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annotate scripts/statistics/base/mean.m @ 3265:a2b3a1413d28

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[project @ 1999-09-03 02:53:03 by jwe]
author jwe
date Fri, 03 Sep 1999 02:53:10 +0000
parents 781c930425fd
children 0748b03c3510
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1 ## Copyright (C) 1995, 1996, 1997 Kurt Hornik
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2 ##
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3 ## This program is free software; you can redistribute it and/or modify
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4 ## it under the terms of the GNU General Public License as published by
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5 ## the Free Software Foundation; either version 2, or (at your option)
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6 ## any later version.
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7 ##
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8 ## This program is distributed in the hope that it will be useful, but
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9 ## WITHOUT ANY WARRANTY; without even the implied warranty of
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10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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11 ## General Public License for more details.
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12 ##
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13 ## You should have received a copy of the GNU General Public License
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14 ## along with this file. If not, write to the Free Software Foundation,
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15 ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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16
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17 ## usage: mean (x [, opt])
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18 ##
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19 ## For vector arguments, return the mean the values.
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20 ## For matrix arguments, return a row vector containing the mean for
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21 ## each column.
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22 ##
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23 ## With the optional argument opt, the kind of mean computed can be
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24 ## selected.
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25 ## If opt is "a", the (ordinary) arithmetic mean is computed. This
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26 ## is the default.
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27 ## If opt is "g", the geometric mean is computed.
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28 ## If opt is "h", the harmonic mean is computed.
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29
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30 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at>
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31 ## Description: Compute arithmetic, geometric, and harmonic mean
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32
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33 function y = mean (x, opt)
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34
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35 if ((nargin < 1) || (nargin > 2))
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36 usage ("mean (x [, opt])");
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37 endif
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38
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39 if isempty (x)
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40 error ("mean: x must not be empty");
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41 endif
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42
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43 if (rows (x) == 1)
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44 x = x.';
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45 endif
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46
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47 if (nargin == 1)
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48 opt = "a";
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49 endif
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50
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51 [r, c] = size (x);
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52
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53 if (strcmp (opt, "a"))
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54 y = sum (x) / r;
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55 elseif (strcmp (opt, "g"))
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56 y = NaN * ones (1, c);
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57 i = find (all (x > 0));
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58 if any (i)
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59 y(i) = exp (sum (log (x(:, i))) / r);
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60 endif
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61 elseif (strcmp (opt, "h"))
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62 y = NaN * ones (1, c);
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63 i = find (all (x != 0));
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64 if any (i)
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65 y(i) = r ./ sum (1 ./ x(:, i));
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66 endif
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67 else
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68 error (sprintf ("mean: option `%s' not recognized", opt));
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69 endif
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70
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71 endfunction