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## -*- texinfo -*-
## @deftypefn  {} {} errorbar (@var{y}, @var{ey})
## @deftypefnx {} {} errorbar (@var{y}, @dots{}, @var{fmt})
## @deftypefnx {} {} errorbar (@var{x}, @var{y}, @var{ey})
## @deftypefnx {} {} errorbar (@var{x}, @var{y}, @var{err}, @var{fmt})
## @deftypefnx {} {} errorbar (@var{x}, @var{y}, @var{lerr}, @var{uerr}, @var{fmt})
## @deftypefnx {} {} errorbar (@var{x}, @var{y}, @var{ex}, @var{ey}, @var{fmt})
## @deftypefnx {} {} errorbar (@var{x}, @var{y}, @var{lx}, @var{ux}, @var{ly}, @var{uy}, @var{fmt})
## @deftypefnx {} {} errorbar (@var{x1}, @var{y1}, @dots{}, @var{fmt}, @var{xn}, @var{yn}, @dots{})
## @deftypefnx {} {} errorbar (@var{hax}, @dots{})
## @deftypefnx {} {@var{h} =} errorbar (@dots{})
## Create a 2-D plot with errorbars.
##
## Many different combinations of arguments are possible.  The simplest form is
##
## @example
## errorbar (@var{y}, @var{ey})
## @end example
##
## @noindent
## where the first argument is taken as the set of @var{y} coordinates, the
## second argument @var{ey} are the errors around the @var{y} values, and the
## @var{x} coordinates are taken to be the indices of the elements
## (@code{1:numel (@var{y})}).
##
## The general form of the function is
##
## @example
## errorbar (@var{x}, @var{y}, @var{err1}, @dots{}, @var{fmt}, @dots{})
## @end example
##
## @noindent
## After the @var{x} and @var{y} arguments there can be 1, 2, or 4
## parameters specifying the error values depending on the nature of the error
## values and the plot format @var{fmt}.
##
## @table @asis
## @item @var{err} (scalar)
## When the error is a scalar all points share the same error value.
## The errorbars are symmetric and are drawn from @var{data}-@var{err} to
## @var{data}+@var{err}.
## The @var{fmt} argument determines whether @var{err} is in the x-direction,
## y-direction (default), or both.
##
## @item @var{err} (vector or matrix)
## Each data point has a particular error value.
## The errorbars are symmetric and are drawn from @var{data}(n)-@var{err}(n) to
## @var{data}(n)+@var{err}(n).
##
## @item @var{lerr}, @var{uerr} (scalar)
## The errors have a single low-side value and a single upper-side value.
## The errorbars are not symmetric and are drawn from @var{data}-@var{lerr} to
## @var{data}+@var{uerr}.
##
## @item @var{lerr}, @var{uerr} (vector or matrix)
## Each data point has a low-side error and an upper-side error.
## The errorbars are not symmetric and are drawn from
## @var{data}(n)-@var{lerr}(n) to @var{data}(n)+@var{uerr}(n).
## @end table
##
## Any number of data sets (@var{x1},@var{y1}, @var{x2},@var{y2}, @dots{}) may
## appear as long as they are separated by a format string @var{fmt}.
##
## If @var{y} is a matrix, @var{x} and the error parameters must also be
## matrices having the same dimensions.  The columns of @var{y} are plotted
## versus the corresponding columns of @var{x} and errorbars are taken from
## the corresponding columns of the error parameters.
##
## If @var{fmt} is missing, the yerrorbars ("~") plot style is assumed.
##
## If the @var{fmt} argument is supplied then it is interpreted, as in normal
## plots, to specify the line style, marker, and color.  In addition,
## @var{fmt} may include an errorbar style which @strong{must precede} the
## ordinary format codes.  The following errorbar styles are supported:
##
## @table @samp
## @item ~
## Set yerrorbars plot style (default).
##
## @item >
## Set xerrorbars plot style.
##
## @item ~>
## Set xyerrorbars plot style.
##
## @item #~
## Set yboxes plot style.
##
## @item #
## Set xboxes plot style.
##
## @item #~>
## Set xyboxes plot style.
## @end table
##
## If the first argument @var{hax} is an axes handle, then plot into this axes,
## rather than the current axes returned by @code{gca}.
##
## The optional return value @var{h} is a handle to the hggroup object
## representing the data plot and errorbars.
##
## Note: For compatibility with @sc{matlab} a line is drawn through all data
## points.  However, most scientific errorbar plots are a scatter plot of
## points with errorbars.  To accomplish this, add a marker style to the
## @var{fmt} argument such as @qcode{"."}.  Alternatively, remove the line
## by modifying the returned graphic handle with
## @code{set (h, "linestyle", "none")}.
##
## Examples:
##
## @example
## errorbar (@var{x}, @var{y}, @var{ex}, ">.r")
## @end example
##
## @noindent
## produces an xerrorbar plot of @var{y} versus @var{x} with @var{x}
## errorbars drawn from @var{x}-@var{ex} to @var{x}+@var{ex}.  The marker
## @qcode{"."} is used so no connecting line is drawn and the errorbars
## appear in red.
##
## @example
## @group
## errorbar (@var{x}, @var{y1}, @var{ey}, "~",
##           @var{x}, @var{y2}, @var{ly}, @var{uy})
## @end group
## @end example
##
## @noindent
## produces yerrorbar plots with @var{y1} and @var{y2} versus @var{x}.
## Errorbars for @var{y1} are drawn from @var{y1}-@var{ey} to
## @var{y1}+@var{ey}, errorbars for @var{y2} from @var{y2}-@var{ly} to
## @var{y2}+@var{uy}.
##
## @example
## @group
## errorbar (@var{x}, @var{y}, @var{lx}, @var{ux},
##           @var{ly}, @var{uy}, "~>")
## @end group
## @end example
##
## @noindent
## produces an xyerrorbar plot of @var{y} versus @var{x} in which
## @var{x} errorbars are drawn from @var{x}-@var{lx} to @var{x}+@var{ux}
## and @var{y} errorbars from @var{y}-@var{ly} to @var{y}+@var{uy}.
## @seealso{semilogxerr, semilogyerr, loglogerr, plot}
## @end deftypefn

