Merge pull request #158 from PrimozGodec/poly-regression-warning

[ENH] Polynomial regression - warn about huge values
biolab · Apr 4, 2023 · 2061612 · 2061612
2 parents 474dcf6 + 9da80d1
commit 2061612
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Showing 2 changed files with 25 additions and 4 deletions.
diff --git a/orangecontrib/educational/widgets/owpolynomialregression.py b/orangecontrib/educational/widgets/owpolynomialregression.py
@@ -192,9 +192,14 @@ class Outputs(OWBaseLearner.Outputs):
     want_main_area = True
     graph_name = 'plot'
 
+    class Warning(OWBaseLearner.Warning):
+        large_diffs = Msg(
+            "Polynomial feature values are very large. "
+            "This may cause numerical instabilities."
+        )
+
     class Error(OWBaseLearner.Error):
-        all_none = \
-            Msg("All rows have undefined data.")
+        all_none = Msg("All rows have undefined data.")
         no_cont_variables =\
             Msg("Regression requires at least two numeric variables.")
         same_dep_indepvar =\
@@ -418,6 +423,7 @@ def error_and_clear(error=None):
 
         self.Error.all_none.clear()
         self.Error.same_dep_indepvar.clear()
+        self.Warning.large_diffs.clear()
         if self.data is None:
             error_and_clear()
             return
@@ -443,11 +449,14 @@ def error_and_clear(error=None):
         poly_learner.name = self.learner_name
 
         data_table, preprocessed_table, poly_preprocessor, \
-        expanded_data, predictor = \
-            poly_learner.data_and_model(self.data)
+        expanded_data, predictor = poly_learner.data_and_model(self.data)
         if preprocessed_table is None:
             error_and_clear(self.Error.all_none)
             return
+        if expanded_data.X.max() - expanded_data.X.min() > 1e14:
+            # the threshold defined with experimenting, instability typically
+            # started to have effects for values >= 1e15
+            self.Warning.large_diffs()
 
         model = None
         if hasattr(predictor, "model"):

diff --git a/orangecontrib/educational/widgets/tests/test_owpolynomialregression.py b/orangecontrib/educational/widgets/tests/test_owpolynomialregression.py
@@ -346,6 +346,18 @@ def test_coefficients(self):
         # I haven't computed these values manually, I just copied them
         np.testing.assert_almost_equal(coef.X.T, [[ 3.1052632, -0.2631579]])
 
+    def test_large_polynomial_values(self):
+        x, y = (ContinuousVariable(n) for n in "xy")
+        data = Table.from_numpy(Domain([x], y), [[1], [30]], [3, 5])
+        self.send_signal(self.widget.Inputs.data, data)
+
+        self.widget.controls.polynomialexpansion.setValue(9)
+        self.assertFalse(self.widget.Warning.large_diffs.is_shown())
+        self.widget.controls.polynomialexpansion.setValue(10)
+        self.assertTrue(self.widget.Warning.large_diffs.is_shown())
+        self.widget.controls.polynomialexpansion.setValue(9)
+        self.assertFalse(self.widget.Warning.large_diffs.is_shown())
+
 
 class PolynomialFeaturesTest(unittest.TestCase):
     def test_1d(self):