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https://github.com/oadultradeepfield/gravigo

A porting of C++ N-body orbit simulation to Go with native plotting and goroutines for concurrency.
https://github.com/oadultradeepfield/gravigo

golang goroutines gravity simulation

Last synced: 9 days ago
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A porting of C++ N-body orbit simulation to Go with native plotting and goroutines for concurrency.

Host: GitHub
URL: https://github.com/oadultradeepfield/gravigo
Owner: oadultradeepfield
License: mit
Created: 2025-02-01T04:02:52.000Z (10 days ago)
Default Branch: main
Last Pushed: 2025-02-01T04:19:45.000Z (10 days ago)
Last Synced: 2025-02-01T05:19:55.257Z (10 days ago)
Topics: golang, goroutines, gravity, simulation
Language: Go
Homepage:
Size: 4.75 MB
Stars: 0
Watchers: 1
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md
- License: LICENSE

Awesome Lists containing this project

README

# Gravigo

Gravigo is a Go program for simulating the orbit of N objects under their mutual gravitation. It is a porting of my two continuous previous projects written in C++. Visit [this repository](https://github.com/oadultradeepfield/n-body-orbit-simulation) for more details. Gravigo is meant to be the exact replica but with native support for orbit plotting without relying on Python's Matplotlib. It also supports concurrent simulation using goroutines to allow more efficient processing.

## Development Roadmap

- [x] Port the previous C++ implementation to Go with additional project structure improvement.
- [x] Parallelize the loop with goroutines to make the iterations run concurrently.
- [ ] Migrate the Python matplotlib visualization to [Gonum Plot](https://github.com/gonum/plot) for native experiences.

## Getting Started

1. Begin by cloning the repository and navigate to the respective directory

```bash
git clone https://github.com/oadultradeepfield/gravigo
cd gravigo
```

2. Download all dependencies using the following command:

```bash
go mod tidy
```

3. Make sure you have Go installed. This project is built using Go version 1.23.4. You can run the simulation using the following command line:

```bash
go run cmd/simulation/main.go config.json
```

Please refer to the below section to set up the configuration file `config.json`,

## Usage

1. From the previous section, you have seen how to run the simulation using the command line. Note that the configuration file is mandatory as it contains the data of the objects you would like to examine. Below is the example of how you can set up the file:

```json
{
"simulator_config": {
"gravitational_constant": 6.6743e-11,
"dt": 1000,
"total_time": 3.16e7,
"output_file": "example_sun_earth_lagrangian_points.txt"
},
"coordinate_type": "spherical",
"bodies": [
{
"_name": "Sun",
"mass": 1.989e30,
"position": [0.0, 0.0, 1.5707963268],
"velocity": [0.0, 0.0, 0.0]
},
{
"_name": "Earth",
"mass": 5.972e24,
"position": [1.496e11, 0.0, 1.5707963268],
"velocity": [0.0, 2.9788e4, 0.0]
},
{
"_name": "L1",
"mass": 6500,
"position": [1.481e11, 0.0, 1.5707963268],
"velocity": [0.0, 2.9489e4, 0.0]
},
{
"_name": "L2",
"mass": 6500,
"position": [1.511e11, 0.0, 1.5707963268],
"velocity": [0.0, 3.0087e4, 0.0]
},
{
"_name": "L3",
"mass": 6500,
"position": [1.496e11, 3.1415926536, 1.5707963268],
"velocity": [0.0, 2.978e4, 0.0]
},
{
"_name": "L4",
"mass": 6500,
"position": [1.496e11, 1.0471975512, 1.5707963268],
"velocity": [0.0, 2.978e4, 0.0]
},
{
"_name": "L5",
"mass": 6500,
"position": [1.496e11, -1.0471975512, 1.5707963268],
"velocity": [0.0, 2.978e4, 0.0]
}
]
}
```

The parameter `dt` is the time step size used to estimate the integration. The smaller ones would generally yield more accurate results but require longer to process. In addition, using large values will sometimes cause incorrect orbit shapes since the error is high. If you use Cartesian coordinates, the three components of `position` and `velocity` should be simply X, Y, and Z. For spherical coordinates, they are R, Theta, and Phi. In this project, Theta is measured from the X-axis, while Phi is measured from the Z-axis down to the XY plane.

2. As you have previously seen, you can run the simulation using the following command line:

```bash
go run cmd/simulation/main.go config.json
```

The output from this command is a `.txt` file located at the specified path in `config.json`:

```
0.057882, 0.000005, -0.000000
149599980722.057831, 89363998.228348, -0.763470
148099980905.314911, 88466998.245267, -0.755815
151099980527.170044, 90260998.210362, -0.771125
-149599980722.042450, -89339999.755764, -0.763470
74722619652.576691, 129602053710.282852, -0.763470
74877361068.657425, -129512713712.054565, -0.763470
...
```

Each line corresponds to the Cartesian coordinates of each object in the same order as the input. There are seven objects in the above example, so the line will repeat for the same objects every seven lines at the new time step.

3. (Optional) To test the performance of your machine when simulating a large number of objects, you can run the following command:

```bash
go run cmd/benchmark/main.go
```

On my machine (M3 Macbook Air with 8-Core CPU), the following results were logged to the console:

```
2025/02/01 18:37:11 Starting benchmark...
2025/02/01 18:37:11 Simulating 10 bodies...
2025/02/01 18:37:11 N=10: Time taken: 120ms
2025/02/01 18:37:11 Simulating 50 bodies...
2025/02/01 18:37:11 N=50: Time taken: 302ms
2025/02/01 18:37:11 Simulating 250 bodies...
2025/02/01 18:37:13 N=250: Time taken: 1.507s
2025/02/01 18:37:13 Simulating 1250 bodies...
2025/02/01 18:37:26 N=1250: Time taken: 12.907s
2025/02/01 18:37:26 Simulating 6250 bodies...
2025/02/01 18:40:51 N=6250: Time taken: 3m25.483s
2025/02/01 18:40:51 Benchmark completed.
```

4. To be updated after integrating Gonum Plot.

## License

This project is licensed under the MIT License. See the [`LICENSE`](/LICENSE) file for details.