ARKODE: A Flexible IVP Solver Infrastructure for One-step Methods

We describe the ARKODE library of one-step time integration methods for ordinary differential equation (ODE) initial-value problems (IVPs). In addition to providing standard explicit and diagonally implicit Runge--Kutta methods, also supports designed treat additive splittings IVP, including implicit-explicit (ImEx) multirate infinitesimal (MRI) methods. present role within SUNDIALS suite nonlinear solver libraries, core infrastructure utilities common large classes as well its use ``time stepper'' modules enabling easy incorporation novel algorithms into library. Numerical results show example increasing complexity, highlighting algorithmic flexibility afforded through this infrastructure, include a larger multiphysics application leveraging multiple features from SUNDIALS.