N-Body Simulator

This project creates a QWidget used for simulating a gravitational system of N bodies in two dimensions.

Table of contents

• Installation
• Usage
• About
• Features

Installation

This widget was created using Python v3.8, and using CMake v3.12. These versions are a minimum requirement. It is also recommended that you create a virtual environment and activate it before starting the installation process.

The first step is to clone the code in this repository using git:

git clone git@github.com:robertapplin/N-Body-Simulations.git

Then install the python environment requirements and Qt dependencies using pip:

pip install -r requirements.txt

Next, from within the project source directory, build and install the project. If this command fails, try running it as admin.

python setup.py install

The n-body-simulations package can now be found in the site-packages of your virtual environment.

Building Locally

You can also build the code locally from git bash, from your source directory and with your virtual environment activated. Pass the following flags to the first cmake command below: -DPYTHON_EXECUTABLE, Dpybind11_DIR, DCMAKE_INSTALL_PREFIX, DCMAKE_INSTALL_LIBDIR

cmake --preset=vs-debug .
cmake --build ../build

Usage

From python, you can now import and open the widget as follows:

from n_body_simulations.startup import startup_widget

startup_widget()

It is also possible to embed the widget into an existing interface.

About

The purpose of this project was to develop my programming skills by creating a maintainable and well-tested cross-platform application. In this project I have created a simulator for N-Body gravitational systems which allows the collision and merging of bodies. The docs folder contains example *.txt files which can be loaded into this widget.

The following units have been used for this project:

Quantity	Measured in	Unit
Mass	Solar masses	M*
Position	Astronomical units	au
Time	Days	d
Velocity	Astronomical units per day	au/d

Features

The widget has several options which are found above the data table:

Button	Description
	Load a *.txt file containing initial parameters for an N-Body-Simulation.
	Save the initial parameters of an N-Body-Simulation to a *.txt file.
	Remove the selected bodies from the simulation.
	Add bodies to the simulation.
	Adjust the time step and duration of the simulation.
	Show or hide position labels and velocity arrows on the plot.
	Turn on interactive mode, allowing you to interact with the bodies on the plot.
	Stop the simulation.
	Play or Pause the simulation.

The widget also includes an interactive plot where you can:

Image	Description
	Adjust the colour and name used to represent a body.
	Adjust the position of a body by dragging the body on the interactive plot.
	Adjust the velocity of a body by dragging the velocity arrow on the interactive plot.