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maint: update copyright notices for 2012
author John W. Eaton <jwe@octave.org>
date Mon, 02 Jan 2012 14:25:41 -0500
parents 6b2f14af2360
children 938a8d792c37
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1 ## Copyright (C) 1995-2012 Kurt Hornik
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2 ##
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3 ## This file is part of Octave.
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4 ##
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5 ## Octave is free software; you can redistribute it and/or modify it
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6 ## under the terms of the GNU General Public License as published by
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7 ## the Free Software Foundation; either version 3 of the License, or (at
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8 ## your option) any later version.
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9 ##
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10 ## Octave is distributed in the hope that it will be useful, but
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 ## General Public License for more details.
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14 ##
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15 ## You should have received a copy of the GNU General Public License
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16 ## along with Octave; see the file COPYING. If not, see
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17 ## <http://www.gnu.org/licenses/>.
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18
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19 ## -*- texinfo -*-
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20 ## @deftypefn {Function File} {} zscore (@var{x})
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21 ## @deftypefnx {Function File} {} zscore (@var{x}, @var{dim})
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22 ## If @var{x} is a vector, subtract its mean and divide by its standard
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23 ## deviation.
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24 ##
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25 ## If @var{x} is a matrix, do the above along the first non-singleton
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26 ## dimension.
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27 ## If the optional argument @var{dim} is given, operate along this dimension.
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28 ## @seealso{center}
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29 ## @end deftypefn
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30
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31 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
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32 ## Description: Subtract mean and divide by standard deviation
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33
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34 function z = zscore (x, dim)
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35
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36 if (nargin != 1 && nargin != 2)
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37 print_usage ();
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38 endif
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39
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40 if (! (isnumeric (x) || islogical (x)))
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41 error ("zscore: X must be a numeric vector or matrix");
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42 endif
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43
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44 nd = ndims (x);
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45 sz = size (x);
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46 if (nargin != 2)
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47 ## Find the first non-singleton dimension.
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48 (dim = find (sz > 1, 1)) || (dim = 1);
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49 else
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50 if (!(isscalar (dim) && dim == fix (dim))
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51 || !(1 <= dim && dim <= nd))
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52 error ("zscore: DIM must be an integer and a valid dimension");
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53 endif
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54 endif
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55
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56 n = sz(dim);
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57 if (n == 0)
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58 z = x;
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59 else
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60 x = center (x, dim); # center also promotes integer to double for next line
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61 z = zeros (sz, class (x));
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62 s = std (x, [], dim);
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63 s(s==0) = 1;
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64 z = bsxfun (@rdivide, x, s);
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65 endif
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66
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67 endfunction
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68
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69
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70 %!assert(zscore ([1,2,3]), [-1,0,1])
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71 %!assert(zscore (single([1,2,3])), single([-1,0,1]))
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72 %!assert(zscore (int8([1,2,3])), [-1,0,1])
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73 %!assert(zscore (ones (3,2,2,2)), zeros (3,2,2,2))
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74 %!assert(zscore ([2,0,-2;0,2,0;-2,-2,2]), [1,0,-1;0,1,0;-1,-1,1])
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75
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76 %% Test input validation
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77 %!error zscore ()
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78 %!error zscore (1, 2, 3)
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79 %!error zscore (['A'; 'B'])
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80 %!error zscore (1, ones(2,2))
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81 %!error zscore (1, 1.5)
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82 %!error zscore (1, 0)
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83 %!error zscore (1, 3)
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84