Octave：替代Matlab的免费数值计算工具

Octave是一个免费的数值计算软件，可以作为免费版本的Matlab用，但功能没有Matlab多。在机器学习课程里会用到它。
下面是摘自官方的介绍：
GNU Octave is a high-level interpreted language, primarily intended for numerical computations. It provides capabilities for the numerical solution of linear and nonlinear problems, and for performing other numerical experiments. It also provides
extensive graphics capabilities for data visualization and manipulation. Octave is normally used through its interactive command line interface, but it can also be used to write non-interactive programs. The Octave language is quite similar to Matlab so that
most programs are easily portable.
 
参考资料：
1. http://www.gnu.org/software/octave/