@@ -288,7 +288,17 @@ class Learner1D(BaseLearner):

             # Calculate how many points belong to each interval.

             x_scale = self._scale[0]

-            quals = [(-loss if not math.isinf(loss) else (x0 - x1) / x_scale, (x0, x1), 1)

+

+            def _calc_quality(x0, x1, loss):

+                dx = x0 - x1

+                if abs(dx) < self._dx_eps:

+                    return 0

+                elif not math.isinf(loss):

+                    return -loss

+                else:

+                    return dx / x_scale

+

+            quals = [(_calc_quality(x0, x1, loss), (x0, x1), 1)

                      for ((x0, x1), loss) in self.losses_combined.items()]

             heapq.heapify(quals)