OWKmeans: Do not recluster when X does not change

Orange/widgets/unsupervised/owkmeans.py

@@ -469,8 +469,13 @@ def send_data(self):
     @Inputs.data
     @check_sql_input
     def set_data(self, data):
-        self.data = data
-        self.invalidate()
+        self.data, old_data = data, self.data
+
+        # Do not needlessly recluster the data if X hasn't changed
+        if old_data and self.data and np.array_equal(self.data.X, old_data.X):
+            self.send_data()
+        else:
+            self.invalidate()
 
     def send_report(self):
         # False positives (Setting is not recognized as int)

Orange/widgets/unsupervised/tests/test_owkmeans.py

@@ -8,7 +8,7 @@
 from AnyQt.QtWidgets import QRadioButton
 
 import Orange.clustering
-from Orange.data import Table
+from Orange.data import Table, Domain
 from Orange.widgets import gui
 from Orange.widgets.tests.base import WidgetTest
 from Orange.widgets.unsupervised.owkmeans import OWKMeans, ClusterTableModel
@@ -377,6 +377,43 @@ def test_invalidate_clusterings_cancels_jobs(self):
 
         self.assertEqual(widget.clusterings, {})
 
+    def test_do_not_recluster_on_same_data(self):
+        """Do not recluster data points when targets or metas change."""
+
+        # Prepare some dummy data
+        x = np.eye(5)
+        y1, y2 = np.ones((5, 1)), np.ones((5, 2))
+        meta1, meta2 = np.ones((5, 1)), np.ones((5, 2))
+
+        table1 = Table.from_numpy(
+            domain=Domain.from_numpy(X=x, Y=y1, metas=meta1),
+            X=x, Y=y1, metas=meta1,
+        )
+        # X is same, should not cause update
+        table2 = Table.from_numpy(
+            domain=Domain.from_numpy(X=x, Y=y2, metas=meta2),
+            X=x, Y=y2, metas=meta2,
+        )
+        # X is different, should cause update
+        table3 = table1.copy()
+        table3.X[:, 0] = 1
+
+        with patch.object(self.widget, 'commit') as commit:
+            self.send_signal(self.widget.Inputs.data, table1)
+            self.commit_and_wait()
+            call_count = commit.call_count
+            print(call_count)
+
+            # Sending data with same X should not recompute the clustering
+            self.send_signal(self.widget.Inputs.data, table2)
+            self.commit_and_wait()
+            self.assertEqual(call_count, commit.call_count)
+
+            # Sending data with different X should recompute the clustering
+            self.send_signal(self.widget.Inputs.data, table3)
+            self.commit_and_wait()
+            self.assertEqual(call_count + 1, commit.call_count)
+
 
 if __name__ == "__main__":
     unittest.main()