FIX Fix ranking for scipy >= 1.10. (#24483)

cmarmo · Micky774 · ogrisel · web-flow · commit 0bf24792d69e · 2022-09-23T17:25:49.000+02:00
Co-authored-by: Meekail Zain &lt;34613774+Micky774@users.noreply.github.com&gt;
Co-authored-by: Olivier Grisel &lt;olivier.grisel@ensta.org&gt;
diff --git a/sklearn/model_selection/_search.py b/sklearn/model_selection/_search.py
@@ -965,11 +965,12 @@ def _store(key_name, array, weights=None, splits=False, rank=False):
             results["std_%s" % key_name] = array_stds
 
             if rank:
-                rank_result = rankdata(-array_means, method="min")
                 # when input is nan, scipy >= 1.10 rankdata returns nan. To
-                # keep previous behaviour nans are set to the
-                # maximum possible rank
-                rank_result[np.isnan(rank_result)] = len(rank_result)
+                # keep previous behaviour nans are set to be smaller than the
+                # minimum value in the array before ranking
+                min_array_means = min(array_means) - 1
+                array_means = np.nan_to_num(array_means, copy=True, nan=min_array_means)
+                rank_result = rankdata(-array_means, method="min")
                 rank_result = np.asarray(rank_result, dtype=np.int32)
                 results["rank_%s" % key_name] = rank_result
 
