XSEDE12contest repulsive gravity

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Problems involving a large number of objects where everything interacts with everything else is found throughout science, from the very small to the very large and a lot in between. This class of problems is called a n-body problem.

Required/Recommended Knowledge

Problem Description

Consider a universe in which gravity includes a repulsive force at close distances, such that:


How large would alpha need to be in order for the collapse of a 200,000 solar mass cluster initially spread out over 5000 light years to be significantly altered? Users should implement a standard N-body code with the above force law, modified to run in parallel using MPI. A solution should include graphical and statistical interpretation of simulation results.

If we didn’t make gravity a bit repulsive, you would have been able to find codes throughout the Net. In fact there is even one on every version of the BCCD.

You are welcome to obtain code from the web you can legally use, such as GalaxSee from the BCCD, and modify it using our modified gravitational equation.


Your report should include a description of the steps taken by the team in working to create your program. You will need to supply your program, including references to any code you have borrowed, and proof of the legality of your use of it, Be sure to include what you mean by significant alteration of the 200,000 solar mass cluster, as well as your interpretation of results from running your code.

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