Mercurial > hg > octave-nkf
annotate scripts/statistics/distributions/binornd.m @ 8086:83646120b54c
Handle zero values of n in binornd correctly
| author | Mark van Rossum <mvanross@inf.ed.ac.uk> |
|---|---|
| date | Mon, 08 Sep 2008 10:49:46 -0400 |
| parents | a1dbe9d80eee |
| children | eb63fbe60fab |
| rev | line source |
|---|---|
| 7017 | 1 ## Copyright (C) 1995, 1996, 1997, 2005, 2006, 2007 Kurt Hornik |
| 5410 | 2 ## |
| 3 ## This file is part of Octave. | |
| 4 ## | |
| 5 ## Octave is free software; you can redistribute it and/or modify it | |
| 6 ## under the terms of the GNU General Public License as published by | |
| 7016 | 7 ## the Free Software Foundation; either version 3 of the License, or (at |
| 8 ## your option) any later version. | |
| 5410 | 9 ## |
| 10 ## Octave is distributed in the hope that it will be useful, but | |
| 11 ## WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 ## General Public License for more details. | |
| 14 ## | |
| 15 ## You should have received a copy of the GNU General Public License | |
| 7016 | 16 ## along with Octave; see the file COPYING. If not, see |
| 17 ## <http://www.gnu.org/licenses/>. | |
| 5410 | 18 |
| 19 ## -*- texinfo -*- | |
| 5411 | 20 ## @deftypefn {Function File} {} binornd (@var{n}, @var{p}, @var{r}, @var{c}) |
| 21 ## @deftypefnx {Function File} {} binornd (@var{n}, @var{p}, @var{sz}) | |
| 5410 | 22 ## Return an @var{r} by @var{c} or a @code{size (@var{sz})} matrix of |
| 23 ## random samples from the binomial distribution with parameters @var{n} | |
| 24 ## and @var{p}. Both @var{n} and @var{p} must be scalar or of size | |
| 25 ## @var{r} by @var{c}. | |
| 26 ## | |
| 27 ## If @var{r} and @var{c} are omitted, the size of the result matrix is | |
| 28 ## the common size of @var{n} and @var{p}. | |
| 29 ## @end deftypefn | |
| 30 | |
| 5428 | 31 ## Author: KH <Kurt.Hornik@wu-wien.ac.at> |
| 5410 | 32 ## Description: Random deviates from the binomial distribution |
| 33 | |
| 5411 | 34 function rnd = binornd (n, p, r, c) |
| 5410 | 35 |
| 36 if (nargin > 1) | |
| 37 if (!isscalar(n) || !isscalar(p)) | |
| 38 [retval, n, p] = common_size (n, p); | |
| 39 if (retval > 0) | |
| 5411 | 40 error ("binornd: n and p must be of common size or scalar"); |
| 5410 | 41 endif |
| 42 endif | |
| 43 endif | |
| 44 | |
| 45 if (nargin == 4) | |
| 46 if (! (isscalar (r) && (r > 0) && (r == round (r)))) | |
| 5411 | 47 error ("binornd: r must be a positive integer"); |
| 5410 | 48 endif |
| 49 if (! (isscalar (c) && (c > 0) && (c == round (c)))) | |
| 5411 | 50 error ("binornd: c must be a positive integer"); |
| 5410 | 51 endif |
| 52 sz = [r, c]; | |
| 53 | |
| 54 if (any (size (n) != 1) | |
| 55 && (length (size (n)) != length (sz) || any (size (n) != sz))) | |
| 5411 | 56 error ("binornd: n and must be scalar or of size [r, c]"); |
| 5410 | 57 endif |
| 58 elseif (nargin == 3) | |
| 59 if (isscalar (r) && (r > 0)) | |
| 60 sz = [r, r]; | |
| 61 elseif (isvector(r) && all (r > 0)) | |
| 62 sz = r(:)'; | |
| 63 else | |
| 7007 | 64 error ("binornd: r must be a positive integer or vector"); |
| 5410 | 65 endif |
| 66 | |
| 67 if (any (size (n) != 1) | |
| 68 && (length (size (n)) != length (sz) || any (size (n) != sz))) | |
| 5411 | 69 error ("binornd: n and must be scalar or of size sz"); |
| 5410 | 70 endif |
| 71 elseif (nargin == 2) | |
| 72 sz = size(n); | |
| 73 else | |
| 6046 | 74 print_usage (); |
| 5410 | 75 endif |
| 76 | |
| 77 if (isscalar (n) && isscalar (p)) | |
|
8086
83646120b54c
Handle zero values of n in binornd correctly
Mark van Rossum <mvanross@inf.ed.ac.uk>
parents:
7017
diff
changeset
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78 if (find (!(n >= 0) | !(n < Inf) | !(n == round (n)) | |
| 5410 | 79 !(p >= 0) | !(p <= 1))) |
| 80 rnd = NaN * ones (sz); | |
|
8086
83646120b54c
Handle zero values of n in binornd correctly
Mark van Rossum <mvanross@inf.ed.ac.uk>
parents:
7017
diff
changeset
|
81 elseif (n == 0) |
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83646120b54c
Handle zero values of n in binornd correctly
Mark van Rossum <mvanross@inf.ed.ac.uk>
parents:
7017
diff
changeset
|
82 rnd = zeros (sz); |
| 5410 | 83 else |
| 84 nel = prod (sz); | |
| 85 tmp = rand (n, nel); | |
| 86 rnd = sum(tmp < ones (n, nel) * p, 1); | |
| 87 rnd = reshape(rnd, sz); | |
| 88 endif | |
| 89 else | |
| 90 rnd = zeros (sz); | |
| 91 | |
|
8086
83646120b54c
Handle zero values of n in binornd correctly
Mark van Rossum <mvanross@inf.ed.ac.uk>
parents:
7017
diff
changeset
|
92 k = find (!(n >= 0) | !(n < Inf) | !(n == round (n)) | |
| 5410 | 93 !(p >= 0) | !(p <= 1)); |
| 94 if (any (k)) | |
| 95 rnd(k) = NaN; | |
| 96 endif | |
| 97 | |
| 98 k = find ((n > 0) & (n < Inf) & (n == round (n)) & (p >= 0) & (p <= 1)); | |
| 99 if (any (k)) | |
| 100 N = max (n(k)); | |
| 101 L = length (k); | |
| 102 tmp = rand (N, L); | |
| 103 ind = (1 : N)' * ones (1, L); | |
| 104 rnd(k) = sum ((tmp < ones (N, 1) * p(k)(:)') & | |
| 105 (ind <= ones (N, 1) * n(k)(:)'),1); | |
| 106 endif | |
| 107 endif | |
| 108 | |
| 109 endfunction | |
|
8086
83646120b54c
Handle zero values of n in binornd correctly
Mark van Rossum <mvanross@inf.ed.ac.uk>
parents:
7017
diff
changeset
|
110 |
|
83646120b54c
Handle zero values of n in binornd correctly
Mark van Rossum <mvanross@inf.ed.ac.uk>
parents:
7017
diff
changeset
|
111 %!assert (binornd(0, 0, 1), 0) |
|
83646120b54c
Handle zero values of n in binornd correctly
Mark van Rossum <mvanross@inf.ed.ac.uk>
parents:
7017
diff
changeset
|
112 %!assert (binornd([0, 0], [0, 0], 1, 2), [0, 0]) |