Programming and Data Types

Scripts

Scripts are the simplest kind of M-file because they have no input or output arguments. They're useful for automating series of MATLAB commands, such as computations that you have to perform repeatedly from the command line. Scripts operate on existing data in the workspace, or they can create new data on which to operate. Any variables that scripts create remain in the workspace after the script finishes so you can use them for further computations.

Simple Script Example

These statements calculate rho for several trigonometric functions of theta, then create a series of polar plots.

• % An M-file script to produce       % Comment lines
  % "flower petal" plots 
  theta = -pi:0.01:pi;                % Computations
  rho(1,:) = 2*sin(5*theta).^2;
  rho(2,:) = cos(10*theta).^3;
  rho(3,:) = sin(theta).^2;
  rho(4,:) = 5*cos(3.5*theta).^3;
  for k = 1:4
      polar(theta,rho(k,:))           % Graphics output
      pause
  end
  

Try entering these commands in an M-file called petals.m. This file is now a MATLAB script. Typing petals at the MATLAB command line executes the statements in the script.

After the script displays a plot, press Return to move to the next plot. There are no input or output arguments; petals creates the variables it needs in the MATLAB workspace. When execution completes, the variables (i, theta, and rho) remain in the workspace. To see a listing of them, enter whos at the command prompt.

Creating M-Files: Accessing Text Editors

Functions