SPACE BALLS PROGRAM DESCRIPTION Chris Pan, Brendan DeMilt

The program "Space Balls" is Brendan's creative name for the Barnes Hutt algorithm. This algorithm is an n-body space simulation that has nlogn complexity. The algorithm groups nearby bodies and approximates them as a single body. To tell if 2 nodes can be grouped, use the test s/d < 0.5, s being the width of the region represented by internal node, and d is distance between body and the center of mass.

The data structure we use is the quad-ST-tree, the node has a planet, and its corresponding square representing 2d space. The root node represents the whole plane, with children splitting it up evenly into 4 squares. The symbol table is utilized as the key stores a square plane where each node value is a planet body in itself. We chose this program because space is amazing and this is a lot more fun than a zooming algorithm

ENJOY

More information on the barnes hut algorithm: http://arborjs.org/docs/barnes-hut

For an interactive link, check out: http://www.stefanom.org/bh-tree/

TO RUN: compile: javac SpaceBalls.java

run: java SpaceBalls < galaxyformation.txt

a good time change value is .1 as any large number will be too quick for you to see