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Converting Script M-Files to Function M-Files

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Converting Script M-Files to Function M-Files

MATLAB provides two ways to package sequences of MATLAB commands:

•Function M-files

•S cript M - files

These two categories of M -files differ in two important respects:

•You can pass arguments to function M-files but not to script M-files.

•Variables used inside function M-files are local to that function; you cannot

access these variables from the MATLAB interpreter’s workspace unless

they are passed back by the function. By contrast, variables used inside

script M-files are shared with the caller’s workspace; you can access these

variables from the MATLAB interpreter command line.

The MATLAB Compiler cannot compile script M-files nor can it compile a

function M-file that calls a script.

Converting a script into a funct ion is usually fairly simple. To convert a script

to a function, simply add a

function line at the top of the M- file.

Forexample,considerthescriptM-file

houdini.m.

m = magic(4); % Assign 4x4 matrix to m.

t = m .^ 3; % Cube each element of m.

disp(t); % Display the value of t.

Running this script M-filefroma MATLAB session creates variables m and t in

your MATLAB workspace.

The MATLAB Compiler cannot compile

houdini.m because houdini.m is a

script. Convert this script M-file into a function M-file by simply adding a

function header line.

function [m,t] = houdini(sz)

m = magic(sz); % Assign matrix to m.

t = m .^ 3; % Cube each element of m.

disp(t) % Display the value of t.

The MATLAB Compiler can now compile houdini.m. However, because this

makes

houdini a function, running houdini.mex no longer creates variable m

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MATLAB COMPILER RELEASE NOTES Guide de l'utilisateur Page 69