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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 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 MLP: |
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"""Multi-Layer Perceptron |
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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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activation_fn: activation function used in hidden layer. |
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optimizer: Optimizer used for updating weights. |
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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 inner hidden layers. |
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summaries (:obj:`list`): List of tensorflow summaries. |
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output_layer: Output softmax layer for multi-class classification, sigmoid for binary classification |
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y (:obj:`tensorflow.Tensor`): Softmax/Sigmoid output layer output tensor. |
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y_class (:obj:`tensorflow.Tensor`): Tensor to get class label from output layer. |
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loss (:obj:`tensorflow.Tensor`): Tensor that represents the cross-entropy loss. |
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correct_prediction (:obj:`tensorflow.Tensor`): Tensor that represents the correctness of classification result. |
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accuracy (:obj:`tensorflow.Tensor`): Tensor that represents the accuracy of the classifier (exact matching |
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ratio in multi-class classification) |
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optimizer: Optimizer used for updating weights. |
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fit_step (:obj:`tensorflow.Tensor`): Tensor to update weights based on the optimizer algorithm provided. |
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sess: Tensorflow session. |
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merged: Merged summaries. |
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""" |
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def __init__(self, num_features, num_classes, layers, activation_fn=tf.sigmoid, 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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# 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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HiddenLayer(num_features, layers[i], x=self.x, name=('Hidden%d' % i), activation_fn=activation_fn) |
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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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HiddenLayer(layers[i-1], layers[i], x=self.inner_layers[i-1].y, |
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name=('Hidden%d' % i), activation_fn=activation_fn) |
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) |
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self.summaries += self.inner_layers[i].summaries |
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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(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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if optimizer is None: |
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self.optimizer = tf.train.AdamOptimizer() |
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else: |
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self.optimizer = optimizer |
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with tf.name_scope('train'): |
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self.fit_step = self.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, iter_num=100, |
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summaries_dir=None, summary_interval=100, |
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test_x=None, test_y=None, |
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session=None, criterion='const_iteration'): |
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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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iter_num (:obj:`int`): Number of training iterations for const iterations, step depth for monitor based |
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stopping criterion. |
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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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criterion (:obj:`str`): Stopping criteria. 'const_iterations' or 'monitor_based' |
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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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if summaries_dir is not None: |
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train_writer = tf.summary.FileWriter(summaries_dir + '/train') |
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test_writer = tf.summary.FileWriter(summaries_dir + '/test') |
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valid_writer = tf.summary.FileWriter(summaries_dir + '/valid') |
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session.run(tf.global_variables_initializer()) |
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# Get Stopping Criterion |
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View Code Duplication |
if criterion == 'const_iteration': |
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criterion = ConstIterations(num_iters=iter_num) |
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elif 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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x = x[0:num_samples-valid_set_len, :] |
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y = y[0:num_samples-valid_set_len, :] |
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_criterion = MonitorBased(n_steps=iter_num, |
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monitor_fn=self.predict_accuracy, 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, summaries_dir + '/best.ckpt')) |
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else: |
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logger.error('Wrong criterion %s specified.' % criterion) |
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return |
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# Setup batch injector |
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injector = BatchInjector(data_x=x, data_y=y, batch_size=batch_size) |
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i = 0 |
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train_accuracy = 0 |
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while _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: x, self.y_: y}) |
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train_writer.add_summary(summary, i) |
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train_accuracy = accuracy |
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logger.info('Step %d, train_set 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('test_set accuracy %g' % accuracy) |
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if 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('valid_set accuracy %g' % accuracy) |
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loss, accuracy, _ = session.run([self.loss, self.accuracy, self.fit_step], |
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feed_dict={self.x: batch_x, self.y_: batch_y}) |
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#logger.info('Step %d, training accuracy %g, loss %g' % (i, accuracy, loss)) |
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#_ = session.run(self.fit_step, feed_dict={self.x: batch_x, self.y_: batch_y}) |
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#logger.info('Step %d, training accuracy %g, loss %g' % (i, accuracy, loss)) |
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i += 1 |
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tf.train.Saver().restore(session, summaries_dir + '/best.ckpt') |
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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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