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1 ## Copyright (C) 1995, 1996, 1997 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 2, or (at your option) |
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8 ## 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, write to the Free |
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17 ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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18 ## 02110-1301, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} center (@var{x}) |
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22 ## @deftypefnx {Function File} {} center (@var{x}, @var{dim}) |
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23 ## If @var{x} is a vector, subtract its mean. |
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24 ## If @var{x} is a matrix, do the above for each column. |
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25 ## If the optional argument @var{dim} is given, perform the above |
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26 ## operation along this dimension |
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27 ## @end deftypefn |
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28 |
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29 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> |
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30 ## Description: Center by subtracting means |
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31 |
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32 function retval = center (x, varargin) |
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33 |
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34 if (nargin != 1 && nargin != 2) |
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35 usage ("center (x)"); |
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36 endif |
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37 |
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38 if (isvector (x)) |
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39 retval = x - mean (x, varargin{:}); |
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40 elseif (ismatrix (x)) |
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41 if nargin < 2 |
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42 dim = min (find (size (x) > 1)); |
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43 if isempty (dim), |
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44 dim=1; |
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45 endif; |
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46 else |
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47 dim = varargin {1}; |
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48 endif |
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49 sz = ones (1, ndims (x)); |
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50 sz (dim) = size (x, dim); |
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51 retval = x - repmat (mean (x, dim), sz); |
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52 elseif (isempty (x)) |
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53 retval = x; |
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54 else |
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55 error ("center: x must be a vector or a matrix"); |
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56 endif |
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57 |
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58 endfunction |
