sig
type t
val calc :
Gpr_interfaces.Sigs.Eval.Co_variance_predictor.t ->
sigma2:float ->
Gpr_interfaces.Sigs.Eval.Input.t -> Gpr_interfaces.Sigs.Eval.Variance.t
val get : ?predictive:bool -> Gpr_interfaces.Sigs.Eval.Variance.t -> float
end