Merge pull request #3615 from VesnaT/fix_lin_proj

[FIX] LinearProjection: Disable LDA for less than three classes

Author: janezd

Orange/widgets/visualize/owlinearprojection.py

@@ -383,7 +383,7 @@ def _check_options(self):
 
         if self.data is not None:
             has_discrete_class = self.data.domain.has_discrete_class
-            if not has_discrete_class or len(np.unique(self.data.Y)) < 2:
+            if not has_discrete_class or len(np.unique(self.data.Y)) < 3:
                 buttons[self.Placement.LDA].setEnabled(False)
                 if self.placement == self.Placement.LDA:
                     self.placement = self.Placement.Circular

Orange/widgets/visualize/tests/test_owlinearprojection.py

@@ -183,6 +183,11 @@ def test_invalidated_model_selected(self):
         self.send_signal(self.widget.Inputs.data, self.data)
         self.widget.setup_plot.assert_called_once()
 
+    def test_two_classes_dataset(self):
+        self.widget.radio_placement.buttons[1].click()
+        self.send_signal(self.widget.Inputs.data, Table("heart_disease"))
+        self.assertFalse(self.widget.radio_placement.buttons[1].isEnabled())
+
 
 class LinProjVizRankTests(WidgetTest):
     """