HyperLogLog - Rust

Distinct-count cardinality estimator. ~16 KB of state gives ~1% standard error up to 10^9 distinct.

Part of the submillisecond.com cookbook. Zero external dependencies; std only.

Install

[dependencies]
subms-hyperloglog = "0.4"

Quickstart

cargo test --release
cargo run --example demo

Public API

• pub struct HyperLogLog
• pub fn new(precision: u32) -> Self
• pub fn precision(&self) -> u32
• pub fn register_count(&self) -> u32
• pub fn add(&mut self, key: &str)
• pub fn estimate(&self) -> f64
• pub fn merge(&mut self, other: &Self) -> Result<(), &'static str>

Files

• src/lib.rs - implementation.
• tests/ - integration tests; correctness, edge cases, property/stress.
• examples/demo.rs - stdout walkthrough.
• examples/perf_main.rs - bench entry (behind the harness feature).

License

Dual-licensed under MIT OR Apache-2.0.