) - 1], num_classes, x=self.inner_layers[len(layers)-1].y,
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                                            name='Output', activation_fn=tf.sigmoid)
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            # Predicted Probability
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            self.y = self.output_layer.y
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            self.y_class = tf.cast(tf.greater_equal(self.y, 0.5), tf.float32)
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            # Loss
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            self.loss = tf.reduce_mean(
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                tf.nn.sigmoid_cross_entropy_with_logits(self.output_layer.logits, self.y_,
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                                                        name='SigmoidCrossEntropyLoss')
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            )
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            self.correct_prediction = tf.equal(self.y_class, self.y_)
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            self.accuracy = tf.reduce_mean(tf.cast(self.correct_prediction, tf.float32))
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        else:
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            # Output Layers
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            self.output_layer = SoftmaxLayer(layers[len(layers) - 1], num_classes, x=self.inner_layers[len(layers)-1].y,
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                                             name='OutputLayer')
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            # Predicted Probability
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            self.y = self.output_layer.y
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            self.y_class = tf.argmax(self.y, 1)
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            # Loss
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            self.loss = tf.reduce_mean(
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                tf.nn.softmax_cross_entropy_with_logits(self.output_layer.logits, self.y_,
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                                                        name='SoftmaxCrossEntropyLoss')
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            )
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            self.correct_prediction = tf.equal(self.y_class, tf.argmax(self.y_, 1))
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            self.accuracy = tf.reduce_mean(tf.cast(self.correct_prediction, tf.float32))
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        self.summaries.append(tf.summary.scalar('cross_entropy', self.loss))
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        self.summaries.append(tf.summary.scalar('accuracy', self.accuracy))
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        self.summaries += self.output_layer.summaries
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        with tf.name_scope('train'):
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            self.fine_tuning = self.tuning_optimizer.minimize(self.loss)
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        self.merged = tf.summary.merge(self.summaries)
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        self.sess = None
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    def fit(self, x, y, batch_size=100,
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            pretrain_iter_num=100, pretrain_criterion='const_iterations',
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            tuning_iter_num=100, tuning_criterion='const_iterations',
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            summaries_dir=None, test_x=None, test_y=None, summary_interval=10,
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            session=None):
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        """Fit the model to the dataset
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        Args:
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            x (:obj:`numpy.ndarray`): Input features of shape (num_samples, num_features).
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            y (:obj:`numpy.ndarray`): Corresponding Labels of shape (num_samples) for binary classification,
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                or (num_samples, num_classes) for multi-class classification.
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            batch_size (:obj:`int`): Batch size used in gradient descent.
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            pretrain_iter_num (:obj:`int`): Number of const iterations or search depth for monitor based stopping
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                criterion in pre-training stage
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            pretrain_criterion (:obj:`str`): Stopping criteria in pre-training stage ('const_iterations' or
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                'monitor_based')
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            tuning_iter_num (:obj:`int`): Number of const iterations or search depth for monitor based stopping
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                criterion in fine-tuning stage
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            tuning_criterion (:obj:`str`): Stopping criteria in fine-tuning stage ('const_iterations' or
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                'monitor_based')
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            summaries_dir (:obj:`str`): Path of the directory to store summaries and saved values.
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            summary_interval (:obj:`int`): The step interval to export variable summaries.
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            test_x (:obj:`numpy.ndarray`): Test feature array used for monitoring training progress.
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            test_y (:obj:`numpy.ndarray): Test label array used for monitoring training progress.
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            session (:obj:`tensorflow.Session`): Session to run training functions.
