update packages

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

diff --git a/octave_packages/m/statistics/distributions/geopdf.m b/octave_packages/m/statistics/distributions/geopdf.m
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+## Copyright (C) 2012 Rik Wehbring
+## Copyright (C) 1995-2012 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} {} geopdf (@var{x}, @var{p})
+## For each element of @var{x}, compute the probability density function
+## (PDF) at @var{x} of the geometric distribution with parameter @var{p}.
+## @end deftypefn
+
+## Author: KH <Kurt.Hornik@wu-wien.ac.at>
+## Description: PDF of the geometric distribution
+
+function pdf = geopdf (x, p)
+
+  if (nargin != 2)
+    print_usage ();
+  endif
+
+  if (!isscalar (p))
+    [retval, x, p] = common_size (x, p);
+    if (retval > 0)
+      error ("geopdf: X and P must be of common size or scalars");
+    endif
+  endif
+
+  if (iscomplex (x) || iscomplex (p))
+    error ("geopdf: X and P must not be complex");
+  endif
+
+  if (isa (x, "single") || isa (p, "single"))
+    pdf = zeros (size (x), "single");
+  else
+    pdf = zeros (size (x));
+  endif
+
+  k = isnan (x) | (x == Inf) | !(p >= 0) | !(p <= 1);
+  pdf(k) = NaN;
+
+  k = (x >= 0) & (x < Inf) & (x == fix (x)) & (p > 0) & (p <= 1);
+  if (isscalar (p))
+    pdf(k) = p * ((1 - p) .^ x(k));
+  else
+    pdf(k) = p(k) .* ((1 - p(k)) .^ x(k));
+  endif
+
+endfunction
+
+
+%!shared x,y
+%! x = [-1 0 1 Inf];
+%! y = [0, 1/2, 1/4, NaN];
+%!assert(geopdf (x, 0.5*ones(1,4)), y);
+%!assert(geopdf (x, 0.5), y);
+%!assert(geopdf (x, 0.5*[-1 NaN 4 1]), [NaN NaN NaN y(4)]);
+%!assert(geopdf ([x, NaN], 0.5), [y, NaN]);
+
+%% Test class of input preserved
+%!assert(geopdf (single([x, NaN]), 0.5), single([y, NaN]), 5*eps("single"));
+%!assert(geopdf ([x, NaN], single(0.5)), single([y, NaN]), 5*eps("single"));
+
+%% Test input validation
+%!error geopdf ()
+%!error geopdf (1)
+%!error geopdf (1,2,3)
+%!error geopdf (ones(3),ones(2))
+%!error geopdf (ones(2),ones(3))
+%!error geopdf (i, 2)
+%!error geopdf (2, i)
+