# fdhess.m

Returns the finite-difference Hessian of a 3D array using a finite difference scheme with a user-specified number of stencil points and a unit grid spacing. The dimensions of the 3D array are assumed to be ordered as [X Y Z].

## Syntax

    H=fdhess(A,nstenc)


## Arguments

    A      - a 3D array with dimensions ordered as [X Y Z]

nstenc - number of points inthe finite difference stencil,
periodic boundary conditions are used


## Outputs

    H      - a 3x3 cell array of 3D arrays ordered in the
following way:

{d2A_dxdx  d2A_dxdy  d2A_dxdz
d2A_dydx  d2A_dydy  d2A_dydz
d2A_dzdx  d2A_dzdy  d2A_dzdz}