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comparison scripts/statistics/base/studentize.m @ 4885:28ab079d8f0e

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[project @ 2004-04-30 04:21:33 by jwe]
author jwe
date Fri, 30 Apr 2004 04:21:33 +0000
parents 22bd65326ec1
children 54b076a24718
comparison
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4884:a9f67193e3a0 4885:28ab079d8f0e
16 ## along with Octave; see the file COPYING. If not, write to the Free 16 ## along with Octave; see the file COPYING. If not, write to the Free
17 ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA 17 ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA
18 ## 02111-1307, USA. 18 ## 02111-1307, USA.
19 19
20 ## -*- texinfo -*- 20 ## -*- texinfo -*-
21 ## @deftypefn {Function File} {} studentize (@var{x}) 21 ## @deftypefn {Function File} {} studentize (@var{x}, @var{dim})
22 ## If @var{x} is a vector, subtract its mean and divide by its standard 22 ## If @var{x} is a vector, subtract its mean and divide by its standard
23 ## deviation. 23 ## deviation.
24 ## 24 ##
25 ## If @var{x} is a matrix, do the above for each column. 25 ## If @var{x} is a matrix, do the above along the first non-singleton
26 ## dimension. If the optional argument @var{dim} is given then operate
27 ## along this dimension.
26 ## @end deftypefn 28 ## @end deftypefn
27 29
28 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> 30 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
29 ## Description: Subtract mean and divide by standard deviation 31 ## Description: Subtract mean and divide by standard deviation
30 32
31 function t = studentize (x) 33 function t = studentize (x, dim)
32 34
33 if (nargin != 1) 35 if (nargin != 1 && nargin != 2)
34 usage ("studentize (x)"); 36 usage ("studentize (x, dim)");
35 endif 37 endif
36 38
37 if isvector (x) 39 nd = ndims (x);
38 if (std (x) == 0) 40 sz = size (x);
39 t = zeros (size (x)); 41 if (nargin != 2)
40 else 42 %% Find the first non-singleton dimension
41 t = (x - mean (x)) / std (x); 43 dim = 1;
44 while (dim < nd + 1 && sz (dim) == 1)
45 dim = dim + 1;
46 endwhile
47 if (dim > nd)
48 dim = 1;
42 endif 49 endif
43 elseif ismatrix (x)
44 l = ones (rows (x), 1);
45 t = x - l * mean (x);
46 t = t ./ (l * max ([(std (t)); (! any (t))]));
47 else 50 else
51 if (! (isscalar (dim) && dim == round (dim)) && dim > 0 &&
52 dim < (nd + 1))
53 error ("studentize: dim must be an integer and valid dimension");
54 endif
55 endif
56
57 if (! ismatrix (x))
48 error ("studentize: x must be a vector or a matrix"); 58 error ("studentize: x must be a vector or a matrix");
49 endif 59 endif
50 60
61 c = sz (dim);
62 idx = ones (1, nd);
63 idx (dim) = c;
64 t = x - repmat (mean (x, dim), idx);
65 t = t ./ repmat (max (cat (dim, std(t, [], dim), ! any (t, dim)), [], dim), idx);
66
51 endfunction 67 endfunction