Why Matlab2tikz can't show figures with categorial data? - matlab

Question

I plotted a bubble chart using scatter plot in Matlab with text lables on x axis and integer numbers on y axis. The bubble sizes are also considered as integer numbers. I included both code and figure of my chart. When I try to transform the figure to tikz using "matlab2tikz" library, I see the following error:
"Error using categorical/cat (line 69): Can not concatenate a double array and a categorical array".
I don't have any double numbers in my values. How can I transform this figure to tikz format?
x = ["C","A", "P", "K"]; %x lables
x1=categorical(x);
y = [33,68,200,14];% values
y1 = [48,177,200,16];
y2=[6,6,200,3];
sz = [35,7, 10, 56];%Bubble sizes
sz1=[25,7, 30, 53];
sz2=[44, 8,4,10];
scatter(x1,y,sz,'g','LineWidth',2);
hold on
scatter(x1,y1,sz1,'b','LineWidth',2);
hold on
scatter(x1,y2,sz2,'r','LineWidth',2);
hold off
legend({'y = Method1','y = Method2', 'y = Method3'},'Location','north');
title('NewModel');
ylabel('%Value');
saveas(gcf,'test.png');

Answer 1

You do have double numbers. y, y1 and y2 are double whereas x1 is categorical which is why you are getting that error.
For your case, the error can be fixed by changing the square brackets to curly brackets in line 4052. i.e. change:
data = [xData(:), yData(:)]; %line 4052 of matlab2tikz.m
to:
data = {xData(:), yData(:)};
The reason is what the error message says. You have categorical xData and double yData. These cannot be concatenated into a regular array. A cell array is for combining different types of data.
Similarly,
data=applyHgTransform(m2t,[xData(:), yData(:), zData(:)]); %line 4056 of matlab2tikz.m
should be modified to the following if you are plotting in 3D and have mixed data type:
data=applyHgTransform(m2t,{xData(:), yData(:), zData(:)});