Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / nan-2.5.5 / tcdf.m

diff --git a/octave_packages/nan-2.5.5/tcdf.m b/octave_packages/nan-2.5.5/tcdf.m
new file mode 100644 (file)
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+++ b/octave_packages/nan-2.5.5/tcdf.m
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+function p = tcdf(x,n)
+% TCDF returns student cumulative distribtion function
+%
+% cdf = tcdf(x,DF);
+%
+% Computes the CDF of the students distribution 
+%    with DF degrees of freedom 
+% x,DF must be matrices of same size, or any one can be a scalar. 
+%
+% see also: NORMCDF, TPDF, TINV 
+
+% Reference(s):
+
+%      $Id: tcdf.m 9033 2011-11-08 20:58:07Z schloegl $
+%      Copyright (C) 2000-2003,2009 by Alois Schloegl <alois.schloegl@gmail.com>       
+%      This is part of the NaN-toolbox. For more details see
+%       http://pub.ist.ac.at/~schloegl/matlab/NaN/
+
+%    This program 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.
+%
+%    This program 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 this program; If not, see <http://www.gnu.org/licenses/>.
+
+
+% check size of arguments
+if all(size(x)==1)
+       x = repmat(x,size(n));
+elseif all(size(n)==1)
+       n = repmat(n,size(x));
+elseif all(size(x)==size(n))
+       ;       %% OK, do nothing
+else
+       error('size of input arguments must be equal or scalar')
+end;   
+               
+% allocate memory
+p = zeros(size(x));
+p((x==Inf) & (n>0)) = 1;
+
+% workaround for invalid arguments in BETAINC
+ix   = isnan(x) | ~(n>0);
+p(ix)= NaN;
+
+ix    = (x > -Inf) & (x < Inf) & (n > 0);
+p(ix) = betainc (n(ix) ./ (n(ix) + x(ix).^2), n(ix)/2, 1/2) / 2;
+
+ix    = find(x>0);
+p(ix) = 1 - p(ix);
+
+% shape output
+p = reshape(p,size(x));
+
+%!assert(tcdf(NaN,4),NaN)