Figure 8

Iterative hybrid solver. The fixed point iteration alternates between discrete optimization problems (1) with solutions in the data-induced space \(\mathcal{D}\) (red triangles), and variational problems (2) with solutions in the physics-conforming space \(\mathcal{P}\) (blue circles), the latter being accomplished by a modified finite element solver. [Adapted from [10], Fig. 3.] The algorithm is an instance of the hard constraints design pattern, see paragraph 4.1.4.1, in particular Fig. 7a