A Solver-Independent API for multi-DOF Applications using Trilinos

Many applications, including fully-coupled reacting flows and multiscale applications, simultaneously resolve multiple degrees of freedom (DOFs). Simultaneously, preconditioning techniques, such as segregated preconditioners for fully-coupled problems, separate variables for efficient sub-operator resolution via fast single DOF solver capabilities such as multigrid or direct solvers that would be ineffective or too expensive if applied to the full problem. In this paper we present an application programmer interface (API) illustrating solver-neutral programming techniques via abstract interfaces, along with Trilinosspecific adapters for these interfaces. Furthermore, we show how to use Trilinos to build highly-parallel, sophisticated multi-DOF preconditioners. For concrete examples, we focus on the application Tramonto, a molecular density functional theories code used for modeling inhomogeneous fluids and EMU, a peridynamics modeling code used to predict the deformation and failure of bodies and structures and dynamic loading. However, the basic principles are easily translated to other important problem domains.