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diff --git a/octave_packages/m/specfun/pow2.m b/octave_packages/m/specfun/pow2.m
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+## 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  {Mapping Function} {} pow2 (@var{x})
+## @deftypefnx {Mapping Function} {} pow2 (@var{f}, @var{e})
+## With one argument, computes
+## @tex
+## $2^x$
+## @end tex
+## @ifnottex
+## 2 .^ x
+## @end ifnottex
+## for each element of @var{x}.
+##
+## With two arguments, returns
+## @tex
+## $f \cdot 2^e$.
+## @end tex
+## @ifnottex
+## f .* (2 .^ e).
+## @end ifnottex
+## @seealso{log2, nextpow2}
+## @end deftypefn
+
+## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at>
+## Created: 17 October 1994
+## Adapted-By: jwe
+
+function y = pow2 (f, e)
+
+  if (nargin == 1)
+    y = 2 .^ f;
+  elseif (nargin == 2)
+    y = f .* (2 .^ e);
+  else
+    print_usage ();
+  endif
+
+endfunction
+
+%!test
+%! x = [3, 0, -3];
+%! v = [8, 1, .125];
+%! assert(all (abs (pow2 (x) - v) < sqrt (eps)));
+
+%!test
+%! x = [3, 0, -3, 4, 0, -4, 5, 0, -5];
+%! y = [-2, -2, -2, 1, 1, 1, 3, 3, 3];
+%! z = x .* (2 .^ y);
+%! assert(all (abs (pow2 (x,y) - z) < sqrt (eps)));
+
+%!error pow2();
+