chull 0.2.3

Convex hull approximation
Documentation 
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# chull

![Build Status](https://github.com/daidanretsu/chull/workflows/Rust/badge.svg) [![crates.io](https://img.shields.io/crates/v/chull.svg)](https://crates.io/crates/chull)

[Documentation](https://docs.rs/chull/)
![](img/usagi.png)
Convex hull approximation for rust based on [Quick hull](http://citeseerx.ist.psu.edu/viewdoc/summary;jsessionid=C57E2269B0D64504B97E8469F6A1315D?doi=10.1.1.117.405).
Available in 3-D or 2-D for now.
## Examples

```rust
use chull::ConvexHull;
let p1 = vec![1.0, 1.0, 1.0];
let p2 = vec![1.0, 1.0, -1.0];
let p3 = vec![1.0, -1.0, 1.0];
let p4 = vec![1.0, -1.0, -1.0];
let p5 = vec![-1.0, 1.0, 1.0];
let p6 = vec![-1.0, 1.0, -1.0];
let p7 = vec![-1.0, -1.0, 1.0];
let p8 = vec![-1.0, -1.0, -1.0];
let p9 = vec![0.0, 0.0, 0.0];
// threshold is used internally to determine whether a point is above or below the surface.
let threshold = 0.001;
let points = vec![p1, p2, p3, p4, p5, p6, p7, p8, p9];
let cube = ConvexHull::try_new(&points, threshold, None).unwrap();
assert_eq!(cube.volume(), 8.0);
let (_v,i) = cube.vertices_indices();
assert_eq!(i.len(), 6 * 2 * 3);
```
## If the results are inaccurate

If the calculation results are inaccurate due to rounding errors, an error may occur. In such cases, the use of integer types such as [```BigInt```](https://docs.rs/num-bigint/) may improve the result.
```rust
use chull::ConvexHull;
use num_bigint::{BigInt, ToBigInt};
let p1 = vec![1.0, 0.0, 0.0];
let p2 = vec![0.0, 0.001, 0.0];
let p3 = vec![0.0, 0.0, 0.00001];
let p4 = vec![-1.0, 0.0, 0.0];
let p5 = vec![0.0, -0.001, 0.0];
let p6 = vec![0.0, 0.0, -0.00001];
let points_float = vec![p1, p2, p3, p4, p5, p6];
let mut points_int = Vec::new();
for point_float in &points_float{
    points_int.push(point_float.iter().map(|x| (x*1_000_000.0).to_bigint().unwrap()).collect::<Vec<_>>());
}
// Since there is no rounding error when using BigInt, the threshold value can be zero.
let octahedron = ConvexHull::try_new(&points_int, 0, None).unwrap();
// The following are likely to be errors
//let octahedron = ConvexHull::try_new(&points_float, std::f32::EPSILON, None).unwrap();
```

License: MIT/Apache-2.0