 Usage:  yh = lowess (x, y{, f})  
 
 Input:

  x                      n x 1 vector 
                         
  y                      n x 1 vector 
                         
  f                      scalar 
                         
 Output:

  yh                     n x 1 vector 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
