  We provide a description of the SNSPH code--a parallel 3-dimensional
radiation hydrodynamics code implementing treecode gravity, smooth particle
hydrodynamics, and flux-limited diffusion transport schemes. We provide
descriptions of the physics and parallelization techniques for this code. We
present performance results on a suite of code tests (both standard and new),
showing the versatility of such a code, but focusing on what we believe are
important aspects of modeling core-collapse supernovae.
