## Copyright (C) 2012 Rik Wehbring ## Copyright (C) 1995-2013 Kurt Hornik ## ## This file is part of Octave. ## ## Octave is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 3 of the License, or (at ## your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## . ## -*- texinfo -*- ## @deftypefn {Function File} {} binocdf (@var{x}, @var{n}, @var{p}) ## For each element of @var{x}, compute the cumulative distribution function ## (CDF) at @var{x} of the binomial distribution with parameters @var{n} and ## @var{p}, where @var{n} is the number of trials and @var{p} is the ## probability of success. ## @end deftypefn ## Author: KH ## Description: CDF of the binomial distribution function cdf = binocdf (x, n, p, upper) if (nargin != 3 && nargin != 4) print_usage (); endif if (nargin == 4) if (strcmp (upper, "upper")) upper = 1; else error ("binocdf: 4th parameter can only be \"upper\"\n"); endif else upper = 0; endif if (!isscalar (n) || !isscalar (p)) [retval, x, n, p] = common_size (x, n, p); if (retval > 0) error ("binocdf: X, N, and P must be of common size or scalars"); endif endif if (iscomplex (x) || iscomplex (n) || iscomplex (p)) error ("binocdf: X, N, and P must not be complex"); endif if (isa (x, "single") || isa (n, "single") || isa (p, "single")); cdf = zeros (size (x), "single"); else cdf = zeros (size (x)); endif k = isnan (x) | !(n >= 0) | (n != fix (n)) | !(p >= 0) | !(p <= 1); cdf(k) = NaN; k = (x >= n) & (n >= 0) & (n == fix (n) & (p >= 0) & (p <= 1)); cdf(k) = 1; k = (x >= 0) & (x < n) & (n == fix (n)) & (p >= 0) & (p <= 1); tmp = floor (x(k)); if (isscalar (n) && isscalar (p)); cdf(k) = betainc (1 - p, n - tmp, tmp + 1); if (upper == 1) cdf(k) = 1-cdf(k); endif else cdf(k) = betainc (1 .- p(k), n(k) - tmp, tmp + 1); if (upper == 1) cdf(k) = 1-cdf(k); endif endif endfunction %!shared x,y %! x = [-1 0 1 2 3]; %! y = [0 1/4 3/4 1 1]; %!assert (binocdf (x, 2*ones (1,5), 0.5*ones (1,5)), y) %!assert (binocdf (x, 2, 0.5*ones (1,5)), y) %!assert (binocdf (x, 2*ones (1,5), 0.5), y) %!assert (binocdf (x, 2*[0 -1 NaN 1.1 1], 0.5), [0 NaN NaN NaN 1]) %!assert (binocdf (x, 2, 0.5*[0 -1 NaN 3 1]), [0 NaN NaN NaN 1]) %!assert (binocdf ([x(1:2) NaN x(4:5)], 2, 0.5), [y(1:2) NaN y(4:5)]) %% Test class of input preserved %!assert (binocdf ([x, NaN], 2, 0.5), [y, NaN]) %!assert (binocdf (single ([x, NaN]), 2, 0.5), single ([y, NaN])) %!assert (binocdf ([x, NaN], single (2), 0.5), single ([y, NaN])) %!assert (binocdf ([x, NaN], 2, single (0.5)), single ([y, NaN])) %% Test input validation %!error binocdf () %!error binocdf (1) %!error binocdf (1,2) %!error binocdf (1,2,3,4) %!error binocdf (ones (3), ones (2), ones (2)) %!error binocdf (ones (2), ones (3), ones (2)) %!error binocdf (ones (2), ones (2), ones (3)) %!error binocdf (i, 2, 2) %!error binocdf (2, i, 2) %!error binocdf (2, 2, i)