FEniCS implementation of the finite element method introduced in the paper:
E. Burman, M. Nechita and L. Oksanen, Unique continuation for the Helmholtz equation using stabilized finite element methods, J. Math. Pures Appl., 2019. https://doi.org/10.1016/j.matpur.2018.10.003
The code also contains numerical experiments regarding the (order of) convergence of the method.