Normalized Sobol indices:
==========================
['x2']:           0.442411
['x1']:           0.313905
['x1', 'x3']:     0.243684
['x1', 'x2']:     0.000000
['x2', 'x3']:     0.000000
['x3']:           0.000000

Average derivatives:
==========================
['x1']:           8.47e-06
['x2']:          -3.25e-07
['x3']:          -1.51e-06
