holos-tda 0.9.0

Vietoris-Rips persistence and checked degree-Rips modules
Documentation 
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//! Union-find with path compression and union by rank.

pub struct UnionFind {
    parent: Vec<usize>,
    rank: Vec<u8>,
}

impl UnionFind {
    pub fn new(n: usize) -> Self {
        Self {
            parent: (0..n).collect(),
            rank: vec![0; n],
        }
    }

    pub fn find(&mut self, mut x: usize) -> usize {
        let mut root = x;
        while self.parent[root] != root {
            root = self.parent[root];
        }
        while self.parent[x] != root {
            let next = self.parent[x];
            self.parent[x] = root;
            x = next;
        }
        root
    }

    /// Merge two trees by rank. `x` and `y` must both be roots.
    pub fn link(&mut self, x: usize, y: usize) {
        debug_assert!(self.parent[x] == x && self.parent[y] == y);
        if self.rank[x] < self.rank[y] {
            self.parent[x] = y;
        } else {
            self.parent[y] = x;
            if self.rank[x] == self.rank[y] {
                self.rank[x] += 1;
            }
        }
    }
}