MATLAB Compiler

Converting Script M-Files to Function M-Files

MATLAB provides two ways to package sequences of MATLAB commands:

• Function M-files
• Script 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 function is usually fairly simple. To convert a script to a function, simply add a function line at the top of the M-file.

For example, consider the script M-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-file from a 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 in the MATLAB workspace. If it is important to have m accessible from the MATLAB workspace, you can change the beginning of the function to

• function [m,t] = houdini
  

Specifying S-Function Characteristics

Stand-Alone Applications