N-Body Simulation

Simulating the dynamics of several bodies moving simultaneously under the influence of gravitational forces in 2D. It includes both sequential and parallel implementations, along with a real-time GTKMM GUI for visualization.

Files Overview

• nbody.hpp : Delares the Body structure; the Quad and QuadNode classes for Barnes-Hut; and the NBodySimulation class with all simulation methods (sequential, parallel, and Barnes-Hut).
• nbody.cpp : Implements the simulation logic:
  • Time-step update (sequential and parallel)
  • Force computations (sequential and parallel), including:
    • A direct parallel approach using atomics
    • A direct parallel approach using thread-local arrays
    • The parallel Barnes-Hut algorithm
• sim.cpp : Starts the GUI using GTKMM and allows switching between simulation modes (solar system, 3-body and 6-body problems, N random bodies, etc.). Particles are rendered live in a sequential manner because Cairo, the rendering library, is not thread-safe. However, the particle data is updated concurrently in parallel threads to improve responsiveness. Also implements the accuracy and efficiency analyses.

How to Run

1. Prerequisites

Make sure you have:

• A C++20-compatible compiler
• GTKMM 3 library

2. Build the Project

Download all the source files into a single directory and compile using: make

3. Run the Simulation

Run the simulation as follows:

• ./nbody or ./nbody -sim1 to simulate the solar system (by default)
• ./nbody -sim3 to simulate a 3-body problem
• ./nbody -sim6 to simulate a 6-body problem
• ./nbody -rand N to simulate a random system with N bodies
• ./nbody -comp to test accuracy
• ./nbody -eff N to test efficiency with N random bodies
• ./nbody -help to see all call options

GUI Controls and Interactive Features

Once the simulation window opens, you can interact with the system in real time using:

• Spacebar: Pause/Resume the simulation
• + / - or Zoom In / Zoom Out buttons: Zoom into or out of the simulation view
• Mouse Drag: Click and drag with the left mouse button to pan the simulation view
• Up / Down Arrow Keys or Faster / Slower buttons: Increase or decrease the timestep (i.e., simulation speed)
• R or Reset button: Reset the simulation to its initial state

Simulation Preview

Solar System

3-Body Triangle

6-Body Hexagon

50 Random Bodies

500 Random Bodies

5000 Random Bodies