NEED HELP!!, How write a confusion matrix for 3 classes?

I WROTE a confusion matrix but the result out is only 2 classes not 3.

[Walter Roberson]

https://www.mathworks.com/help/deeplearning/ref/plotconfusion.html

Answer 1

[yanqi liu]

yes，sir，may be use categorical to get vector to confuse，such as

clc; clear all; close all;
%  for 3 classes
YTest = randi(3,[1 15]);
YPred = randi(3,[1 15]);
figure
c = confusionmat(categorical(YTest(:)), categorical(YPred(:)))

c = 3×3

4 2 3 0 0 1 1 3 1

t = confusionchart(categorical(YTest(:)), categorical(YPred(:)));