update packages

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

diff --git a/octave_packages/m/statistics/distributions/geornd.m b/octave_packages/m/statistics/distributions/geornd.m
new file mode 100644 (file)
index 0000000..d2c7f25
--- /dev/null
+++ b/octave_packages/m/statistics/distributions/geornd.m
@@ -0,0 +1,125 @@
+## 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} {} geornd (@var{p})
+## @deftypefnx {Function File} {} geornd (@var{p}, @var{r})
+## @deftypefnx {Function File} {} geornd (@var{p}, @var{r}, @var{c}, @dots{})
+## @deftypefnx {Function File} {} geornd (@var{p}, [@var{sz}])
+## Return a matrix of random samples from the geometric distribution with
+## parameter @var{p}.
+##
+## When called with a single size argument, return a square matrix with
+## the dimension specified.  When called with more than one scalar argument the
+## first two arguments are taken as the number of rows and columns and any
+## further arguments specify additional matrix dimensions.  The size may also
+## be specified with a vector of dimensions @var{sz}.
+## 
+## If no size arguments are given then the result matrix is the size of
+## @var{p}.
+## @end deftypefn
+
+## Author: KH <Kurt.Hornik@wu-wien.ac.at>
+## Description: Random deviates from the geometric distribution
+
+function rnd = geornd (p, varargin)
+
+  if (nargin < 1)
+    print_usage ();
+  endif
+
+  if (nargin == 1)
+    sz = size (p);
+  elseif (nargin == 2)
+    if (isscalar (varargin{1}) && varargin{1} >= 0)
+      sz = [varargin{1}, varargin{1}];
+    elseif (isrow (varargin{1}) && all (varargin{1} >= 0))
+      sz = varargin{1};
+    else
+      error ("geornd: dimension vector must be row vector of non-negative integers");
+    endif
+  elseif (nargin > 2)
+    if (any (cellfun (@(x) (!isscalar (x) || x < 0), varargin)))
+      error ("geornd: dimensions must be non-negative integers");
+    endif
+    sz = [varargin{:}];
+  endif
+
+  if (!isscalar (p) && !isequal (size (p), sz))
+    error ("geornd: P must be scalar or of size SZ");
+  endif
+
+  if (iscomplex (p))
+    error ("geornd: P must not be complex");
+  endif
+
+  if (isa (p, "single"))
+    cls = "single";
+  else
+    cls = "double";
+  endif
+
+  if (isscalar (p))
+    if (p > 0 && p < 1);
+      rnd = floor (- rande (sz) ./ log (1 - p));
+    elseif (p == 0)
+      rnd = Inf (sz, cls);
+    elseif (p == 1)
+      rnd = zeros (sz, cls);
+    elseif (p < 0 || p > 1)
+      rnd = NaN (sz, cls);
+    endif
+  else
+    rnd = floor (- rande (sz) ./ log (1 - p));
+
+    k = !(p >= 0) | !(p <= 1);
+  rnd(k) = NaN;
+
+    k = (p == 0);
+    rnd(k) = Inf;
+  endif
+
+endfunction
+
+
+%!assert(size (geornd (0.5)), [1, 1]);
+%!assert(size (geornd (0.5*ones(2,1))), [2, 1]);
+%!assert(size (geornd (0.5*ones(2,2))), [2, 2]);
+%!assert(size (geornd (0.5, 3)), [3, 3]);
+%!assert(size (geornd (0.5, [4 1])), [4, 1]);
+%!assert(size (geornd (0.5, 4, 1)), [4, 1]);
+
+%% Test class of input preserved
+%!assert(class (geornd (0.5)), "double");
+%!assert(class (geornd (single(0.5))), "single");
+%!assert(class (geornd (single([0.5 0.5]))), "single");
+%!assert(class (geornd (single(0))), "single");
+%!assert(class (geornd (single(1))), "single");
+
+%% Test input validation
+%!error geornd ()
+%!error geornd (ones(3),ones(2))
+%!error geornd (ones(2),ones(3))
+%!error geornd (i)
+%!error geornd (1, -1)
+%!error geornd (1, ones(2))
+%!error geornd (1, [2 -1 2])
+%!error geornd (ones(2,2), 2, 3)
+%!error geornd (ones(2,2), 3, 2)
+