  Additive Runge-Kutta methods designed for preserving highly accurate
solutions in mixed-precision computation were proposed and analyzed in [8].
These specially designed methods use reduced precision or the implicit
computations and full precision for the explicit computations. We develop a
FORTRAN code to solve a nonlinear system of ordinary differential equations
using the mixed precision additive Runge-Kutta (MP-ARK) methods on IBM POWER9
and Intel x86\_64 chips. The convergence, accuracy, runtime, and energy
consumption of these methods is explored. We show that these MP-ARK methods
efficiently produce accurate solutions with significant reductions in runtime
(and by extension energy consumption).
