Efficient implementation of low-order-precision smoothed particle hydrodynamics

Smoothed particle hydrodynamics (SPH) method is widely accepted as a flexible numerical treatment for surface boundaries and interactions. High-resolution simulations of hydrodynamic events require high-performance computing (HPC). There is a need for an SPH code that runs efficiently on modern supercomputers involving accelerators such as NVIDIA or AMD graphics processing units. In this work, we applied half-precision, which is widely used in artificial intelligence, to the SPH method. However, improving HPC performance at such low-order precisions is a challenge. An as-is implementation with half-precision will have lower computational cost than that of float/double precision simulations, but also worsens the simulation accuracy. We propose a scaling and shifting method that maintains the simulation accuracy near the level of float/double precision. By examining the impact of half-precision on the simulation accuracy and time-to-solution, we demonstrated that the use of half-precision can improve the computational performance of SPH simulations for scientific purposes without sacrificing the accuracy. In addition, we demonstrated that the efficiency of half-precision depends on the architecture used.