Improve infrastructure for experimental dispatching of non existing methods in cuML

python/cuml/cuml/internals/base.pyx

@@ -792,3 +792,25 @@ class UniversalBase(Base):
         """
 
         return False
+
+    def _check_cpu_model(self):
+        """
+        Checks if an estimator already has created a _cpu_model,
+        and creates one if necessary.
+        """
+        if not hasattr(self, "_cpu_model"):
+            self.import_cpu_model()
+            self.build_cpu_model()
+            self.gpu_to_cpu()
+
+    def __getattr__(self, attr):
+        try:
+            super().__getattr__(attr)
+
+        except AttributeError as ex:
+            if GlobalSettings().accelerator_active:
+                if hasattr(self._cpu_model_class, attr):
+                    self._check_cpu_model()
+                    return getattr(self._cpu_model, attr)
+
+            raise ex

python/cuml/cuml/tests/experimental/accel/estimators_hyperparams/test_accel_nearest_neighbors.py

@@ -96,7 +96,6 @@ def test_nearest_neighbors_n_jobs(synthetic_data, n_jobs):
     assert True, f"NearestNeighbors ran successfully with n_jobs={n_jobs}"
 
 
-@pytest.mark.xfail(reason="cuML doesn't have radius neighbors method")
 def test_nearest_neighbors_radius(synthetic_data):
     X, _ = synthetic_data
     radius = 1.0
@@ -143,7 +142,6 @@ def test_nearest_neighbors_kneighbors_graph(synthetic_data):
     ), f"Each sample should have {n_neighbors} neighbors in the graph"
 
 
-@pytest.mark.xfail(reason="cuML doesn't have radius neighbors graph method")
 def test_nearest_neighbors_radius_neighbors_graph(synthetic_data):
     X, _ = synthetic_data
     radius = 1.0