diff --git a/load_data.py b/load_data.py
index 45efa853a08c35e80b95c9d850b8472d26204638..5f86b7c7ac2f500b103131d9d55ffe3ef2777344 100644
--- a/load_data.py
+++ b/load_data.py
@@ -367,10 +367,15 @@ def pretreat(
         df_filter = df[~pd.isna(df['impedance_nb'])]
     df = df_filter
 
-    # Derivate X values
+    # # Derivate X values
+    # if derivate:
+    #     df[X_labels] = df[X_labels].diff()
+    #     df = df.iloc[1:]
+
+    # Gradient X values
     if derivate:
-        df[X_labels] = df[X_labels].diff()
-        df = df.iloc[1:]
+        for x_label in X_labels:
+            df[x_label] = np.gradient(df[x_label].values)
 
     # Normalize X features
     if fit_scaler: