Unable to recreate k-means clustering example

As per title, i'm unable to recreate the following example (k-means clustering - MATLAB kmeans - MathWorks Italia), the k means clustering of Fisher's iris dataset.

This is the code in question

load fisheriris
X = meas(:,3:4);
figure;
plot(X(:,1),X(:,2),'k*','MarkerSize',5);
title 'Fisher''s Iris Data';
xlabel 'Petal Lengths (cm)'; 
ylabel 'Petal Widths (cm)'
rng(1); % For reproducibility
[idx,C] = kmeans(X,3);
x1 = min(X(:,1)):0.01:max(X(:,1));
x2 = min(X(:,2)):0.01:max(X(:,2));
[x1G,x2G] = meshgrid(x1,x2);
XGrid = [x1G(:),x2G(:)]; % Defines a fine grid on the plot
idx2Region = kmeans(XGrid,3,'MaxIter',1,'Start',C);
figure;
gscatter(XGrid(:,1),XGrid(:,2),idx2Region,...
    [0,0.75,0.75;0.75,0,0.75;0.75,0.75,0],'..');
hold on;
plot(X(:,1),X(:,2),'k*','MarkerSize',5);
title 'Fisher''s Iris Data';
xlabel 'Petal Lengths (cm)';
ylabel 'Petal Widths (cm)'; 
legend('Region 1','Region 2','Region 3','Data','Location','SouthEast');
hold off;

An error occurs at line 16 involving the kmeans function

Error in Kmeans_dimostrativo (line 16)

[idx,C] = kmeans(X,3);

So i started digging in the kmeans function

function [label, mu, energy] = kmeans(X, m)
% Perform kmeans clustering.
% Input:
%   X: d x n data matrix
%   m: initialization parameter
% Output:
%   label: 1 x n sample labels
%   mu: d x k center of clusters
%   energy: optimization target value
% Written by Mo Chen ([e-mail]).
label = init(X, m);
n = numel(label);
idx = 1:n;
last = zeros(1,n);
while any(label ~= last)
    [~,~,last(:)] = unique(label);                  % remove empty clusters
    mu = X*normalize(sparse(idx,last,1),1);         % compute cluster centers 
    [val,label] = min(dot(mu,mu,1)'/2-mu'*X,[],1);  % assign sample labels
end
energy = dot(X(:),X(:),1)+2*sum(val);
function label = init(X, m)
[d,n] = size(X);
if numel(m) == 1                           % random initialization
    mu = X(:,randperm(n,m));
    [~,label] = min(dot(mu,mu,1)'/2-mu'*X,[],1); 
elseif all(size(m) == [1,n])               % init with labels
    label = m;
elseif size(m,1) == d                      % init with seeds (centers)
    [~,label] = min(dot(m,m,1)'/2-m'*X,[],1); 
end

The following error messages are the ones relative to the kmeans function

Error using randperm

K must be less than or equal to N.

Error in kmeans>init (line 25)

mu = X(:,randperm(n,m));

Error in kmeans (line 11)

label = init(X, m);

I honestly don't know the reason for the errors, i took the script directly from the website.

Answer 1

[Star Strider]

It works correctly in R2024a. (The online documentation reflects the latest update to the current release, and may not run correctly in earlier releases.)

There are apparently version differences in kmeans between R2023b and R2024a, although I don’t see any mention of updates or bug fixes regarding it in rhe Release Notes for R2024a, or bug fixes in R2023b.

Copy the relevant code from your R2023b documentation, be certain that you have installed all the lates updaates to R2023b, or upgrade to R2024a.

load fisheriris
X = meas(:,3:4);
figure;
plot(X(:,1),X(:,2),'k*','MarkerSize',5);
title 'Fisher''s Iris Data';
xlabel 'Petal Lengths (cm)'; 
ylabel 'Petal Widths (cm)'

rng(1); % For reproducibility
[idx,C] = kmeans(X,3);
x1 = min(X(:,1)):0.01:max(X(:,1));
x2 = min(X(:,2)):0.01:max(X(:,2));
[x1G,x2G] = meshgrid(x1,x2);
XGrid = [x1G(:),x2G(:)]; % Defines a fine grid on the plot
idx2Region = kmeans(XGrid,3,'MaxIter',1,'Start',C);

Warning: Failed to converge in 1 iterations.

figure;
gscatter(XGrid(:,1),XGrid(:,2),idx2Region,...
    [0,0.75,0.75;0.75,0,0.75;0.75,0.75,0],'..');
hold on;
plot(X(:,1),X(:,2),'k*','MarkerSize',5);
title 'Fisher''s Iris Data';
xlabel 'Petal Lengths (cm)';
ylabel 'Petal Widths (cm)'; 
legend('Region 1','Region 2','Region 3','Data','Location','SouthEast');
hold off;

EDIT — Added clarification.

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