ChaNGa - An adaptable N-body and gas dynamics code.
              (Charm N-body GrAvity solver)

For documentation, see the web site: https://github.com/N-BodyShop/changa/wiki/ChaNGa

For more help, subscribe to the list [email protected].

Please cite the following papers when publishing results using ChaNGa:

P. Jetley, F. Gioachin, C. Mendes, L. V. Kale, and T. R. Quinn. Massively parallel cosmological simulations with ChaNGa. In Proceedings of IEEE International Parallel and Distributed Processing Symposium 2008, 2008.

P. Jetley, L. Wesolowski, F. Gioachin, L. V. Kale, and T. R. Quinn. Scaling hierarchical n-body simulations on gpu clusters. In Proceedings of the 2010 ACM/IEEE International Conference for High Performance Computing, Networking, Storage and Analysis, SC ’10, Washington, DC, USA, 2010. IEEE Computer Society.

Menon, H., Wesolowski, L., Zheng, G., Jetley, P., Kale, L., Quinn, T., Governato, F., 2015. Adaptive Techniques for Clustered N-Body Cosmological Simulations, Computational Astrophysics and Cosmology, 2, 1.

To compile ChaNGa first compile Charm++ or get a precompiled version. When building Charm++, there is a special target "ChaNGa" which will build all the necessary libraries. Then to compile ChaNGa itself, run:

./configure make (or gmake)

The executable ChaNGa will be created together with the submit script charmrun (for most machines). Configure takes the usual options and also the "--enable-cooling" option to specify cooling for gas simulations.

To run the code:

./charmrun +p ChaNGa <param.file> [ additional options ]

This will work on many machines, and can either be run directly or be submitted through the local scheduler. However, on some machines the application will need to be submitted manually.

More information is available in the online wiki: https://github.com/N-BodyShop/changa/wiki

Several test simulations are included in subdirectories:

A small globular cluster simulation is included in teststep. This simulation can give a quick sanity check that the gravity code is operating correctly.

A small cosmological simulation is included in testcosmo.

A small shock tube (gas only) simulation is included in testshock.

A small gas collapse simulation is included in testcollapse.

For simple performance benchmarking, arbitrary size simulations can be created using the tools in testdata.

An example simulation that generates movie frames is included in movie. See the director.README in that directory for movie-making options.

ACKNOWLEDGMENTS

The development of ChaNGa was supported by a National Science Foundation ITR grant PHY-0205413 to the University of Washington, and NSF ITR grant NSF-0205611 to the University of Illinois. Contributors to the program include: Philip Chang Ronak Buch Jaemin Choi Jesse Ashworth Michael Tremmel Abhishek Gupta Aditya Devarakonda Alexander Fry Amit Sharma Ben Keller Celso Mendes Charlotte Christensen Collin J. Sutton Edgar Solomonik Evan Ramos Filippo Gioachin Gengbin Zheng Grame Lufkin Greg Stinson Harshit Dokania Harshitha Menon Iryna Butsky Isaac Backus James Wadsley Jianqiao Liu Jillian Bellovary Joachim Stadel Lukasz Wesolowski Michael Robson Orion Lawlor Peng Wang Phil Miller Pritish Jetley Robel Geda Rok Roskar Sayantan Chakravorty Sijing Chen Simon Garcia De Gonzalo Spencer Wallace Thomas Quinn Tim Haines Viraj Paropkari Yanhua Sun