update packages

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

diff --git a/octave_packages/m/statistics/distributions/unidinv.m b/octave_packages/m/statistics/distributions/unidinv.m
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+## Copyright (C) 2012 Rik Wehbring
+## Copyright (C) 2007-2012 David Bateman
+##
+## 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} {} unidinv (@var{x}, @var{n})
+## For each element of @var{x}, compute the quantile (the inverse of
+## the CDF) at @var{x} of the discrete uniform distribution which assumes
+## the integer values 1--@var{n} with equal probability.
+## @end deftypefn
+
+function inv = unidinv (x, n)
+
+  if (nargin != 2)
+    print_usage ();
+  endif
+
+  if (! isscalar (n))
+    [retval, x, n] = common_size (x, n);
+    if (retval > 0)
+      error ("unidcdf: X and N must be of common size or scalars");
+    endif
+  endif
+
+  if (iscomplex (x) || iscomplex (n))
+    error ("unidinv: X and N must not be complex");
+  endif
+
+  if (isa (x, "single") || isa (n, "single"))
+    inv = NaN (size (x), "single");
+  else
+    inv = NaN (size (x));
+  endif
+
+  ## For Matlab compatibility, unidinv(0) = NaN
+  k = (x > 0) & (x <= 1) & (n > 0 & n == fix (n));
+  if (isscalar (n))
+    inv(k) = floor (x(k) * n);
+  else
+    inv(k) = floor (x(k) .* n(k));
+  endif
+
+endfunction
+
+
+%!shared x
+%! x = [-1 0 0.5 1 2];
+%!assert(unidinv (x, 10*ones(1,5)), [NaN NaN 5 10 NaN], eps);
+%!assert(unidinv (x, 10), [NaN NaN 5 10 NaN], eps);
+%!assert(unidinv (x, 10*[0 1 NaN 1 1]), [NaN NaN NaN 10 NaN], eps);
+%!assert(unidinv ([x(1:2) NaN x(4:5)], 10), [NaN NaN NaN 10 NaN], eps);
+
+%% Test class of input preserved
+%!assert(unidinv ([x, NaN], 10), [NaN NaN 5 10 NaN NaN], eps);
+%!assert(unidinv (single([x, NaN]), 10), single([NaN NaN 5 10 NaN NaN]), eps);
+%!assert(unidinv ([x, NaN], single(10)), single([NaN NaN 5 10 NaN NaN]), eps);
+
+%% Test input validation
+%!error unidinv ()
+%!error unidinv (1)
+%!error unidinv (1,2,3)
+%!error unidinv (ones(3),ones(2))
+%!error unidinv (ones(2),ones(3))
+%!error unidinv (i, 2)
+%!error unidinv (2, i)
+