Book Image

Deep Learning from the Basics

By : Koki Saitoh
5 (1)
Book Image

Deep Learning from the Basics

5 (1)
By: Koki Saitoh

Overview of this book

Deep learning is rapidly becoming the most preferred way of solving data problems. This is thanks, in part, to its huge variety of mathematical algorithms and their ability to find patterns that are otherwise invisible to us. Deep Learning from the Basics begins with a fast-paced introduction to deep learning with Python, its definition, characteristics, and applications. You’ll learn how to use the Python interpreter and the script files in your applications, and utilize NumPy and Matplotlib in your deep learning models. As you progress through the book, you’ll discover backpropagation—an efficient way to calculate the gradients of weight parameters—and study multilayer perceptrons and their limitations, before, finally, implementing a three-layer neural network and calculating multidimensional arrays. By the end of the book, you’ll have the knowledge to apply the relevant technologies in deep learning.
Table of Contents (11 chapters)

Identity Function and Softmax Function

An identity function outputs the input as it is. The function that outputs what is entered without doing anything is an identity function. Therefore, when an identity function is used for the output layer, an input signal is returned as-is. Using the diagram of the neural network we've used so far, you can represent the process by an identity function as shown in Figure 3.21. The process of conversion by the identity function can be represented with one arrow, in the same way in the same way as the activation function we have seen so far:

Figure 3.21: Identity function

The softmax function, which is used for a classification problem, is expressed by the following equation:

16

(3.10)

exp(x) is an exponential function that indicates ex (e is Napier's constant, 2.7182…). Assuming...