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        """
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        if session is None:
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            if self.sess is None:
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                session = tf.Session()
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                self.sess = session
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            else:
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                session = self.sess
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        session.run(tf.global_variables_initializer())
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        # Pre-training stage: layer by layer
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        for j in range(len(self.inner_layers)):
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            current_layer = self.inner_layers[j]
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            if summaries_dir is not None:
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                layer_summaries_dir = '%s/pretrain_layer%d' % (summaries_dir, j)
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                train_writer = tf.summary.FileWriter(layer_summaries_dir + '/train')
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                test_writer = tf.summary.FileWriter(layer_summaries_dir + '/test')
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                valid_writer = tf.summary.FileWriter(layer_summaries_dir + '/valid')
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            # Get Stopping Criterion
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            if pretrain_criterion == 'const_iterations':
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                _pretrain_criterion = ConstIterations(num_iters=pretrain_iter_num)
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                train_x = x
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                train_y = y
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            elif pretrain_criterion == 'monitor_based':
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                num_samples = x.shape[0]
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                valid_set_len = int(1 / 5 * num_samples)
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                valid_x = x[num_samples - valid_set_len:num_samples, :]
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                valid_y = y[num_samples - valid_set_len:num_samples, :]
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                train_x = x[0:num_samples - valid_set_len, :]
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                train_y = y[0:num_samples - valid_set_len, :]
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                _pretrain_criterion = MonitorBased(n_steps=pretrain_iter_num,
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                                                   monitor_fn=self.get_encode_loss,
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                                                   monitor_fn_args=(current_layer, valid_x, valid_y),
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                                                   save_fn=tf.train.Saver().save,
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                                                   save_fn_args=(session, layer_summaries_dir + '/best.ckpt'))
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            else:
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                logger.error('Wrong criterion %s specified.' % pretrain_criterion)
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                return
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            injector = BatchInjector(data_x=train_x, data_y=train_y, batch_size=batch_size)
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            i = 0
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            while _pretrain_criterion.continue_learning():
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                batch_x, batch_y = injector.next_batch()
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                if summaries_dir is not None and (i % summary_interval == 0):
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                    summary, loss = session.run(
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                        [current_layer.merged, current_layer.encode_loss],
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                        feed_dict={self.x: x, self.y_: y}
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                    )
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                    train_writer.add_summary(summary, i)
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                    logger.info('Pre-training Layer %d, Step %d, training loss %g' % (j, i, loss))
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                    if test_x is not None and test_y is not None:
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                        summary, loss = session.run(
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                            [current_layer.merged, current_layer.encode_loss],
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                            feed_dict={self.x: test_x, self.y_: test_y}
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                        )
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                        test_writer.add_summary(summary, i)
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                        logger.info('Pre-training Layer %d, Step %d, test loss %g' % (j, i, loss))
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                    if pretrain_criterion == 'monitor_based':
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                        summary, loss = session.run(
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                            [current_layer.merged, current_layer.encode_loss],
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                            feed_dict={self.x: valid_x, self.y_: valid_y}
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                        )
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                        valid_writer.add_summary(summary, i)
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                        logger.info('Pre-training Layer %d, Step %d, valid loss %g' % (j, i, loss))
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                loss, _ = session.run(
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                    [current_layer.encode_loss, self.encode_opts[j]],
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                    feed_dict={self.x: batch_x, self.y_: batch_y}
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                )
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                logger.info('Pre-training Layer %d, Step %d, training loss %g' % (j, i, loss))
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                i += 1
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            if pretrain_criterion == 'monitor_based':
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                tf.train.Saver().restore(session, layer_summaries_dir + '/best.ckpt')
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            if summaries_dir is not None:
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                train_writer.close()
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                test_writer.close()
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                valid_writer.close()
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        # Finish all internal layer-by-layer pre-training
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        # Start fine tuning
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        if summaries_dir is not None:
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            tuning_summaries_dir = '%s/fine_tuning' % summaries_dir
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            train_writer = tf.summary.FileWriter(tuning_summaries_dir + '/train')
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            test_writer = tf.summary.FileWriter(tuning_summaries_dir + '/test')
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            valid_writer = tf.summary.FileWriter(tuning_summaries_dir + '/valid')
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        # Setup Stopping Criterion
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        if tuning_criterion == 'const_iterations':
