GP model without derivative obs
Checking gradient ...

   analytic   diffs     delta

    2.6657    2.6657    0.0000
   -3.7894   -3.7894   -0.0000
    1.6251    1.6251    0.0000

 TolX reached. Func-count 19. Final f(x)=2.89367. Elapsed time 0.17
GP model with derivative obs
Checking gradient ...

   analytic   diffs     delta

    4.3476    4.3476    0.0000
  -13.6379  -13.6379   -0.0000
    4.4016    4.4016   -0.0000

 TolFun reached. Func-count 26. Final f(x)=-8.68413. Elapsed time 0.23

 gp hyperparameters: 
 
   -1.5025   -0.2305   -4.9053

Demo completed in 0.014 minutes
