Book Image

Python Machine Learning - Third Edition

By : Sebastian Raschka, Vahid Mirjalili
5 (1)
Book Image

Python Machine Learning - Third Edition

5 (1)
By: Sebastian Raschka, Vahid Mirjalili

Overview of this book

Python Machine Learning, Third Edition is a comprehensive guide to machine learning and deep learning with Python. It acts as both a step-by-step tutorial, and a reference you'll keep coming back to as you build your machine learning systems. Packed with clear explanations, visualizations, and working examples, the book covers all the essential machine learning techniques in depth. While some books teach you only to follow instructions, with this machine learning book, Raschka and Mirjalili teach the principles behind machine learning, allowing you to build models and applications for yourself. Updated for TensorFlow 2.0, this new third edition introduces readers to its new Keras API features, as well as the latest additions to scikit-learn. It's also expanded to cover cutting-edge reinforcement learning techniques based on deep learning, as well as an introduction to GANs. Finally, this book also explores a subfield of natural language processing (NLP) called sentiment analysis, helping you learn how to use machine learning algorithms to classify documents. This book is your companion to machine learning with Python, whether you're a Python developer new to machine learning or want to deepen your knowledge of the latest developments.
Table of Contents (21 chapters)
20
Index

TensorFlow Variable objects for storing and updating model parameters

We covered Tensor objects in Chapter 13, Parallelizing Neural Network Training with TensorFlow. In the context of TensorFlow, a Variable is a special Tensor object that allows us to store and update the parameters of our models during training. A Variable can be created by just calling the tf.Variable class on user-specified initial values. In the following code, we will generate Variable objects of type float32, int32, bool, and string:

>>> a = tf.Variable(initial_value=3.14, name='var_a')
>>> print(a)
<tf.Variable 'var_a:0' shape=() dtype=float32, numpy=3.14>
>>> b = tf.Variable(initial_value=[1, 2, 3], name='var_b')
>>> print(b)
<tf.Variable 'var_b:0' shape=(3,) dtype=int32, numpy=array([1, 2, 3], dtype=int32)>
>>> c = tf.Variable(initial_value=[True, False], dtype=tf.bool)
>>> print(c)
<tf.Variable...