Tips on Matlab

Some tips on using Matlab.

The first five tips are for those using Matlab on the PCs located in the College of Engineering Building, FAMU/FSU. (Note: You must have a unix account in the college of engineering to access Matlab here!)

Start the PC and activate Windows if it is not already activated.
Find the Matlab icon and start it by double-clicking on the icon. This will open up the Matlab command window.
The Matlab prompt is given by a pair of `greater than' signs i.e.
```
>>
```
At this prompt, you can type any of the Matlab built-in functions or toolbox commands or even your own functions or programs (also called scripts).
Any functions or scripts that you define have to be located only in your directory. In order to access your directory, type
```
cd f:
```
at the prompt. This will connect you to your Unix home directory!
To see the files and sub-directories in your home directory, type
```
dir
```
at the prompt. You will be able to see only those files whose names are upto eight characters long and whose extensions are upto three characters long. (Eg. hello.txt , matlab.hw , ECH4323 )
Always remember that your own files are to be stored in your Unix home directory.

If you are interested in buying Matlab for yourself, go to http://www.mathworks.com and check it out...

The following tips are for all first time users of Matlab. (Note: It is assumed that you are located in the correct directory.)

If you are using Matlab for the first time, it is strongly recommended that you go through the Matlab features by typing
```
expomap
```
at the prompt. This will take you through a series of step-by-step instructions on using Matlab. Once you go through this, you will be able to make your own function and script files.
To make your own function and script files,
- Go to the File menu in the Matlab window.
- Choose New.
- Choose M-file.
This will open up a Notepad window where you can start typing your Matlab functions or scripts.
To make a script file, type your set of instructions in the Notepad window. Save this file with a `.m' extension.
(Important: All Matlab function and script files must have a `.m' extension. For example, hello.m , prog1.m , hw1.m and so on ...)
Let us take an example from assignment #3, problem 1.a). You are required to find the determinant, the inverse and the eigenvalues of the matrix given by
```
1 2

3 4
```
The solution is given in this sample called hw3pb1a.m. You can save this file in your directory as follows:
- Click on hw3pb1a.m so that you see the Matlab set of instructions in Netscape.
- Click on the File menu in the Netscape browser.
- Click on the Save as... option.
- Select the correct directory and save the file as hw3pb1a.m.
Now, in order to run this script file, go back to the Matlab command window. At the prompt, type
```
hw3pb1a
```
This should give an output that looks like this...
```
Determinant

d =

    -2

Inverse

b =

   -2.0000    1.0000
    1.5000   -0.5000

Eigenvalues

e =

   -0.3723
    5.3723

>>
```
The procedure for making a function file is similar to that of a script file except that the function file
- The name of the function file should be the same as the name of the function itself.
This may be explained by an illustrative example. Look at this file called sqr.m. Save it in your directory as `sqr.m'. Go to the Matlab command window and try out some simple commands with the function `sqr'. Examples:
1. ```
>> sqr(4)

ans =

    16

>> 
```
2. ```
>> a=[1 2 3 4];
>> b=sqr(a) 

b =

     1     4     9    16

>> 
```
3. ```
>> a=[1 2;3 4];
>> sqr(a)

ans =

     1     4
     9    16

>> 
```