update packages

[CreaPhase.git] / octave_packages / m / statistics / distributions / hygepdf.m

diff --git a/octave_packages/m/statistics/distributions/hygepdf.m b/octave_packages/m/statistics/distributions/hygepdf.m
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+## Copyright (C) 2012 Rik Wehbring
+## Copyright (C) 1996-2012 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
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} hygepdf (@var{x}, @var{t}, @var{m}, @var{n})
+## Compute the probability density function (PDF) at @var{x} of the
+## hypergeometric distribution with parameters @var{t}, @var{m}, and
+## @var{n}.  This is the probability of obtaining @var{x} marked items
+## when randomly drawing a sample of size @var{n} without replacement
+## from a population of total size @var{t} containing @var{m} marked items.
+##
+## The parameters @var{t}, @var{m}, and @var{n} must be positive integers
+## with @var{m} and @var{n} not greater than @var{t}.
+## @end deftypefn
+
+## Author: KH <Kurt.Hornik@wu-wien.ac.at>
+## Description: PDF of the hypergeometric distribution
+
+function pdf = hygepdf (x, t, m, n)
+
+  if (nargin != 4)
+    print_usage ();
+  endif
+
+  if (!isscalar (t) || !isscalar (m) || !isscalar (n))
+    [retval, x, t, m, n] = common_size (x, t, m, n);
+    if (retval > 0)
+      error ("hygepdf: X, T, M, and N must be of common size or scalars");
+    endif
+  endif
+
+  if (iscomplex (x) || iscomplex (t) || iscomplex (m) || iscomplex (n))
+    error ("hygepdf: X, T, M, and N must not be complex");
+  endif
+
+  if (isa (x, "single") || isa (t, "single") || isa (m, "single") || isa (n, "single"))
+    pdf = zeros (size (x), "single");
+  else
+    pdf = zeros (size (x));
+  endif
+
+  ## everything in nel gives NaN
+  nel = (isnan (x) | (t < 0) | (m < 0) | (n <= 0) | (m > t) | (n > t) |
+        (t != fix (t)) | (m != fix (m)) | (n != fix (n)));
+  ## everything in zel gives 0 unless in nel
+  zel = ((x != fix (x)) | (x < 0) | (x > m) | (n < x) | (n-x > t-m));
+
+  pdf(nel) = NaN;
+
+  k = !nel & !zel;
+  if (any (k(:)))
+    if (isscalar (t) && isscalar (m) && isscalar (n))
+      pdf(k) = (bincoeff (m, x(k)) .* bincoeff (t-m, n-x(k))
+                / bincoeff (t, n));
+    else
+      pdf(k) = (bincoeff (m(k), x(k)) .* bincoeff (t(k)-m(k), n(k)-x(k))
+                ./ bincoeff (t(k), n(k)));
+    endif
+  endif
+
+endfunction
+
+
+%!shared x,y
+%! x = [-1 0 1 2 3];
+%! y = [0 1/6 4/6 1/6 0];
+%!assert(hygepdf (x, 4*ones(1,5), 2, 2), y);
+%!assert(hygepdf (x, 4, 2*ones(1,5), 2), y);
+%!assert(hygepdf (x, 4, 2, 2*ones(1,5)), y);
+%!assert(hygepdf (x, 4*[1 -1 NaN 1.1 1], 2, 2), [0 NaN NaN NaN 0]);
+%!assert(hygepdf (x, 4, 2*[1 -1 NaN 1.1 1], 2), [0 NaN NaN NaN 0]);
+%!assert(hygepdf (x, 4, 5, 2), [NaN NaN NaN NaN NaN]);
+%!assert(hygepdf (x, 4, 2, 2*[1 -1 NaN 1.1 1]), [0 NaN NaN NaN 0]);
+%!assert(hygepdf (x, 4, 2, 5), [NaN NaN NaN NaN NaN]);
+%!assert(hygepdf ([x, NaN], 4, 2, 2), [y, NaN], eps);
+
+%% Test class of input preserved
+%!assert(hygepdf (single([x, NaN]), 4, 2, 2), single([y, NaN]));
+%!assert(hygepdf ([x, NaN], single(4), 2, 2), single([y, NaN]));
+%!assert(hygepdf ([x, NaN], 4, single(2), 2), single([y, NaN]));
+%!assert(hygepdf ([x, NaN], 4, 2, single(2)), single([y, NaN]));
+
+%% Test input validation
+%!error hygepdf ()
+%!error hygepdf (1)
+%!error hygepdf (1,2)
+%!error hygepdf (1,2,3)
+%!error hygepdf (1,2,3,4,5)
+%!error hygepdf (1, ones(3),ones(2),ones(2))
+%!error hygepdf (1, ones(2),ones(3),ones(2))
+%!error hygepdf (1, ones(2),ones(2),ones(3))
+%!error hygepdf (i, 2, 2, 2)
+%!error hygepdf (2, i, 2, 2)
+%!error hygepdf (2, 2, i, 2)
+%!error hygepdf (2, 2, 2, i)
+