GP model without derivative obs
Checking gradient ...

   analytic   diffs     delta

    2.2001    2.2001    0.0000
   -1.0624   -1.0624   -0.0000

 TolFun reached. Func-count 17. Final f(x)=5.67863. Elapsed time 0.12
GP model with derivative obs
Checking gradient ...

   analytic   diffs     delta

    3.6684    3.6684    0.0000
  -10.3567  -10.3567   -0.0000
    1.1596    1.1596    0.0000

 TolX reached. Func-count 19. Final f(x)=3.15085. Elapsed time 0.17

 gp hyperparameters: 
 
   -1.6957   -0.3805   -4.1351

Demo completed in 0.012 minutes
