You should be now familiar with the following topics:
Define an Array, a NekMatrix and a PointsKey in Nektar++.
Use the PointsManager with a PointsKey to get hold of quadrature zeros and
differentiation matrices.
Differentiate a polynomial function in the standard region ξ ∈ [-1,1] using Gauss-Gauss-Legendre and Gauss-Lobatto-Legendre quadrature.
Extend the standard region to a standard quadrilateral region.
Introduce a linear mapping from a general quadrilateral region to the standard quadrilateral region. Evaluate the Jacobian of this mapping and evaluate derivatives in a general straight sided quadrilateral region.