🐛 Add Warning for VahadaneExtractor Algorithm Instability

tiatoolbox/tools/stainextract.py

@@ -5,6 +5,7 @@
 import numpy as np
 from sklearn.decomposition import DictionaryLearning
 
+from tiatoolbox import logger
 from tiatoolbox.utils.misc import get_luminosity_tissue_mask
 from tiatoolbox.utils.transforms import rgb2od
 
@@ -238,6 +239,12 @@ class VahadaneExtractor:
     This class contains code inspired by StainTools
     [https://github.com/Peter554/StainTools] written by Peter Byfield.
 
+    .. warning::
+        Vahadane stain extraction/normalization algorithms are unstable
+        after the update to `dictionary learning` algorithm in
+        scikit-learn > v0.23.0 (see issue #382). Please be advised and
+        consider using other stain extraction (normalization) algorithms.
+
     Args:
         luminosity_threshold (float):
             Threshold used for tissue area selection.
@@ -259,6 +266,14 @@ def __init__(
         regularizer: float = 0.1,
     ) -> None:
         """Initialize :class:`VahadaneExtractor`."""
+        # Issue a warning about the algorithm's stability
+        logger.warning(
+            "Vahadane stain extraction/normalization algorithms are unstable "
+            "after the update to `dictionary learning` algorithm in "
+            "scikit-learn > v0.23.0 (see issue #382). Please be advised and "
+            "consider using other stain extraction (normalization) algorithms.",
+            stacklevel=2,
+        )
         self.__luminosity_threshold = luminosity_threshold
         self.__regularizer = regularizer
 
@@ -267,7 +282,7 @@ def get_stain_matrix(self: VahadaneExtractor, img: np.ndarray) -> np.ndarray:
 
         Args:
             img (:class:`numpy.ndarray`):
-                Input image used for stain matrix estimation
+                Input image used for stain matrix estimation.
 
         Returns:
             :class:`numpy.ndarray`: