multiple vectors histogram plotting

I would like to plot a histogram like the one in the picture, the x axis is labeled with different matrix names, and for each there is a bar showing the results of three solvers (each having a different colour). For some type of matrices (as matrix k in the picture), there could be no data for a certain solver. The y axis is set as log-scale. Following this stackoverflow, I wrote the following code, that is disastrous:

    x = [x1', x2', x3'];
    [y, b] = hist(x);
    hist(x);
    set(gca, 'YScale', 'log')

where x1, x2, x3 are the arrays of the results for each solver, where the missing data is set as 0.

Answer 1

[jean claude]

look at this example; it plots this matrix 24x3

load count.dat
hist(count)
legend('Intersection 1',...
'Intersection 2',...
'Intersection 3')