Creating nonlinear neural network and finding the Jacobian matrix of its funciton

The next step towards finding loss function of a neural network is to extend the results we found here to add a bias to the linear function, i.e., creating $W^{\top}x+b$ where $x \in \mathbb{R}^n$, $b \in \mathbb{R}^m$, and $W \in \mathbb{R}^{n \times m}$. This can be done easily because…

By S. M. Saeed Damadi

Linear neural network to creat $f(x)= W^{\top}x$

Goal:In this post we are going to go through the very first step that help us to suppress algebraic notations for representing the function calculating by a fully connected neural network. Following this step helps you to master shorthand notations to express operations happening in…

By S. M. Saeed Damadi

What is Jacobian matrix of $f(x)= Ax$?

In this short post we are going to find the Jacobian matrix of $f(x)= Ax$ where $f: \mathbb{R}^n \rightarrow \mathbb{R}^m$, $x \in \mathbb{R}^n$, and $A \in \mathbb{R}^{m \times n}$. As I explained here, in order to find the Jacobian matrix we need a vector-valued function…

By S. M. Saeed Damadi

What is Jacobian matrix and why do we need it?

Derivative of univariate functionTo understand what is Jacobian, we need to revisit the derivative of a univariate function wherein $f$ maps the real line into the real line, that is, $f: \mathbb{R} \rightarrow \mathbb{R} $. The derivative of $f$ denoted by $f'$ measures the sensitivity to change…

By S. M. Saeed Damadi

Jacobian matrix of a composite function

This post is the continuation of what I have discussed here to clarify what is Jacobian matrix. We are going to see an example in which Jacobian matrix is being applied on a composite function including two functions. This case is very intuitive since it…

By S. M. Saeed Damadi