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1 ## Copyright (C) 1995, 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 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} {} binornd (@var{n}, @var{p}, @var{r}, @var{c}) |
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21 ## @deftypefnx {Function File} {} binornd (@var{n}, @var{p}, @var{sz}) |
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22 ## Return an @var{r} by @var{c} or a @code{size (@var{sz})} matrix of |
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23 ## random samples from the binomial distribution with parameters @var{n} |
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24 ## and @var{p}. Both @var{n} and @var{p} must be scalar or of size |
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25 ## @var{r} by @var{c}. |
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26 ## |
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27 ## If @var{r} and @var{c} are omitted, the size of the result matrix is |
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28 ## the common size of @var{n} and @var{p}. |
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29 ## @end deftypefn |
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30 |
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31 ## Author: KH <Kurt.Hornik@wu-wien.ac.at> |
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32 ## Description: Random deviates from the binomial distribution |
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33 |
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34 function rnd = binornd (n, p, r, c) |
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35 |
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36 if (nargin > 1) |
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37 if (!isscalar(n) || !isscalar(p)) |
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38 [retval, n, p] = common_size (n, p); |
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39 if (retval > 0) |
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40 error ("binornd: n and p must be of common size or scalar"); |
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41 endif |
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42 endif |
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43 endif |
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44 |
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45 if (nargin == 4) |
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46 if (! (isscalar (r) && (r > 0) && (r == round (r)))) |
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47 error ("binornd: r must be a positive integer"); |
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48 endif |
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49 if (! (isscalar (c) && (c > 0) && (c == round (c)))) |
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50 error ("binornd: c must be a positive integer"); |
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51 endif |
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52 sz = [r, c]; |
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53 |
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54 if (any (size (n) != 1) |
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55 && (length (size (n)) != length (sz) || any (size (n) != sz))) |
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56 error ("binornd: n and must be scalar or of size [r, c]"); |
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57 endif |
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58 elseif (nargin == 3) |
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59 if (isscalar (r) && (r > 0)) |
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60 sz = [r, r]; |
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61 elseif (isvector(r) && all (r > 0)) |
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62 sz = r(:)'; |
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63 else |
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64 error ("binornd: r must be a positive integer or vector"); |
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65 endif |
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66 |
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67 if (any (size (n) != 1) |
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68 && (length (size (n)) != length (sz) || any (size (n) != sz))) |
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69 error ("binornd: n and must be scalar or of size sz"); |
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70 endif |
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71 elseif (nargin == 2) |
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72 sz = size(n); |
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73 else |
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74 print_usage (); |
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75 endif |
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76 |
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77 if (isscalar (n) && isscalar (p)) |
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78 if (find (!(n > 0) | !(n < Inf) | !(n == round (n)) | |
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79 !(p >= 0) | !(p <= 1))) |
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80 rnd = NaN * ones (sz); |
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81 else |
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82 nel = prod (sz); |
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83 tmp = rand (n, nel); |
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84 rnd = sum(tmp < ones (n, nel) * p, 1); |
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85 rnd = reshape(rnd, sz); |
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86 endif |
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87 else |
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88 rnd = zeros (sz); |
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89 |
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90 k = find (!(n > 0) | !(n < Inf) | !(n == round (n)) | |
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91 !(p >= 0) | !(p <= 1)); |
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92 if (any (k)) |
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93 rnd(k) = NaN; |
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94 endif |
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95 |
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96 k = find ((n > 0) & (n < Inf) & (n == round (n)) & (p >= 0) & (p <= 1)); |
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97 if (any (k)) |
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98 N = max (n(k)); |
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99 L = length (k); |
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100 tmp = rand (N, L); |
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101 ind = (1 : N)' * ones (1, L); |
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102 rnd(k) = sum ((tmp < ones (N, 1) * p(k)(:)') & |
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103 (ind <= ones (N, 1) * n(k)(:)'),1); |
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104 endif |
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105 endif |
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106 |
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107 endfunction |
