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1 ## Copyright (C) 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} {} discrete_pdf (@var{x}, @var{v}, @var{p}) |
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22 ## For each element of @var{x}, compute the probability density function |
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23 ## (PDF) at @var{x} of a univariate discrete distribution which assumes |
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24 ## the values in @var{v} with probabilities @var{p}. |
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25 ## @end deftypefn |
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26 |
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27 ## Author: KH <Kurt.Hornik@wu-wien.ac.at> |
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28 ## Description: pDF of a discrete distribution |
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29 |
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30 function pdf = discrete_pdf (x, v, p) |
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31 |
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32 if (nargin != 3) |
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33 print_usage (); |
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34 endif |
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35 |
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36 sz = size (x); |
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37 |
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38 if (! isvector (v)) |
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39 error ("discrete_pdf: v must be a vector"); |
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40 elseif (! isvector (p) || (length (p) != length (v))) |
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41 error ("discrete_pdf: p must be a vector with length (v) elements"); |
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42 elseif (! (all (p >= 0) && any (p))) |
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43 error ("discrete_pdf: p must be a nonzero, nonnegative vector"); |
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44 endif |
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45 |
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46 n = numel (x); |
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47 m = length (v); |
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48 x = reshape (x, n, 1); |
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49 v = reshape (v, 1, m); |
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50 p = reshape (p / sum (p), m, 1); |
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51 |
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52 pdf = zeros (sz); |
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53 k = find (isnan (x)); |
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54 if (any (k)) |
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55 pdf (k) = NaN; |
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56 endif |
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57 k = find (!isnan (x)); |
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58 if (any (k)) |
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59 n = length (k); |
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60 pdf (k) = ((x(k) * ones (1, m)) == (ones (n, 1) * v)) * p; |
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61 endif |
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62 |
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63 endfunction |
