This is Nbody6++GPU - Beijing version, an N-body star cluster simulation code, maintained by Rainer Spurzem (spurzem/at/nao.cas.cn) and team. The starting commits of this repo put all old versions of Nbody6++GPU from Dec 2017 into Git system for version control.
The code is an offspring of Sverre Aarseth's direct N-body codes see www.sverre.com .
This is the code suitable for parallel and GPU accelerated runs on supercomputers and workstations.
Manual in doc/nbody6++_manual.pdf
apt-get install libhdf5-openmpi-dev
apt-get install libhdf5-dev ./configure --with-par=b1m --enable-simd=sse --enable-mcmodel=large
make clean ; make -j It is for up to one million bodies with many initial binaries. The configure script written by Long Wang has a multitude of further options, check in it or ask.
Sources are in src/Main/ . Due to urgent bugfixes few routines are later then Dec2020.
After make you find the executable and object files in build/ .
The environment variable OMP_NUM_THREADS has to be set to the desired value of OpenMP threads per MPI process. (Maybe your system has it predefined). I also recommend to set OMP_STACKSIZE=4096M the shell where you run the code.
It is inefficient (and even more error prone) for particle numbers below about 50k-100k particles (depending on hardware). For smaller N you are advised to use Nbody6 and Nbody6GPU for single node/process.
It is recommended to provide a dat.10 file in N-body input format (see manual). Such file can be produced by other prograns, like mcluster.
- https://ui.adsabs.harvard.edu/abs/1999PASP..111.1333A/abstract (Aarseth: NBODY1 to NBODY6)
- https://ui.adsabs.harvard.edu/abs/1999JCoAM.109..407S/abstract (Spurzem on NBODY6++)
- https://ui.adsabs.harvard.edu/abs/2005MNRAS.363..293H/abstract (Hurley+ on SSE/BSE, earlier references therein)
- https://ui.adsabs.harvard.edu/abs/2012MNRAS.424..545N/abstract (Nitadori+: NBODY6GPU)
- https://ui.adsabs.harvard.edu/abs/2015MNRAS.450.4070W/abstract (Wang+: NBODY6++GPU)
- https://ui.adsabs.harvard.edu/abs/2021arXiv210508067K/abstract (Kamlah+: More on current stellar evol.)
- For systems with more than one GPU on one node the association of MPI rank id and GPU bus id is not well defined, will be improved in next version.
- Runs with a million or more bodies and huge numbers of binaries (5% or more) use extreme amounts of computing time for the KS binaries (much much more than should be expected). We work on this.
- On some systems heap and stack management when using OpenMP and MPI together seem to produce very strange errors and segmentation faults. The exact reason is not known; we work on this.
This code and the documentation is given without warranty, hopefully it is helpful. All may contain errors.