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1 # Copyright (C) 1993 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 the |
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7 # Free Software Foundation; either version 2, or (at your option) any |
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8 # later version. |
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9 # |
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10 # Octave is distributed in the hope that it will be useful, but WITHOUT |
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11 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 # FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 # 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, 675 Mass Ave, Cambridge, MA 02139, USA. |
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18 |
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4
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19 function retval = median (a) |
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20 |
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21 # usage: median (a) |
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22 # |
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23 # For vector arguments, return the median of the values. |
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24 # |
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25 # For matrix arguments, return a row vector containing the median for |
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26 # each column. |
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27 # |
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28 # See also: std, mean |
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29 |
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30 if (nargin != 1) |
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31 error ("usage: medain (a)"); |
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32 endif |
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33 |
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34 [nr, nc] = size (a); |
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35 s = sort (a); |
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36 if (nr == 1 && nc > 0) |
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37 if (rem (nc, 2) == 0) |
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38 i = nc/2; |
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39 retval = (s (i) + s (i+1)) / 2; |
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40 else |
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41 i = ceil (nc/2); |
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42 retval = s (i); |
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43 endif |
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44 elseif (nr > 0 && nc > 0) |
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45 if (rem (nr, 2) == 0) |
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46 i = nr/2; |
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47 retval = (s (i,:) + s (i+1,:)) / 2; |
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48 else |
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49 i = ceil (nr/2); |
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50 retval = s (i,:); |
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51 endif |
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52 else |
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53 error ("median: invalid matrix argument"); |
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54 endif |
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55 |
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56 endfunction |
