From 87df75786a139da908eca8ca63943b80f4b4f167 Mon Sep 17 00:00:00 2001
From: Awa Khouna <awa.khouna@polytechnique.edu>
Date: Tue, 26 Aug 2025 15:55:54 -0400
Subject: [PATCH] fix: adjust epsilon value for improved numerical stability in
 format_value method

---
 ocean/cp/_explanation.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/ocean/cp/_explanation.py b/ocean/cp/_explanation.py
index 4bb175d..6495d88 100644
--- a/ocean/cp/_explanation.py
+++ b/ocean/cp/_explanation.py
@@ -11,7 +11,7 @@
 
 
 class Explanation(Mapper[FeatureVar], BaseExplanation):
-    _epsilon: float = 1e-3
+    _epsilon: float = 1e-6
     _x: Array1D = np.zeros((0,), dtype=int)
 
     def vget(self, i: int) -> cp.IntVar:
@@ -73,6 +73,7 @@ def get(v: FeatureVar) -> Key | Number:
         return self.reduce(get)
 
     def format_value(self, f: int, idx: int, levels: list[float]) -> float:
+        eps = min(self._epsilon, 0.5 * min(np.diff(levels)))
         if self.query.shape[0] == 0:
             return float(levels[idx] + levels[idx + 1]) / 2
         j = 0
@@ -82,9 +83,9 @@ def format_value(self, f: int, idx: int, levels: list[float]) -> float:
         if j == idx:
             value = float(query_arr[f])
         elif j < idx:
-            value = float(levels[idx]) + self._epsilon
+            value = float(levels[idx]) + eps
         else:
-            value = float(levels[idx + 1]) - self._epsilon
+            value = float(levels[idx + 1]) - eps
         return value
 
     @property