Module Gpr_interfaces.Specs.Deriv.Eval

module Eval: Gpr_interfaces.Specs.Eval 
Derivatives always require evaluation functions

module Kernel: Gpr_interfaces.Specs.Kernel 
Kernel used for evaluation
module Inducing: sig .. end
Signature for evaluating inducing inputs
module Input: sig .. end
Signature for evaluating single inputs
module Inputs: sig .. end
Signature for evaluating multiple inputs