## Copyright (C) 2000-2012 Teemu Ikonen
##
## 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} {} loglogerr (@var{args})
## @deftypefnx {Function File} {@var{h} =} loglogerr (@var{args})
## Produce two-dimensional plots on a double logarithm axis with
## errorbars.
##
## Many different combinations of arguments are possible.  The most common
## form is
##
## @example
## loglogerr (@var{x}, @var{y}, @var{ey}, @var{fmt})
## @end example
##
## @noindent
## which produces a double logarithm plot of @var{y} versus @var{x}
## with errors in the @var{y}-scale defined by @var{ey} and the plot
## format defined by @var{fmt}.  See @code{errorbar} for available formats and
## additional information.
## @seealso{errorbar, semilogxerr, semilogyerr}
## @end deftypefn

## Created: 20.2.2001
## Author: Teemu Ikonen <tpikonen@pcu.helsinki.fi>
## Keywords: errorbar, plotting

function h = loglogerr (varargin)

  [hax, varargin] = __plt_get_axis_arg__ ("loglogerr", varargin{:});

  oldfig = ifelse (isempty (hax), [], get (0, "currentfigure"));
  unwind_protect
    hax = newplot (hax);

    set (hax, "xscale", "log", "yscale", "log");
    if (! ishold (hax))
      set (hax, "xminortick", "on", "yminortick", "on");
    endif
    htmp = __errcomm__ ("loglogerr", hax, varargin{:});

  unwind_protect_cleanup
    if (! isempty (oldfig))
      set (0, "currentfigure", oldfig);
    endif
  end_unwind_protect

  if (nargout > 0)
    h = htmp;
  endif

endfunction


%!demo
%! clf;
%! x = exp (log (0.01):0.2:log (10));
%! y = wblpdf (x, 3, 2);
%! eyu = 2*rand (size (y)) .* y;
%! eyl = 0.5*rand (size (y)) .* y;
%! loglogerr (x, y, eyl, eyu, '#~x-');
%! xlim (x([1, end]));