Added a readme

README.md

@@ -0,0 +1,117 @@
+# Orbital Simulator
+
+A fast N-body orbital mechanics simulator written in Rust.  
+Simulate the motion of celestial bodies under Newtonian gravity, with easy configuration and efficient output for visualization.
+
+---
+
+## Features
+
+- **N-body simulation**
+- **Configurable initial conditions** via JSON
+- **Binary trajectory files**
+- **Progress bar** 
+- **Unit normalization** 
+- **Ready for visualization** (Coming Soon)
+
+---
+
+## Getting Started
+
+### Prerequisites
+
+- [Rust](https://www.rust-lang.org/tools/install) (edition 2021 or later)
+- Python (optional, for animation/visualization)
+
+### Build
+
+```bash
+cargo build --release
+```
+
+### Run
+
+```bash
+cargo run --release -- \
+  --config path/to/your_config.json \
+  --time 30d \
+  --step-size 10.0 \
+  --output-file trajectory.bin
+```
+
+**Arguments:**
+
+- `--config` (required): Path to your JSON config file with initial body states.
+- `--time` (required): Total simulation time (e.g. `10s`, `5m`, `2h`, `100d`).
+- `--step-size`: Simulation step size in seconds (default: `10.0`).
+- `--output-file` (required): Where to save the trajectory data.
+- `--steps-per-save`: How often to update the progress bar and save (default: `1000`).
+
+---
+
+## Configuration
+
+The config file is a JSON file describing the initial state of each body.  
+Examples provided in config/
+
+```json
+{
+  "bodies": [
+    {
+      "name": "BodyName",
+      "mass": 1e10, //kg
+      "position": [0.0, 0.0, 0.0], //meters
+      "velocity": [0.0, 0.0, 0.0] // m/s
+    },
+    ...
+  ]
+}
+```
+
+- **Units:**  
+  - Mass: kilograms (kg)  
+  - Position: meters (m)  
+  - Velocity: meters per second (m/s)
+
+---
+
+## Output
+
+- The simulator writes binary snapshots of the system state to the output file using [bincode](https://docs.rs/bincode/).
+- Each snapshot contains the simulation time and the real (de-normalized) positions, velocities, and masses of all bodies.
+
+---
+
+## Animation
+
+Coming soon.
+
+---
+
+## Extending
+
+- Add more bodies or change initial conditions in the config file.
+- Adjust step size and simulation time for accuracy/performance trade-offs.
+- The code is modular and ready for extension (e.g., new force laws, output formats, or integrators).
+
+---
+
+## License
+
+MIT License
+
+---
+
+## Acknowledgments
+
+- [Rust](https://www.rust-lang.org/)
+- [glam](https://crates.io/crates/glam) for fast vector math
+- [clap](https://crates.io/crates/clap) for CLI parsing
+- [indicatif](https://crates.io/crates/indicatif) for progress bars
+- [serde](https://crates.io/crates/serde) and [bincode](https://crates.io/crates/bincode) for serialization
+
+---
+
+## Author
+
+- Thomas Faour

src/simulator.rs

@@ -49,7 +49,7 @@ impl Simulation {
         for i in 0..steps {
             debug!("Step: {}", i);
             self.reset_accelerations();
-            self.caclulate_accelerations();
+            self.calculate_accelerations();
             self.step_bodies();
             if i % self.steps_per_save == 0 {
                 //save the state
@@ -68,7 +68,7 @@ impl Simulation {
         }
     }
 
-    fn caclulate_accelerations(&mut self) {
+    fn calculate_accelerations(&mut self) {
         let r_hat_over_r3 = self.get_rhat_over_r_three();
         let n = self.bodies.len();
         for i in 0..(n-1) {