anchor.diff:          else failwithf "Cannot subtract Tensors with shapes %A, %A" a.Shape b.Shape
       static member (-) (a:Tensor, b) = a - a.Create(b)
       static member (-) (a, b:Tensor) = b.Create(a) - b
  +    member t1.Sub(t2:Tensor) = t1 - t2
  +    member t1.Sub(t2) = t1 - t1.Create(t2)
   
       static member (*) (a:Tensor, b:Tensor) =
           if a.Shape = b.Shape then
  
positive.code:         else failwithf "Cannot add Tensors with shapes %A, %A" a.Shape b.Shape
      static member (+) (a:Tensor, b) = a + a.Create(b)
      static member (+) (a, b:Tensor) = b.Create(a) + b
  
      static member (-) (a:Tensor, b:Tensor) =
          if a.Shape = b.Shape then
  
negative.code:         else failwithf "Cannot divide Tensors with shapes %A, %A" a.Shape b.Shape
      static member (/) (a:Tensor, b) = a / a.Create(b)
      static member (/) (a, b:Tensor) = b.Create(a) / b
      member t1.Div(t2:Tensor) = t1 / t2
      member t1.Div(t2) = t1 / t1.Create(t2)
  
      static member Pow (a:Tensor, b:Tensor) =
          if a.Shape = b.Shape then
  