module Cov_lin_one:sig..end
k(x, y) = x*inv(P)*y + 1/t^2
logtheta = log(t)
where P is a diagonal matrix containing t^2 along the diagonal.
module Params:sig..end
module Eval:Evalwith type Kernel.params = Params.twith type Inducing.t = matwith type Input.t = vecwith type Inputs.t = mat
module Deriv:Derivwith module Eval = Evalwith type Hyper.t = [ `Log_theta ]