Change log(x+1) to log1p(x) in LogTransformer

CHANGELOG.rst

@@ -16,6 +16,13 @@ Subsections for each version can be one of the following;
 
 Each individual change should have a link to the pull request after the description of the change.
 
+1.2.2 (2024-02-15)
+------------------
+Changed
+^^^^^^^
+- Changed LogTransformer to use log1p(x) instead of log(x+1) `#178 <https://github.com/lvgig/tubular/pull/178>`_
+- Changed unit tests using log(x+1) to log1p(x) `#178 <https://github.com/lvgig/tubular/pull/178>`_
+
 1.2.0 (2024-02-06)
 ------------------
 Added

tests/numeric/test_LogTransformer.py

@@ -96,8 +96,8 @@ def expected_df_2():
         """Expected output of test_expected_output_2."""
         df = d.create_df_3()
 
-        df["a_new_col"] = np.log(df["a"] + 1)
-        df["b_new_col"] = np.log(df["b"] + 1)
+        df["a_new_col"] = np.log1p(df["a"])
+        df["b_new_col"] = np.log1p(df["b"])
 
         return df.drop(columns=["a", "b"])
 
@@ -114,8 +114,8 @@ def expected_df_4():
         """Expected output of test_expected_output_4."""
         df = d.create_df_3()
 
-        df["a_new_col"] = np.log(df["a"] + 1)
-        df["b_new_col"] = np.log(df["b"] + 1)
+        df["a_new_col"] = np.log1p(df["a"])
+        df["b_new_col"] = np.log1p(df["b"])
 
         return df
 

tubular/_version.py

@@ -1 +1 @@
-__version__ = "1.2.0"
+__version__ = "1.2.2"

tubular/numeric.py

@@ -122,10 +122,10 @@ def transform(self, X: pd.DataFrame) -> pd.DataFrame:
                 raise ValueError(msg)
 
             if self.base is None:
-                X[new_column_names] = np.log(X[self.columns] + 1)
+                X[new_column_names] = np.log1p(X[self.columns])
 
             else:
-                X[new_column_names] = np.log(X[self.columns] + 1) / np.log(self.base)
+                X[new_column_names] = np.log1p(X[self.columns]) / np.log(self.base)
 
         else:
             if (X[self.columns] <= 0).sum().sum() > 0: