update packages

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

diff --git a/octave_packages/m/statistics/distributions/unifinv.m b/octave_packages/m/statistics/distributions/unifinv.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} {} unifinv (@var{x})
+## @deftypefnx {Function File} {} unifinv (@var{x}, @var{a}, @var{b})
+## For each element of @var{x}, compute the quantile (the inverse of the
+## CDF) at @var{x} of the uniform distribution on the interval
+## [@var{a}, @var{b}].
+##
+## Default values are @var{a} = 0, @var{b} = 1.
+## @end deftypefn
+
+## Author: KH <Kurt.Hornik@wu-wien.ac.at>
+## Description: Quantile function of the uniform distribution
+
+function inv = unifinv (x, a = 0, b = 1)
+
+  if (nargin != 1 && nargin != 3)
+    print_usage ();
+  endif
+
+  if (!isscalar (a) || !isscalar (b))
+    [retval, x, a, b] = common_size (x, a, b);
+    if (retval > 0)
+      error ("unifinv: X, A, and B must be of common size or scalars");
+    endif
+  endif
+
+  if (iscomplex (x) || iscomplex (a) || iscomplex (b))
+    error ("unifinv: X, A, and B must not be complex");
+  endif
+
+  if (isa (x, "single") || isa (a, "single") || isa (b, "single"))
+    inv = NaN (size (x), "single");
+  else
+    inv = NaN (size (x));
+  endif
+
+  k = (x >= 0) & (x <= 1) & (a < b);
+  if (isscalar (a) && isscalar (b))
+    inv(k) = a + x(k) * (b - a);
+  else
+    inv(k) = a(k) + x(k) .* (b(k) - a(k));
+  endif
+
+endfunction
+
+
+%!shared x
+%! x = [-1 0 0.5 1 2];
+%!assert(unifinv (x, ones(1,5), 2*ones(1,5)), [NaN 1 1.5 2 NaN]);
+%!assert(unifinv (x, 1, 2*ones(1,5)), [NaN 1 1.5 2 NaN]);
+%!assert(unifinv (x, ones(1,5), 2), [NaN 1 1.5 2 NaN]);
+%!assert(unifinv (x, [1 2 NaN 1 1], 2), [NaN NaN NaN 2 NaN]);
+%!assert(unifinv (x, 1, 2*[1 0 NaN 1 1]), [NaN NaN NaN 2 NaN]);
+%!assert(unifinv ([x(1:2) NaN x(4:5)], 1, 2), [NaN 1 NaN 2 NaN]);
+
+%% Test class of input preserved
+%!assert(unifinv ([x, NaN], 1, 2), [NaN 1 1.5 2 NaN NaN]);
+%!assert(unifinv (single([x, NaN]), 1, 2), single([NaN 1 1.5 2 NaN NaN]));
+%!assert(unifinv ([x, NaN], single(1), 2), single([NaN 1 1.5 2 NaN NaN]));
+%!assert(unifinv ([x, NaN], 1, single(2)), single([NaN 1 1.5 2 NaN NaN]));
+
+%% Test input validation
+%!error unifinv ()
+%!error unifinv (1,2)
+%!error unifinv (1,2,3,4)
+%!error unifinv (ones(3),ones(2),ones(2))
+%!error unifinv (ones(2),ones(3),ones(2))
+%!error unifinv (ones(2),ones(2),ones(3))
+%!error unifinv (i, 2, 2)
+%!error unifinv (2, i, 2)
+%!error unifinv (2, 2, i)
+