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1 ## Copyright (C) 1996 John W. Eaton |
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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, 59 Temple Place - Suite 330, Boston, MA |
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18 ## 02111-1307, USA. |
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19 |
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20 ## usage: median (a) |
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21 ## |
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22 ## For vector arguments, return the median of the values. |
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23 ## |
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24 ## For matrix arguments, return a row vector containing the median for |
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25 ## each column. |
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26 ## |
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27 ## See also: std, mean |
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28 |
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29 ## Author: jwe |
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30 |
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31 function retval = median (a) |
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32 |
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33 if (nargin != 1) |
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34 usage ("median (a)"); |
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4
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35 endif |
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36 |
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37 [nr, nc] = size (a); |
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38 s = sort (a); |
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39 if (nr == 1 && nc > 0) |
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40 if (rem (nc, 2) == 0) |
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41 i = nc/2; |
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42 retval = (s (i) + s (i+1)) / 2; |
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43 else |
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44 i = ceil (nc/2); |
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45 retval = s (i); |
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46 endif |
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47 elseif (nr > 0 && nc > 0) |
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48 if (rem (nr, 2) == 0) |
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49 i = nr/2; |
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50 retval = (s (i,:) + s (i+1,:)) / 2; |
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51 else |
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52 i = ceil (nr/2); |
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53 retval = s (i,:); |
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54 endif |
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55 else |
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56 error ("median: invalid matrix argument"); |
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57 endif |
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58 |
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59 endfunction |
