sig
type t =
[ `Inducing_hyper of Cov_se_fat.Inducing_hyper.t
| `Log_hetero_skedasticity of Cov_se_fat.Dim_hyper.t
| `Log_multiscale_m05 of Cov_se_fat.Inducing_hyper.t
| `Log_sf2
| `Proj of Cov_se_fat.Proj_hyper.t ]
end