1 ## Copyright (C) 2012 Rik Wehbring
2 ## Copyright (C) 1995-2012 Kurt Hornik
4 ## This file is part of Octave.
6 ## Octave is free software; you can redistribute it and/or modify it
7 ## under the terms of the GNU General Public License as published by
8 ## the Free Software Foundation; either version 3 of the License, or (at
9 ## your option) any later version.
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12 ## WITHOUT ANY WARRANTY; without even the implied warranty of
13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 ## General Public License for more details.
16 ## You should have received a copy of the GNU General Public License
17 ## along with Octave; see the file COPYING. If not, see
18 ## <http://www.gnu.org/licenses/>.
21 ## @deftypefn {Function File} {} betacdf (@var{x}, @var{a}, @var{b})
22 ## For each element of @var{x}, compute the cumulative distribution function
23 ## (CDF) at @var{x} of the Beta distribution with parameters @var{a} and
27 ## Author: KH <Kurt.Hornik@wu-wien.ac.at>
28 ## Description: CDF of the Beta distribution
30 function cdf = betacdf (x, a, b)
36 if (!isscalar (a) || !isscalar (b))
37 [retval, x, a, b] = common_size (x, a, b);
39 error ("betacdf: X, A, and B must be of common size or scalars");
43 if (iscomplex (x) || iscomplex (a) || iscomplex (b))
44 error ("betacdf: X, A, and B must not be complex");
47 if (isa (x, "single") || isa (a, "single") || isa (b, "single"))
48 cdf = zeros (size (x), "single");
50 cdf = zeros (size (x));
53 k = isnan (x) | !(a > 0) | !(b > 0);
56 k = (x >= 1) & (a > 0) & (b > 0);
59 k = (x > 0) & (x < 1) & (a > 0) & (b > 0);
60 if (isscalar (a) && isscalar (b))
61 cdf(k) = betainc (x(k), a, b);
63 cdf(k) = betainc (x(k), a(k), b(k));
70 %! x = [-1 0 0.5 1 2];
71 %! y = [0 0 0.75 1 1];
72 %!assert(betacdf (x, ones(1,5), 2*ones(1,5)), y);
73 %!assert(betacdf (x, 1, 2*ones(1,5)), y);
74 %!assert(betacdf (x, ones(1,5), 2), y);
75 %!assert(betacdf (x, [0 1 NaN 1 1], 2), [NaN 0 NaN 1 1]);
76 %!assert(betacdf (x, 1, 2*[0 1 NaN 1 1]), [NaN 0 NaN 1 1]);
77 %!assert(betacdf ([x(1:2) NaN x(4:5)], 1, 2), [y(1:2) NaN y(4:5)]);
79 %% Test class of input preserved
80 %!assert(betacdf ([x, NaN], 1, 2), [y, NaN]);
81 %!assert(betacdf (single([x, NaN]), 1, 2), single([y, NaN]));
82 %!assert(betacdf ([x, NaN], single(1), 2), single([y, NaN]));
83 %!assert(betacdf ([x, NaN], 1, single(2)), single([y, NaN]));
85 %% Test input validation
89 %!error betacdf (1,2,3,4)
90 %!error betacdf (ones(3),ones(2),ones(2))
91 %!error betacdf (ones(2),ones(3),ones(2))
92 %!error betacdf (ones(2),ones(2),ones(3))