GravTree is a three dimensional N-body integrator. It uses a Barnes-Hut tree to evaluate all force calculations in O(n log n) operations. The tree structure is also used to detect collisions using an instantaneous collision model.
The code is written in C++ and uses pthreads and MPI for parallelisation on shared memory systems and clusters, respectively. Visualisations are done in real time using OpenGL. Simulations of up to half a million particles are possible on a fast desktop computer.
One example is presented in the above flash movie. It shows a close up view of Saturn’s rings. A size distribution of particles as well as one larger body (the blue sphere) are used to form a moonlet. This moonlet might then create a propeller-like structure as observed in the A-ring.
Currently, the source code is not publicly available. However, the plan is to do this as soon as testing and my PhD are finished. If you’re interested in the code, please drop me an e-mail and I will let you know when it get’s published. Note that an iPhone version of this code is freely available and can by downloaded from the AppStore.