N-body simulation N-body Simulation Testbed              NBodyLab.org

A laboratory for experimenting with small astrophysical N-body simulations,
using a desktop GRAPE-6a supercomputer.

Home Simulations NBODY4 GRAPE's NBodyLab More info

Currently featuring Sverre Aarseth's NBODY4, triple, chain and NBODY6 simulation software

        Feb 2007: 3-body simulations with relativistic effects.
        Aug 2006: Small-n simulations and perturbations, for 3 and 4 bodies.
        July 2006: Introduction to Running Simulations with NBODY4 and NBODY6 (35 pages).
        July 2006: NBODY6 output examples and binaries for Windows and Mac OS.
        Nov 2005: Evolution of dominant binary option, overview and simulation run.
        Oct 2005: Astronomical Society of the Pacific abstract, paper and poster.
        Aug 2005: "NBODY4 on the web" announcement.

GRAPE-6A A GRAPE-6a supercomputer board, running at 120 Gflops peak, powers this site's N-body simulations. It was provided by astrophysicist Prof. Jun Makino of Tokyo University, lead designer of the GRAPE hardware and six-time winner of the annual international Gordon Bell Prize competition for fastest supercomputer performance.

For over 40 years Dr. Sverre Aarseth of Cambridge University has pioneered the field of direct N-body simulations. His 2003 book, the work of a craftsman, describes a lifetime of research, his codes series NBODY1 through NBODY6, and a history of N-body simulation techniques and scientific applications. His software with source code is freely available. NBODY4 has been tested and refined for over 10 years with GRAPE-family hardware.

Examples of NBODY4 Simulation Results

Getting Started

Look over the example simulations above (at the end of each run is a link to an animation applet). Carefully review the introduction to NBODY4 simulations and run some simulations. Read about the GRAPE supercomputers and timing comparisons.

This information may help you justify acquisition of GRAPE-6a. NBODY4 running with a GRAPE-6a may be beneficial for research and teaching.

To do more on your own PC, download NBODY6 (which does not require a GRAPE), the introductory manual, get Sverre’s book and start doing science. NBODY6 is suitable for laptops and workstations. It has been widely used to simulate realistic star clusters and is well documented in both the code distribution and in Aarseth's book.

The NBodyLab overview describes the four-year development of NBodyLab by Vicki Johnson.

To sign up for news, get help or request permission for longer simulations, write to nbodylab@interconnect.com.