turning off kernel nugget

Author: thartland

src/Drivers/hiopbbpy/BnBDriverEX.py

@@ -124,7 +124,7 @@ def _evaluate(self, x: np.ndarray) -> np.ndarray:
   y_train = problem.evaluate(x_train)
 
   gp_model = smtKRG(theta, problem.xlimits, nx)
-  gp_model.set_nugget(1.e-9)
+  #gp_model.set_nugget(1.e-9)
   gp_model.train(x_train, y_train)