function h = errorbar (varargin)

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

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

    htmp = __errplot__ ("errorbar", hax, varargin{:});

    if (! ishold ())
      set (hax, "box", "on");
    endif
  unwind_protect_cleanup
    if (! isempty (oldfig))
      set (0, "currentfigure", oldfig);
    endif
  end_unwind_protect

  if (nargout > 0)
    h = htmp;
  endif

endfunction


%!demo
%! clf;
%! rand_1x11_data1 = [0.82712, 0.50325, 0.35613, 0.77089, 0.20474, 0.69160, 0.30858, 0.88225, 0.35187, 0.14168, 0.54270];
%! rand_1x11_data2 = [0.506375, 0.330106, 0.017982, 0.859270, 0.140641, 0.327839, 0.275886, 0.162453, 0.807592, 0.318509, 0.921112];
%! errorbar (0:10, rand_1x11_data1, 0.25*rand_1x11_data2);
%! title ("errorbar() with Y errorbars");

%!demo
%! clf;
%! rand_1x11_data3 = [0.423650, 0.142331, 0.213195, 0.129301, 0.975891, 0.012872, 0.635327, 0.338829, 0.764997, 0.401798, 0.551850];
%! rand_1x11_data4 = [0.682566, 0.456342, 0.132390, 0.341292, 0.108633, 0.601553, 0.040455, 0.146665, 0.309187, 0.586291, 0.540149];
%! errorbar (0:10, rand_1x11_data3, rand_1x11_data4, ">");
%! title ("errorbar() with X errorbars");

%!demo
%! clf;
%! x = 0:0.5:2*pi;
%! err = x/30;
%! y1 = sin (x);
%! y2 = cos (x);
%! errorbar (x, y1, err, "~", x, y2, err, ">");
%! legend ("Y errbar", "X errbar");
%! title ("errorbar() with 2 datasets");

%!demo
%! clf;
%! x = 0:0.5:2*pi;
%! err = x/30;
%! y1 = sin (x);
%! y2 = cos (x);
%! errorbar (x, y1, err, err, "#r", x, y2, err, err, "#~");
%! legend ("X errbox", "Y errbox");
%! title ("errorbar() with error boxes");

%!demo
%! clf;
%! x = 0:0.5:2*pi;
%! err = x/30;
%! y1 = sin (x);
%! y2 = cos (x);
%! errorbar (x, y1, err, err, err, err, "~>", ...
%!           x, y2, err, err, err, err, "#~>-*");
%! legend ("X-Y errbars", "X-Y errboxes");
%! title ("errorbar() with X-Y errorbars and error boxes");

## Invisible figure used for tests
%!shared hf, hax
%! hf = figure ("visible", "off");
%! hax = axes ();

%!error errorbar ()
%!error errorbar (1)
%!error <data argument 1 must be numeric> errorbar (hax, {1}, 2)
%!error <data argument 2 must be numeric> errorbar (hax, 1, {2})
%!error <size of argument 2 does not match others> errorbar (hax, 1, 1:2)
%!error <size of argument 3 does not match others> errorbar (hax, 1, 2, 3:4)
%!error <too many arguments to plot> errorbar (1,2,3,4,5,6,7)

%!error <2 column errorplot is only valid for xerr> errorbar (1,2, "~>")
%!error <6 columns only valid for xyerr and boxxy> errorbar (1,2,3,4,5,6, "~")
%!error <error plot requires 2, 3, 4, or 6 arguments> errorbar (1,2,3,4,5)

## Close figure used for testing
%!test
%! close (hf);