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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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View Code Duplication |
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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View Code Duplication |
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(logits=self.output_layer.logits, labels=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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View Code Duplication |
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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_ = session.run(self.encode_opts[j], feed_dict={self.x: batch_x, self.y_: batch_y}) |
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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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View Code Duplication |
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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_ = session.run(self.fine_tuning, feed_dict={self.x: batch_x, self.y_: batch_y}) |
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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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