Function M-files.

  New functions may be added to MATLAB's vocabulary if they

  are expressed in terms of other existing functions. The 

  commands and functions that comprise the new function must

  be put in a file whose name defines the name of the new 

  function, with a filename extension of '.m'. At the top of

  the file must be a line that contains the syntax definition

  for the new function. For example, the existence of a file 

  on disk called STAT.M with:



          function [mean,stdev] = stat(x)

          n = length(x);

          mean = sum(x) / n;

          stdev = sqrt(sum((x - mean).^2)/n);



  defines a new function called STAT that calculates the 

  mean and standard deviation of a vector. The variables

  within the body of the function are all local variables.

  See SCRIPT1ERKKNC for procedures that work globally on the work-