  Modern graphics processing units (GPUs) lead to a major increase in the
performance of the computation of astrophysical simulations. Owing to the
different nature of GPU architecture compared to traditional central processing
units (CPUs) such as x86 architecture, existing numerical codes cannot be
easily migrated to run on GPU. Here, we present a new implementation of the
numerical method smooth particle hydrodynamics (SPH) using CUDA and the first
astrophysical application of the new code: the collision between Ceres-sized
objects. The new code allows for a tremendous increase in speed of
astrophysical simulations with SPH and self-gravity at low costs for new
hardware. We have implemented the SPH equations to model gas, liquids and
elastic, and plastic solid bodies and added a fragmentation model for brittle
materials. Self-gravity may be optionally included in the simulations and is
treated by the use of a Barnes-Hut tree. We find an impressive performance gain
using NVIDIA consumer devices compared to our existing OpenMP code. The new
code is freely available to the community upon request.
