07 – January 31

Writing functions in MATLAB

• All function must have the following line as the first line of code
  • function res = funcName(input1, input2, …)
    • where res is the output and can be multiple outputs ([res1, res2, …])
      • you can also return multiple variables in a structure, these variable can be of different types, e.g.,
        • res.val1 (integer)
        • res.val2 (cell)
        • res.val3 (string)
    • where funcName is the name of the function
      • don’t name functions the same as built-in MATLAB functions, as it will render these functions inaccessible – MATLAB will generate a warning on start-up if you have a naming conflict
    • where (input1, input2, …) is the list of the inputted variable
      • regardless of what the inputted variable are named when the function is called, they are always referred to by the names defined in (input1, input2, …) within the function
  • Name your file ‘funcName.m’
  • It is useful to also include a comment header with your function, this is the information that will print out when you type ‘help funcName’
  • You can have multiple functions in a file which is useful if there is a routine in your function that is repeated but isn’t particularly general
    • To do this you would type ‘end’ after the code for the main function and then type ‘function res = suFuncName(input1, input2, …)’ on a new line
  • More details (and examples) about functions are available in the MATLAB help documentation.