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            _tuning_criterion = ConstIterations(num_iters=pretrain_iter_num)
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            train_x = x
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            train_y = y
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        elif tuning_criterion == 'monitor_based':
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            num_samples = x.shape[0]
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            valid_set_len = int(1 / 5 * num_samples)
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            valid_x = x[num_samples - valid_set_len:num_samples, :]
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            valid_y = y[num_samples - valid_set_len:num_samples, :]
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            train_x = x[0:num_samples - valid_set_len, :]
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            train_y = y[0:num_samples - valid_set_len, :]
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            _tuning_criterion = MonitorBased(n_steps=pretrain_iter_num,
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                                             monitor_fn=self.predict_accuracy,
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                                             monitor_fn_args=(valid_x, valid_y),
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                                             save_fn=tf.train.Saver().save,
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                                             save_fn_args=(session, tuning_summaries_dir + '/best.ckpt'))
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        else:
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            logger.error('Wrong criterion %s specified.' % pretrain_criterion)
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            return
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        injector = BatchInjector(data_x=train_x, data_y=train_y, batch_size=batch_size)
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        i = 0
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        while _tuning_criterion.continue_learning():
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            batch_x, batch_y = injector.next_batch()
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            if summaries_dir is not None and (i % summary_interval == 0):
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                summary, loss, accuracy = session.run([self.merged, self.loss, self.accuracy],
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                                                      feed_dict={self.x: train_x, self.y_: train_y})
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                train_writer.add_summary(summary, i)
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                logger.info('Fine-Tuning: Step %d, training accuracy %g, loss %g' % (i, accuracy, loss))
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                if (test_x is not None) and (test_y is not None):
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                    merged, accuracy = session.run([self.merged, self.accuracy],
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                                                   feed_dict={self.x: test_x, self.y_: test_y})
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                    test_writer.add_summary(merged, i)
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                    logger.info('Fine-Tuning: Step %d, test accuracy %g' % (i, accuracy))
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                if tuning_criterion == 'monitor_based':
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                    merged, accuracy = session.run([self.merged, self.accuracy],
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                                                   feed_dict={self.x: valid_x, self.y_: valid_y})
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                    valid_writer.add_summary(merged, i)
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                    logger.info('Fine-Tuning: Step %d, valid accuracy %g' % (i, accuracy))
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            loss, accuracy, _ = session.run([self.loss, self.accuracy, self.fine_tuning],
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                                            feed_dict={self.x: batch_x, self.y_: batch_y})
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            logger.info('Fine-Tuning: Step %d, batch accuracy %g, loss %g' % (i, accuracy, loss))
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            i += 1
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        if tuning_criterion == 'monitor_based':
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            tf.train.Saver().restore(session, tuning_summaries_dir + '/best.ckpt')
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        if summaries_dir is not None:
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            train_writer.close()
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            test_writer.close()
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            valid_writer.close()
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    def get_encode_loss(self, layer, x, y, session=None):
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        """Get encoder loss of layer specified
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        """
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        if session is None:
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            if self.sess is None:
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                session = tf.Session()
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                self.sess = session
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            else:
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                session = self.sess
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        return session.run(layer.encode_loss, feed_dict={self.x: x, self.y_: y})
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    def predict_accuracy(self, x, y, session=None):
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        """Get Accuracy given feature array and corresponding labels
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        """
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        if session is None:
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            if self.sess is None:
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                session = tf.Session()
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                self.sess = session
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            else:
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                session = self.sess
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        return session.run(self.accuracy, feed_dict={self.x: x, self.y_: y})
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    def predict_proba(self, x, session=None):
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        """Predict probability (Softmax)
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        """
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        if session is None:
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            if self.sess is None:
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                session = tf.Session()
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                self.sess = session
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            else:
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                session = self.sess
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        return session.run(self.y, feed_dict={self.x: x})
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    def predict(self, x, session=None):
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        if session is None:
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            if self.sess is None:
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                session = tf.Session()
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                self.sess = session
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            else:
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                session = self.sess
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        return session.run(self.y_class, feed_dict={self.x: x})
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