added warning back in and fixed issue with checking bottleneck import

treeple/stats/utils.py

@@ -1,5 +1,6 @@
+import importlib.util
 import os
-import sys
+import warnings
 from typing import Optional, Tuple
 
 import numpy as np
@@ -19,11 +20,14 @@
 from treeple._lib.sklearn.ensemble._forest import BaseForest, ForestClassifier
 
 BOTTLENECK_AVAILABLE = False
-if "bottleneck" in sys.modules:
+if importlib.util.find_spec("bottleneck"):
     import bottleneck as bn
 
     BOTTLENECK_AVAILABLE = True
 
+BOTTLENECK_WARNING = (
+    "Not using bottleneck for calculations involvings nans. Expect slower performance."
+)
 DISABLE_BN_ENV_VAR = "TREEPLE_NO_BOTTLENECK"
 
 if BOTTLENECK_AVAILABLE and DISABLE_BN_ENV_VAR not in os.environ:
@@ -257,6 +261,9 @@ def _compute_null_distribution_coleman(
     metric_star_pi : ArrayLike of shape (n_samples,)
         An array of the metrics computed on the other half of the trees.
     """
+    if not BOTTLENECK_AVAILABLE:
+        warnings.warn(BOTTLENECK_WARNING)
+
     # sample two sets of equal number of trees from the combined forest these are the posteriors
     # (n_estimators * 2, n_samples, n_outputs)
     all_y_pred = np.concatenate((y_pred_proba_normal, y_pred_proba_perm), axis=0)