MATLAB PROGRAMMING TIPS

SHAMEER A KOYA

MATLAB Scripts

Script

MATLAB Script or programs are sequences of MATLAB commands saved in plain text files.

MATLAB requires that these files have the extension ‘.m’.

When you type the name of the script file at the MATLAB prompt the commands in the script file are executed as if you had typed them in command window.

Why use Scripts? Use same code in more than one place in program without

rewriting code Reuse code by calling in different programs

Code for a script is done in an Editor window and saved as m-file.

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Typing a Program

If you are using the command prompt, type edit in the command prompt.

This will open the editor. You can directly type edit and then the filename

(with .m extension)Alternatively, if you are using the IDE, choose NEW

-> Script. This also opens the editor and creates a file named

Untitled. You can name and save the file after typing the

code.

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Opening A Script file4

Sample Script5

Run the Script

After creating and saving the file, you can run it in two ways: Clicking the Run button on the editor window Just typing the filename in the command prompt.

When typing the filename in the command window do not include ".m".

In case your code has errors, MATLAB will show an error message in the command window, when you try to run the program .

Error message will be hyperlinked to the line in the file that caused the error.

Interpret the error message and make necessary changes to you code in the editor.

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Run the Script …7

Special Note

Apart from syntax errors, perhaps the most common problem with using script files is that MATLAB cannot locate the script file you wish to execute.

MATLAB gives the error message??? Undefined function or variable ...

It is not immediately clear why the function is undefined when its m-file is clearly visible to the user.

MATLAB cannot execute a function unless it knows where to find its m-file.

This requires that the function be in the internal MATLAB path.

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Script variables are Global !!

Script variables are added to the workspace.If you use the same variables in another

script, they will be modified by that script.This may result in a confusing mix of

variables in the MATLAB workspace.Some times it may lead to a syntax error or

may lead to subtle errors in the result.

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