I’d like to compute the Hessian for array values and to get

some array with dimension (2,2) but instead I got this

```
julia> hessian(x -> sum(x.^3), [1 2; 3 4]) # uses linear indexing of x
4×4 Array{$Int,2}:
6 0 0 0
0 18 0 0
0 0 12 0
0 0 0 24
```

If I use the 2 x 10 array then I already have 20 x 20 matrix! Can I put the result in the other dimension?

Because my neural network will be very slow as I use hessian in the loss function