DOC Ensure chi2_kernel passes numpydoc validation (#23945)

Mathews-Tom · jeremiedbb · web-flow · commit 6d4c65397b2e · 2022-07-19T16:31:59.000+02:00
Co-authored-by: Jérémie du Boisberranger &lt;34657725+jeremiedbb@users.noreply.github.com&gt;
diff --git a/sklearn/metrics/pairwise.py b/sklearn/metrics/pairwise.py
@@ -1440,7 +1440,7 @@ def additive_chi2_kernel(X, Y=None):
 
 
 def chi2_kernel(X, Y=None, gamma=1.0):
-    """Computes the exponential chi-squared kernel X and Y.
+    """Compute the exponential chi-squared kernel between X and Y.
 
     The chi-squared kernel is computed between each pair of rows in X and Y.  X
     and Y have to be non-negative. This kernel is most commonly applied to
@@ -1457,15 +1457,18 @@ def chi2_kernel(X, Y=None, gamma=1.0):
     Parameters
     ----------
     X : array-like of shape (n_samples_X, n_features)
+        A feature array.
 
     Y : ndarray of shape (n_samples_Y, n_features), default=None
+        An optional second feature array. If `None`, uses `Y=X`.
 
-    gamma : float, default=1.
+    gamma : float, default=1
         Scaling parameter of the chi2 kernel.
 
     Returns
     -------
     kernel_matrix : ndarray of shape (n_samples_X, n_samples_Y)
+        The kernel matrix.
 
     See Also
     --------
diff --git a/sklearn/tests/test_docstrings.py b/sklearn/tests/test_docstrings.py
@@ -48,7 +48,6 @@
     "sklearn.metrics.cluster._supervised.rand_score",
     "sklearn.metrics.cluster._supervised.v_measure_score",
     "sklearn.metrics.pairwise.additive_chi2_kernel",
-    "sklearn.metrics.pairwise.chi2_kernel",
     "sklearn.metrics.pairwise.distance_metrics",
     "sklearn.metrics.pairwise.kernel_metrics",
     "sklearn.metrics.pairwise.pairwise_distances_argmin_min",
