Linear Algebra with Applications, 10th Edition

M-files

It is possible to extend MATLAB by adding your own programs. MATLAB programs are all given the extension .m and are referred to as M-files. There are two basic types of M-files.

Script Files

Script files are files that contain a series of MATLAB commands. All the variables used in these commands are global, and consequently the values of these variables in your MATLAB session will change every time you run the script file. For example, if you wanted to determine the nullity of a matrix, you could create a script file nullity.m containing the following commands:

$$\begin{array}{cc}\hfill \mathsf{\left[}\mathsf{\text{m}}\mathsf{,}\mathsf{\text{n}}\mathsf{\right]}& =\mathsf{\text{size}}\left(A\right)\hfill \\ \hfill \mathsf{\text{nuldim}}& =\mathsf{\text{n}}-\mathsf{\text{rank}}\left(A\right)\hfill \end{array}$$

Entering the command nullity would cause the two lines of code in the script file to be executed. The disadvantage of determining the nullity ...