theta parameters
The theta parameters in the function call of covariance functions should be defined more precisely. In the details of some covariance functions the parametrization is defined as (range, sill, [smoothness], nugget). It should be "partial sill" instead of sill. Furthermore, the default values are set to be (1, [1], 0), which does not coincide with the parametrization stated before, i.e. one default value is missing.
Cheers, Jakob