2 % TCDF returns student cumulative distribtion function
6 % Computes the CDF of the students distribution
7 % with DF degrees of freedom
8 % x,DF must be matrices of same size, or any one can be a scalar.
10 % see also: NORMCDF, TPDF, TINV
14 % $Id: tcdf.m 9033 2011-11-08 20:58:07Z schloegl $
15 % Copyright (C) 2000-2003,2009 by Alois Schloegl <alois.schloegl@gmail.com>
16 % This is part of the NaN-toolbox. For more details see
17 % http://pub.ist.ac.at/~schloegl/matlab/NaN/
19 % This program is free software; you can redistribute it and/or modify
20 % it under the terms of the GNU General Public License as published by
21 % the Free Software Foundation; either version 3 of the License, or
22 % (at your option) any later version.
24 % This program is distributed in the hope that it will be useful,
25 % but WITHOUT ANY WARRANTY; without even the implied warranty of
26 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27 % GNU General Public License for more details.
29 % You should have received a copy of the GNU General Public License
30 % along with this program; If not, see <http://www.gnu.org/licenses/>.
33 % check size of arguments
35 x = repmat(x,size(n));
36 elseif all(size(n)==1)
37 n = repmat(n,size(x));
38 elseif all(size(x)==size(n))
41 error('size of input arguments must be equal or scalar')
46 p((x==Inf) & (n>0)) = 1;
48 % workaround for invalid arguments in BETAINC
49 ix = isnan(x) | ~(n>0);
52 ix = (x > -Inf) & (x < Inf) & (n > 0);
53 p(ix) = betainc (n(ix) ./ (n(ix) + x(ix).^2), n(ix)/2, 1/2) / 2;
59 p = reshape(p,size(x));
61 %!assert(tcdf(NaN,4),NaN)