Crate sketches_rust

source ·
Expand description

This crate provides a direct port of the Java DDSketch implementation to Rust.

Usage

Add multiple samples to a DDSketch and invoke the get_value_at_quantile method to pull any quantile from 0.0 to 1.0.

    use self::sketches_rust::DDSketch;
    let mut d = DDSketch::collapsing_lowest_dense(0.02,100).unwrap();
    d.accept(1.0);
    d.accept(2.0);
    d.accept(3.0);
    let c = d.get_count();
    assert_eq!(c, 3.0);
    let q = d.get_value_at_quantile(0.5).unwrap();
    assert!(q < 2.01 && q > 1.99);

Also you could merge other DDSketch:

    use self::sketches_rust::DDSketch;
    let mut d1 = DDSketch::collapsing_lowest_dense(0.02,100).unwrap();
    d1.accept(1.0);
    d1.accept(2.0);
    d1.accept(3.0);
    assert_eq!(3.0,  d1.get_count());
    let mut d2 = DDSketch::collapsing_lowest_dense(0.02,100).unwrap();
    d2.accept(1.0);
    d2.accept(2.0);
    d2.accept(3.0);
    assert_eq!(3.0,  d2.get_count());
    d2.merge_with(&mut d1).unwrap();
    assert_eq!(6.0,  d2.get_count());

Encode to bytes:

    use self::sketches_rust::{DDSketch};
    let mut d = DDSketch::unbounded_dense(2e-2).unwrap();
    d.accept(1.0);
    d.accept(2.0);
    d.accept(3.0);
    d.accept(4.0);
    d.accept(5.0);
    println!("encode: {:?}", d.encode().unwrap());

Decode from bytes:

    use self::sketches_rust::{DDSketch};
    let mut input = vec![
        2, 42, 120, 57, 5, 47, 167, 240, 63, 0, 0, 0, 0, 0, 0, 0, 0, 13, 50, 130, 1, 2, 136, 32, 0,
        3, 0, 0, 0, 3, 0, 2, 0, 0, 3, 3, 2, 2, 3, 3, 2, 0, 0, 0, 0, 2, 0, 2, 2, 2, 4, 4, 132, 64,
        0, 4, 2, 0, 2, 2, 3, 132, 64, 4, 132, 64, 4, 2, 2, 0, 6, 4, 6, 132, 64, 2, 6,
    ];
    let mut d = DDSketch::decode(&input).unwrap();
    assert_eq!(d.get_count(), 100.0);

Structs

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