Can the BAR and BARH functions in MATLAB 7.0.1 (R14SP1) handle negative values when plotting a stacked graph?

I have the following matrix in MATLAB:

a = [1 2; 1 -1];

Plotting a bar graph of this data with either the BAR or BARH function as follows gives a counterintuitive result:

bar(a,'stack')

barh(a,'stack')

In the resulting plot, the negative value is drawn over the positive value, so on the plot it looks like there is only one value in the second row. I expect the negative values to be displayed on the negative side of the axis.

Answer 1

[MathWorks Support Team]

The ability to display negative data values on the negative side of the axis when creating a stacked bar graph using BAR or BARH functions is currently not available in MATLAB.

As a work around, consider the following code

function barExtended(varargin)

% Create a stacked bar graph of both negative and positive values.

%

% Syntax.

% barExtended(Y)

%   Create a new figure window and place the bar plot within it.

%

% barExtended(axes_handle,Y)

%   Place the bar plot with the axes pointed to be axes_handle.

% Parse input.

if nargin == 1

    Y = varargin{1};

else

    Y = varargin{2};

end

% Positive components.

fh(1) = figure;

hP    = bar(gca,Y.*(Y>0),'stacked');

ahP   = gca;

% Negative components.

fh(2) = figure;

hN    = bar(Y.*(Y<0),'stacked');

% Clean up.

if nargin == 1

    set([hP,hN],'parent',ahP);

    delete(fh(2));

else

    set([hP,hN],'parent',varargin{1});

    delete(fh);   

end

end

Following is an illustrative example:

barExtended(rand(5)-rand(5))

As another possible workaround you can also use the function BARX attached with this solution.

[Walter Roberson]

Nikolay Iskrev comments,

This solution doens't work if one wants to add a legend to the plot. It is very disappointing that we have to use crude hacks like this one to make a basic bar chart in matlab.