N-Body-simulation

Introduction

This project is a 3D N-Body simulation, it takes in a JSON file as input and creates a CSV file as output, that contains the id, mass, position and velocity of each Planet, along with collision information. The input file can be in one of two formats both starting with the simulation info. First format, the user specifies every planet in the sim and their starting values (Mass, Position, Velocity), the other format generates a random simulation given values of counts of Planets, Mass Range, Position Range, Velocity Range

Features

This N-Body simulation is in 3 Dimensions, and can hadle anywhere from 2-100000 Planets, It handles collisions by merging the two Planets, their mass, and conserving momentum. The program uses Leapfrog integration to keep accurate data. At > 200 planets the program uses an Octree to improve performance.

File Format

{ "simulation": { "step": 0.01, "steps": 10000, "G": 1.0, "softening": 0.1 }, "planets": [ { "mass": 1000.0, "radius": 10.0, "position": [0, 0, 0], "velocity": [0, 0, 0] }, { "mass": 1.0, "radius": 1.0, "position": [100, 0, 0], "velocity": [0, 4.7, 0] } ] }

Or Generative Sim File Format

{ "simulation": { "step": 0.01, "steps": 10000, "G": 1.0, "softening": 0.1, }, "generation": { "count": 100, "massRange": [1, 100], "radiusRange": [1, 10], "positionRange": [-500, 500], "velocityRange": [-2, 2], } }

How to run

In the Command Line: java "input_file_name"

For Gen Sim: java "input_file_name" --gen