I am analysing an article dealing with: "Semi-supervised Graph Clustering: A Kernel Approach" I need to reproduce figure 1 on page 7. http://www.cs.utexas.edu/users/inderjit/public_papers/kernel_icml.pdf

I didn't find the dataset of two circles? Could you please help me find that?

  • Do you need the exact same dataset, or just something similar?
    – tomp
    Jan 18, 2016 at 23:44
  • Just something similar. Jan 19, 2016 at 0:04

1 Answer 1


You could generate a similar dataset in Python using scikit-learn's make_circles function.

from sklearn.datasets import make_circles
import matplotlib.pyplot as plt

n_samples = 400

samples, labels = make_circles(n_samples=n_samples, factor=.3, noise=.05)

bluecircle = samples[labels==0]
redcircle  = samples[labels==1]

plt.scatter(bluecircle[:, 0], bluecircle[:, 1], c='b', marker='o', s=10)
plt.scatter(redcircle[:, 0], redcircle[:, 1], c='r', marker='+', s=30)

enter image description here

In Matlab you could could generate the dataset with something like:

n = 200;
step = 1/n;
radius = 0.5;
ratio = 0.4;


hold on;

% blue circle
idx = randsample(length([xp;yp]),n);
bluex = xp+(rand(length(xp),1)*radius/10)';
bluey = yp+(rand(length(yp),1)*radius/10)';

% red circle
idx = randsample(length([xp;yp]),n);
redx = ratio*xp+(rand(length(xp),1)*radius/10)';
redy = ratio*yp+(rand(length(yp),1)*radius/10)';

enter image description here

  • Thanks that helped me a lot, how could I generate the same graph with Matlab ? Jan 19, 2016 at 1:10
  • I've updated the answer with an example in Matlab
    – tomp
    Jan 20, 2016 at 2:37

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