Problem in the example of parametric elliptic control problem

[annaivagnes]

Describe the bug Training not leading to the expected solution

To Reproduce examples/run_parametric_elliptic_optimal.py

Expected behavior We expect the solution to be close to the PINN solution in paper https://arxiv.org/pdf/2110.13530 (Figure 4)

[dario-coscia]

Maybe #317 is related! I will check and update you :)