## Copyright (C) 1995, 1996, 1997  Kurt Hornik
## 
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2, or (at your option)
## any later version.
## 
## This program is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details. 
## 
## You should have received a copy of the GNU General Public License
## along with this file.  If not, write to the Free Software Foundation,
## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

## usage:  values (x)
##
## Return the different values in a column vector, arranged in ascending
## order.
  
## Author:  KH <Kurt.Hornik@ci.tuwien.ac.at>
## Description:  Extract unique elements

function v = values (x)
  
  if (nargin != 1)
    usage ("values (x)");
  endif
  
  if !(is_vector (x))
    error ("values:  x must be a vector");
  endif

  i = any (isnan (x));
  x = x(find(!isnan (x)));	# HACK!
  n = length (x);
  x = reshape (x, n, 1);
  s = sort (x);
  v = s([1; find (s(2:n) > s(1:n-1)) + 1]);
  if (i)
    v = [v; NaN];
  endif

endfunction
