Add nan val check for barycenter features

src/fugw/mappings/sparse_barycenter.py

@@ -52,6 +52,10 @@ def update_barycenter_features(plans, weights_list, features_list, device):
                 else:
                     barycenter_features += acc
 
+        # Check for NaN values in the barycenter features
+        if torch.isnan(barycenter_features).any():
+            raise ValueError("Barycenter features contain NaN values")
+
         return barycenter_features.T
 
     @staticmethod