n-body-solver in c++

A simple implementation of an n-body-solver written in c++ by using direct force calculation. Leapfrog is used as an integrating scheme. A simulation of the solar system and JFC (Jupiter-Family-Comets) is shown here:

This program was developed on CLion (with CMake) on macOS and uses openMPI to parallelise the calculation. The program will read some configuration parameters from the file input/input.conf which can look as follows:

path=../input/solar_jfc_rev.dat
steps=100000
dt=86400
save_interval=10
ignore_bodies=62
G=6.67408e-11

If dt=0 is specified, the program will calculate dt according to the internal function. assuming that the binary nbody is located in a bin or cmake-build-debug folder. The parameter ignore_bodies determines how many bodies are ignored when calculating the force on other bodies. This is useful for small bodies like satellites, comets or asteroids that do not exert a force on large bodies such as planets. For ignore_bodies=62 the last 62 bodies of the dataset are ignored. This code has also been tested on a CRAY supercomputer. There is a makefile in the bin folder.

There are two example initial conditions in the input folder, milky_way_andromeda.csv (dubinski dataset) and solar_jfc.csv (solar system with jupiter-family-comets), both with their corresponding input.conffiles.

Usage:

First create a input/input.conf file based on the two examples. Then build the project using CMake or the Makefile in bin folder. Then run:

mpirun -np {num_cores} nbody