GNU Octave is an open source and free alternative to run MATLAB code.

You can download Octave from here. Version 4.0.0 is the latest release; however, versions 3.8.x still work well for the course. 

For the download follow the related instructions according to your operating system (including Linux, Mac OS X and Windows).

If you are a Microsoft Windows user and want to get the latest release, an official Windows binary installer is available.

If you are a Mac OS X user, follow these instructions.

Below, you can find some notes to install Octave on Mac OS X using a package manager (see the Octave's Wiki for details). 

Before you start, estimate that the entire installation process can take a few hours. 

1) As first step, you have to download and install XCode via the Mac App Store.

Once installed, then you have to install the XCode Command Line Tools by running the command xcode-select --install from a Terminal.

You also have to run sudo xcodebuild -license after doing this. 

2) Then, as second step, you have to download and install a package manager. 

There are three package managers which support Octave. They are Fink, Macports, and Homebrew.

At the present time, Fink provides the most reliable means of installing Octave on Mac OS X. 

Follow the instructions on the Octave's Wiki for installing first Fink and then Octave.