Euler Equation Steady Adjoint
PDESolver currently has the capability to compute the steady adjoint of a boundary functional. Recall the adjoint equation as
\[\frac{\partial \mathcal{L}}{\partial q} = \frac{\partial \mathcal{J}}{\partial q} + \psi^T \frac{\partial \mathcal{R}}{\partial q} = 0\]
where, $\mathcal{L}$ is the Lagrangian for functional $\mathcal{J}$ and $q$ is the solution variable. The adjoint can be computed by calling the function calcAdjoint, which has been described below.