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Deep Learning with Theano

You're reading from   Deep Learning with Theano Perform large-scale numerical and scientific computations efficiently

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Product type Paperback
Published in Jul 2017
Publisher Packt
ISBN-13 9781786465825
Length 300 pages
Edition 1st Edition
Tools
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Author (1):
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Christopher Bourez Christopher Bourez
Author Profile Icon Christopher Bourez
Christopher Bourez
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Table of Contents (15) Chapters Close

Preface 1. Theano Basics FREE CHAPTER 2. Classifying Handwritten Digits with a Feedforward Network 3. Encoding Word into Vector 4. Generating Text with a Recurrent Neural Net 5. Analyzing Sentiment with a Bidirectional LSTM 6. Locating with Spatial Transformer Networks 7. Classifying Images with Residual Networks 8. Translating and Explaining with Encoding – decoding Networks 9. Selecting Relevant Inputs or Memories with the Mechanism of Attention 10. Predicting Times Sequences with Advanced RNN 11. Learning from the Environment with Reinforcement 12. Learning Features with Unsupervised Generative Networks 13. Extending Deep Learning with Theano Index

Continuous Bag of Words model


The design of the neural network to predict a word given its surrounding context is shown in the following figure:

The input layer receives the context while the output layer predicts the target word. The model we'll use for the CBOW model has three layers: input layer, hidden layer (also called the projection layer or embedding layer), and output layer. In our setting, the vocabulary size is V and the hidden layer size is N. Adjacent units are fully connected.

The input and the output can be represented either by an index (an integer, 0-dimensional) or a one-hot-encoding vector (1-dimensional). Multiplying with the one-hot-encoding vector v consists simply of taking the j-th row of the embedding matrix:

Since the index representation is more efficient than the one-hot encoding representation in terms of memory usage, and Theano supports indexing symbolic variables, it is preferable to adopt the index representation as much as possible.

Therefore, input (context...

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