diff --git a/src/bayesvalidrox/post_processing/post_processing.py b/src/bayesvalidrox/post_processing/post_processing.py
index 1f4a8ff3c0cdb2b8eaebd0df3fda88a717e5f4ce..1280ad95994013c01302e57727013845524f7c73 100644
--- a/src/bayesvalidrox/post_processing/post_processing.py
+++ b/src/bayesvalidrox/post_processing/post_processing.py
@@ -227,7 +227,10 @@ class PostProcessing:
         if model_out_dict is not None:
             self.model_out_dict = model_out_dict
         else:
-            self.model_out_dict = self._eval_model(samples, key_str="valid")
+            self.model_out_dict, _ = self.engine.Model.run_model_parallel(
+                samples, key_str="valid"
+            )
+
         out_mean, out_std = self.engine.eval_metamodel(samples)
 
         self._plot_validation_multi(out_mean=out_mean, out_std=out_std)
@@ -980,7 +983,6 @@ class PostProcessing:
                     bbox_inches="tight",
                 )
                 plt.close(fig)
-
     # -------------------------------------------------------------------------
     def _plot_validation_multi(self, out_mean, out_std):
         """
@@ -1068,7 +1070,7 @@ class PostProcessing:
             r_2 = r2_score(y_val[idx].reshape(-1, 1), y_val[idx].reshape(-1, 1))
 
             plt.annotate(
-                f"RMSE = {rmse:.3f}\n $R^2$ = {r_2:.3f}",
+                f"RMSE = {rmse}\n $R^2$ = {r_2:.3f}",
                 xy=(0.85, 0.1),
                 xycoords="axes fraction",
             )
diff --git a/src/bayesvalidrox/surrogate_models/supplementary.py b/src/bayesvalidrox/surrogate_models/supplementary.py
index bd2aa6ce6d2a175dc45bb8dd211f0215a9a35204..05e825d40a48b2377558464452fda54771ab9be1 100644
--- a/src/bayesvalidrox/surrogate_models/supplementary.py
+++ b/src/bayesvalidrox/surrogate_models/supplementary.py
@@ -332,5 +332,7 @@ def root_mean_squared_error(reference, approximation):
         RMSE of approximation against the reference along the samples.
     """
     rmse = np.sqrt(np.mean(np.power(reference-approximation,2), axis = 0))
+    
+    print(f"rmse: {rmse}")
     return rmse