Mercurial > hg > octave-lyh
annotate scripts/statistics/distributions/gamrnd.m @ 10525:3306cfcb856e
Replace constructs like "NaN * one()" with "NaN()" and "Inf * ones ()" with "Inf()"
| author | David Bateman <dbateman@free.fr> |
|---|---|
| date | Fri, 16 Apr 2010 10:32:07 +0200 |
| parents | a1dbe9d80eee |
| children | 95c3e38098bf |
| 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} {} gamrnd (@var{a}, @var{b}, @var{r}, @var{c}) |
| 21 ## @deftypefnx {Function File} {} gamrnd (@var{a}, @var{b}, @var{sz}) | |
| 5410 | 22 ## Return an @var{r} by @var{c} or a @code{size (@var{sz})} matrix of |
| 23 ## random samples from the Gamma distribution with parameters @var{a} | |
| 24 ## and @var{b}. Both @var{a} and @var{b} 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{a} and @var{b}. | |
| 5642 | 29 ## @seealso{gamma, gammaln, gammainc, gampdf, gamcdf, gaminv} |
| 5410 | 30 ## @end deftypefn |
| 31 | |
| 5428 | 32 ## Author: KH <Kurt.Hornik@wu-wien.ac.at> |
| 5410 | 33 ## Description: Random deviates from the Gamma distribution |
| 34 | |
| 5411 | 35 function rnd = gamrnd (a, b, r, c) |
| 5410 | 36 |
| 37 if (nargin > 1) | |
| 38 if (!isscalar(a) || !isscalar(b)) | |
| 39 [retval, a, b] = common_size (a, b); | |
| 40 if (retval > 0) | |
| 5411 | 41 error ("gamrnd: a and b must be of common size or scalar"); |
| 5410 | 42 endif |
| 43 endif | |
| 44 endif | |
| 45 | |
| 46 if (nargin == 4) | |
| 47 if (! (isscalar (r) && (r > 0) && (r == round (r)))) | |
| 5411 | 48 error ("gamrnd: r must be a positive integer"); |
| 5410 | 49 endif |
| 50 if (! (isscalar (c) && (c > 0) && (c == round (c)))) | |
| 5411 | 51 error ("gamrnd: c must be a positive integer"); |
| 5410 | 52 endif |
| 53 sz = [r, c]; | |
| 54 | |
| 55 if (any (size (a) != 1) | |
| 56 && (length (size (a)) != length (sz) || any (size (a) != sz))) | |
| 5411 | 57 error ("gamrnd: a and b must be scalar or of size [r, c]"); |
| 5410 | 58 endif |
| 59 elseif (nargin == 3) | |
| 60 if (isscalar (r) && (r > 0)) | |
| 61 sz = [r, r]; | |
| 62 elseif (isvector(r) && all (r > 0)) | |
| 63 sz = r(:)'; | |
| 64 else | |
| 7007 | 65 error ("gamrnd: r must be a positive integer or vector"); |
| 5410 | 66 endif |
| 67 | |
| 68 if (any (size (a) != 1) | |
| 69 && (length (size (a)) != length (sz) || any (size (a) != sz))) | |
| 5411 | 70 error ("gamrnd: a and b must be scalar or of size sz"); |
| 5410 | 71 endif |
| 72 elseif (nargin == 2) | |
| 73 sz = size(a); | |
| 74 else | |
| 6046 | 75 print_usage (); |
| 5410 | 76 endif |
| 77 | |
| 78 rnd = zeros (sz); | |
| 79 | |
| 80 if (isscalar (a) && isscalar(b)) | |
| 81 if (find (!(a > 0) | !(a < Inf) | !(b > 0) | !(b < Inf))) | |
|
10525
3306cfcb856e
Replace constructs like "NaN * one()" with "NaN()" and "Inf * ones ()" with "Inf()"
David Bateman <dbateman@free.fr>
parents:
7017
diff
changeset
|
82 rnd = NaN (sz); |
| 5410 | 83 else |
| 6777 | 84 rnd = b .* randg(a, sz); |
| 5410 | 85 endif |
| 86 else | |
| 87 k = find (!(a > 0) | !(a < Inf) | !(b > 0) | !(b < Inf)); | |
| 88 if (any (k)) | |
| 89 rnd(k) = NaN; | |
| 90 endif | |
| 91 k = find ((a > 0) & (a < Inf) & (b > 0) & (b < Inf)); | |
| 92 if (any (k)) | |
| 6777 | 93 rnd(k) = b(k) .* randg(a(k), size(k)); |
| 5410 | 94 endif |
| 95 endif | |
| 96 | |
| 97 endfunction |