Writing Matlab Functions

• It is relatively easy to create your own Matlab functions. An example is included below:

  function y = simpfun(x, z)
  % SIMPFUN  An example Matlab function.
  %
  %   Y = SIMPFUN(X,Z) doesn't do much.  The Z parameter is optional
  %   and should either be a scalar or equal in size to X.
  %
  %   By Gary P. Scavone, McGill University, 2004.
  
  if nargin == 1
    z = 0;
  end
  
  if numel(z) ~= 1 && max(size(z) ~= size(x))
    error('Simpfun: Parameter Z size error.');
  end
  
  y = 0.5.*x + z;
  

• Well designed Matlab functions will check argument values and sizes to avoid undefined conditions.

• Example Matlab function: simpfun.m