Using AmgX to accelerate a PETSc-based Immersed-Boundary Method code

Our open-source code PetIBM—an immersed boundary method with a fully discrete projection formulation—was written to take advantage of the PETSc library for solving the Poisson system. We have now added the capacity to accelerate the time to solution on CUDA-capable GPU devices using the Nvidia library AmgX. To provide access to AmgX solvers from a PETSc-based code, we developed a wrapper code that converts the data structures between the two libraries. This wrapper code could be useful to other PETSc applications that want to use GPUs via AmgX. Our application of interest is the three- dimensional flow around a flying-snake, to reveal the lift-enhancement mechanisms used by this unconventional glider. We are developing capability to study this problem in Microsoft Azure cloud services.