Solid Wave Simulation (swSim) is software that solves heterogeneous, anisotropic elastodynamic equations for ultrasonic NDE simulation. A time-explicit staggered grid finite difference (FD) scheme is employed and solved on graphics processing units (GPUs). Parallelism via the Message Passing Interface (MPI) allows for deployment on a cluster, or on a single computer with one or more GPUs. Wavefield data is output using Visualization Toolkit (VTK) file formats for 3D rendering capabilities via open source tools, and a kernel composition module allows high-level registration of sequences of matrix operations, providing extensibility in equations and physics solved. - View it on GitHub