nBody (alpha)

ALL CODE IS PROVIDED WITHOUT WARRANTY. THERE IS NO GUARANTEE THAT THE PHYSICS IS CORRECT.

Contents:

1. Introduction
2. Methods
3. Compiling and Running
4. Version Log
5. Contact
6. Recommended Reading


1. Introduction

nBody was written by me as a project to help learn computational methods for simulating structure such as galaxies, dark matter halos etc. Clearly such simulations are usually run on supercomputers not an Intel Core-2 Duo 2.13GHz desktop! As such this code is intended as a way of learning simulation methods/techniques rather that creating my own mini universe. Despite this I have tried and continue to try and make the code as efficient as possible so that at least fairly interesting test cases can be considered.

This code has also served as a way for me to learn c and so the programming style is probably not very good. This is something I hope to improve with time. Any guidance would be very much welcomed! 

Version control - stable snapshots will start with 0.1.0 continuing to 0.x.0 for later states where additional functionality has been added. All versions 0.x.y.z (x!=0) should therefore be considered unstable. If I ever get to the point where I am confident in the physics being correct I will release as version 1.x.y.z. Until such a point the code should be considered as alpha! I claim no warranty of it being correct!


2. Methods

The main code written in c deals with the physics outputting data to STDOUT so that it can be piped into a data file. The data file is then analysed with a python script from which plots can be created to view energy and particle paths.


3. Compiling and Running

To get the code either download it directly from the github site or use git to make a local mirror.

The code uses the stdio.h, math.h and stdlib.h libraries which should be installed by default on Linux systems. The python script uses python-numpy and python-matplotlib. To install these on a Debian/apt based systems run;

	apt-get install python-numpy python-matplotlib
	
To run n_body2 first you need to compile it. The easiest way is with make or gcc;

	make nBody -lm

or 

	gcc nBody.c -lm
	
Then to run the code;

	./nBody > data.txt
	
This will also then pipe the data into a text file called data.txt.

The python script analysis.py will then parse the data file and create a set of plots showing the motion of the particles in a directory, plots. Then using ffmpeg you can make these images into a movie;

	ffmpeg -r 20 -qscale 2 -i plots/Plot%05d.png Sim4h.mp4

where -r defines the framerate and -qscale the quality (where 1 is best and higher is worse).


4. Version Log





5. Contact

Please contact me at astrolinux22 'at' gmail 'dot' com if you have any queries, tips or corrections.





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git push --mirror https://github.com/astrolinux22/n_body2
git pull https://github.com/astrolinux22/n_body2