## Copyright (C) 2008-2015 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} {} realpow (@var{x}, @var{y})
## Compute the real-valued, element-by-element power operator.
##
## This is equivalent to @w{@code{@var{x} .^ @var{y}}}, except that
## @code{realpow} reports an error if any return value is complex.
## @seealso{power, reallog, realsqrt}
## @end deftypefn

function z = realpow (x, y)

  if (nargin != 2)
    print_usage ();
  endif

  z = x .^ y;
  if (iscomplex (z))
    error ("realpow: produced complex result");
  endif

endfunction


%!assert (realpow (1:10, 0.5:0.5:5), power (1:10, 0.5:0.5:5))
%!assert (realpow (1:10, 0.5:0.5:5), [1:10] .^ [0.5:0.5:5])
%!test
%! x = rand (10, 10);
%! y = randn (10, 10);
%! assert (x.^y, realpow (x,y));
%!assert (realpow (1i,2), -1)

%!error realpow ()
%!error realpow (1)
%!error realpow (1,2,3)
%!error <produced complex result> realpow (-1, 1/2)