anchor.diff:  
       /// Add scalar `b` to vector `a`
       static member (+) (a:DV, b:D) =
  -        let inline ff(a, b) = GlobalConfig.Float32Backend.Add_S_V(b, a)
  +        let inline ff(a, b) = Backend().Add_S_V(b, a)
           let inline fd(a, b) = a + b
           let inline df_da(cp, ap, at) = at
           let inline df_db(cp, bp, bt) = DV.OfArray(Array.create a.Length bt)
  
positive.code:                             | Mul_Dot_DV_DVCons(a, cons) -> pushRec ((bx (d.A * cons) a) :: t)
                              | Sum_DV(a) -> pushRec ((bx (DV.create a.Length d.A) a) :: t)
                              | L1Norm_DV(a) -> pushRec ((bx (d.A * DV.Sign a.P) a) :: t)
                              | L2NormSq_DV(a) -> pushRec ((bx (d.A * (D 2.f) * a.P) a) :: t)
                              | L2Norm_DV(a) -> pushRec ((bx ((d.A / d.P) * a.P) a) :: t)
                              | Item_DV(a, i) -> a.A <- DV.AddItem(a.A, i, d.A); pushRec ((bx DV.Zero a) :: t)
                              | Sum_DM(a) -> pushRec ((bx (DM.create a.Rows a.Cols d.A) a) :: t)
                              | Item_DM(a, i, j) -> a.A <- DM.AddItem(a.A, i, j, d.A); pushRec ((bx DM.Zero a) :: t)
                              | Det_DM(a) -> pushRec ((bx (d.T * d.P * DM.Transpose(DM.Inverse(a))) a) :: t) // Check this
                              | ReLU_D(a) -> pushRec ((bx (d.A * ((D.Sign(a.P) + 1.f) / 2.f)) a) :: t)
                              | Sigmoid_D(a) -> pushRec ((bx (d.A * d.P * (1.f - d.P)) a) :: t) // d.P = D.Sigmoid(a.P)
                              | LogSumExp_DV(a) -> pushRec ((bx ((d.A / exp d.P) * exp a.P) a) :: t) // d.P = DV.LogSumExp(a.P)
                              | FixedPoint_D(b, bfirst, aprev, alast) ->
                                  // Christianson (1994)
                                  let imax = DiffSharp.Config.GlobalConfig.FixedPointMaxIterations
                                  let eps = D DiffSharp.Config.GlobalConfig.Float32FixedPointEpsilon
  
                                  let mutable i = 0
  
  
negative.code: 
      /// Element-wise addition of `a` and `b`
      static member (+) (a:DM, b:DM) =
          let inline ff(a, b) = Backend().Add_M_M(a, b)
          let inline fd(a, b) = a + b
          let inline df_da(cp, ap, at) = at
          let inline df_db(cp, bp, bt) = bt
  