anchor.diff:      /// Original value and gradient-vector product (directional derivative) of a vector-to-scalar function `f`, at point `x`, along vector `v`
       let inline gradv' f x v =
           let i = GlobalTagger.Next
  -        Array.map2 (dualIPT i) x v |> f |> tuple
  +        Array.map2 (makeDFIPT i) x v |> f |> tuple
   
       /// Gradient-vector product (directional derivative) of a vector-to-scalar function `f`, at point `x`, along vector `v`
       let inline gradv f x v =
  
positive.code:     let inline laplacian' f (x:_[]) =
          let i = GlobalTagger.Next
          let a = Array.init x.Length (fun j ->
                                          let xd = standardBasis x.Length j |> Array.map2 (dualIPT i) x
                                          fVStoSS j f xd
                                          |> diff
                                          <| xd.[j])
          (x |> Array.map dual |> f, Array.sumBy tangent a)
  
      /// Laplacian of a vector-to-scalar function `f`, at point `x`
      let inline laplacian f x =
  
negative.code:     /// Original value and Jacobian-vector product of a vector-to-vector function `f`, at point `x`, along vector `v`
      let inline jacobianv' f x v =
          let i = GlobalTagger.Next
          Array.map2 (makeDFIPT i) x v |> f |> Array.map tuple |> Array.unzip
  
      /// Jacobian-vector product of a vector-to-vector function `f`, at point `x`, along vector `v`
      let inline jacobianv f x v =
  