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1 ## Copyright (C) 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 3 of the License, or (at |
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8 ## your option) 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, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Function File} {} hygernd (@var{t}, @var{m}, @var{n}, @var{r}, @var{c}) |
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21 ## @deftypefnx {Function File} {} hygernd (@var{t}, @var{m}, @var{n}, @var{sz}) |
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22 ## @deftypefnx {Function File} {} hygernd (@var{t}, @var{m}, @var{n}) |
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23 ## Return an @var{r} by @var{c} matrix of random samples from the |
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24 ## hypergeometric distribution with parameters @var{t}, @var{m}, |
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25 ## and @var{n}. |
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26 ## |
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27 ## The parameters @var{t}, @var{m}, and @var{n} must positive integers |
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28 ## with @var{m} and @var{n} not greater than @var{t}. |
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29 ## |
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30 ## The parameter @var{sz} must be scalar or a vector of matrix |
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31 ## dimensions. If @var{sz} is scalar, then a @var{sz} by @var{sz} |
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32 ## matrix of random samples is generated. |
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33 ## @end deftypefn |
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34 |
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35 function rnd = hygernd (t, m, n, r, c) |
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36 |
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37 if (nargin == 5) |
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38 if (! (isscalar (r) && (r > 0) && (r == round (r)))) |
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39 error ("hygernd: r must be a positive integer"); |
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40 endif |
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41 if (! (isscalar (c) && (c > 0) && (c == round (c)))) |
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42 error ("hygernd: c must be a positive integer"); |
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43 endif |
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44 sz = [r, c]; |
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45 elseif (nargin == 4) |
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46 if (isvector (r) && all (r > 0) && all (r == round (r))) |
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47 if (isscalar (r)) |
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48 sz = [r, r]; |
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49 else |
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50 sz = r(:)'; |
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51 endif |
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52 else |
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53 error ("hygernd: r must be a vector of positive integers"); |
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54 endif |
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55 elseif (nargin != 3) |
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56 print_usage (); |
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57 endif |
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58 |
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59 if (! isscalar (t) || ! isscalar (m) || ! isscalar (n)) |
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60 [retval, t, m, n] = common_size (t, m, n); |
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61 if (retval > 0) |
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62 error ("hygernd: t, m and n must be of common size or scalar"); |
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63 endif |
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64 if (nargin > 3) |
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65 if (any (sz != size (t))) |
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66 error ("hygernd: t, m and n must have the same size as implied by r and c or must be scalar"); |
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67 endif |
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68 else |
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69 sz = size (t); |
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70 endif |
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71 elseif (nargin == 3) |
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72 sz = 1; |
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73 endif |
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74 |
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75 ## NaN elements |
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76 ne = (! (t >= 0) | ! (m >= 0) | ! (n > 0) | ! (t == round (t)) | ! (m == round (m)) | ! (n == round (n)) | ! (m <= t) | ! (n <= t)); |
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77 |
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78 if (! isscalar (t)) |
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79 rnd = zeros (sz); |
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80 rnd(ne) = NaN; |
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81 rn = rand (sz); |
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82 for i = find (! ne) |
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83 v = 0 : n(i); |
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84 p = hygepdf (v, t(i), m(i), n(i)); |
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85 rnd(i) = v(lookup (cumsum (p(1 : end-1)) / sum (p), rn(i)) + 1); |
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86 endfor |
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87 else |
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88 if (ne) |
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89 rnd = NaN * ones (sz); |
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90 else |
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91 v = 0:n; |
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92 p = hygepdf (v, t, m, n); |
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93 rnd = v(lookup (cumsum (p(1:end-1)) / sum (p), rand (sz)) + 1); |
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94 endif |
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95 endif |
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96 |
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97 endfunction |
