Scripts

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• Questions?
• Scripts
  • Sections 4.1, 4.2
    • Script = text document that Matlab can run
      • Scripts contain Matlab commands
      • “Run” = Matlab reads from file, so if you haven’t saved changes Matlab won’t see them
      • Suppressing output w/ “;”
      • File names must end with “.m”
    • Organizing scripts for readability
      • Comments: % and also %{ … %}
      • Blank lines
      • Multiple statements per line
  • Examples
    • Drivable distance (from book)
      

      % How far can you drive on a given amount of gas.
      gas = 12;    % Available gas in gallons
      mpg = 25;
      miles = gas * mpg

      • Note that you can run this (or any script) by clicking “Run” in the toolbar while the script is visible in the editor
    • Gravity (from book)
      

      % Force of gravity between 2 masses
      % F = G m1 m2 / d^2
      
      %% Define constants
      G = 6.67e-11;
      
      %% Set up a light person on the moon
      m1 = 50;
      m2 = 7.34767309e22;
      d = 1737400;
      
      %% Set up a normal-weight person on Earth
      m1 = 60;
      m2 = 5.97219e24;
      d = 6.38e6;
      
      %% Calculate force
      F = G * m1 * m2 / d^2

      • Each section, introduced by a %% comment, can be run individually by putting the cursor in it and then clicking the “Run Section” toolbar button
• Arithmetic Lab
  • Consider writing common sub-expressions (e.g., square root of b² - 4ac in quadratic equation) once, assigning the result to a variable, and then using that variable in the multiple places where the value is needed
  • Then if there’s a mistake in the expression you only have to fix it in one place, not in many
• Next
  • Variables
  • Read sections 3.1 - 3.4 in textbook
  • Optionally first 2 3/4 minutes of “Variables and Simple Arrays” video at http://www.see.ed.ac.uk/teaching/courses/matlab/unit01/variables-arrays.shtml

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