1 function U03_test_kmeans
   2 %U03_TEST_KMEANS           Test kmeans.
   3 %
   4 %usage
   5 %  U03_test_kmeans
   6 %
   7 %author
   8 %  saputra@cs.tu-berlin.de
   9 
  10 % filename of script to test
  11 filename = 'kmeans.m';
  12 
  13 % generate data set
  14 mu_1 = [-4; 0];
  15 mu_2 = [4; 0];
  16 mu_3 = [0; sqrt(48)];
  17 ns = 50;
  18 X = [(randn(2, ns) + repmat(mu_1, 1, ns)) (randn(2, ns) + repmat(mu_2, 1, ns)) (randn(2, ns) + repmat(mu_3, 1, ns))];
  19 correct_r = [ones(1, ns) 2*ones(1, ns) 3*ones(1, ns)];
  20 correct_same_cluster = (repmat(correct_r, 3*ns, 1) == repmat(correct_r', 1, 3*ns));
  21 
  22 % run test
  23 if exist(filename, 'file')
  24     fprintf(['Testing ' filename  '...\n']);
  25     [mu, r] = kmeans(X, 3);
  26     assert_equal(size(correct_r), size(r), 'Size of r does not match. Remember: r has to be a row vector!');
  27     same_cluster = (repmat(r, 3*ns, 1) == repmat(r', 1, 3*ns));
  28     num_correct_clusterings = sum(sum(triu(correct_same_cluster == same_cluster, 1)));
  29     fprintf('Pairwise correct cluster belongings: %.2f %%\n', 100*(num_correct_clusterings/11175));
  30     fprintf('Please run the test multiple times. You should nearly always get 100 %%\n');
  31 else
  32     fprintf([filename 'not found.\n']);
  33 end
  34 
  35 function [] = assert_equal(A, B, error, success)
  36 
  37 if max(max(abs(A - B))) > 1e-3
  38     fprintf(['Error: ' error '\n']);
  39     expected = A
  40     got = B
  41 else
  42     if nargin > 3
  43         fprintf(['OK: ' success '\n']);
  44     end
  45 end