Automated Shape Optimization in FEniCS

Shape optimization constrained by partial differential equations(PDEs) are ever-present in the area of scientific computing. The PDEs considered in such applications spans a broad spectrum, ranging from steady state, linear equations, to transient non-linear equations. Efficient algorithms for shape optimization rely on shape derivatives and adjoint PDEs, which, whose derivation and implementation are known to be cumbersome and error-prone. In this talk, we present an approach where this derivation is automatically computed through high-level algorithmic differentiation tool. The shape sensitivities are computed by discrete derivatives of the mesh node sensitivities., for example structural mechanics, computational fluid dynamics and acoustics. A key advantage of our approach is that only the forward problem has to be postulated as input. Then the algorithm creates a computational tape that tracks the propagation of variables and computes corresponding gradients and Hessians. By using the operator overloading approach we inherit the parallelism and performance of the software used to solve the PDE. Our software is overloading the framework FEniCS, which has a high-level Python interface and generates parallel, optimized C++ code. We illustrate the efficiency and robustness of the code by presenting results for several PDEs with a wide range of solution methods.