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API: KLL

Status: Ready

Purpose

Approximate quantile estimation with rank-error guarantees.

Type/Struct

  • KLL<T = f64>
  • Cdf

Constructors

fn default() -> Self
fn init_kll(k: i32) -> Self
fn init(k: usize, m: usize) -> Self

Insert/Update

fn update(&mut self, val: &T)
fn update_data_input(&mut self, val: &DataInput) -> Result<(), &'static str> // KLL<f64> only
fn clear(&mut self)

Query

fn quantile(&self, q: f64) -> f64
fn rank(&self, x: f64) -> usize
fn count(&self) -> usize
fn cdf(&self) -> Cdf

// Cdf
fn quantile(&self, x: f64) -> f64
fn query(&self, p: f64) -> f64
fn quantile_li(&self, x: f64) -> f64
fn query_li(&self, p: f64) -> f64

Merge

fn merge(&mut self, other: &KLL<T>)

Serialization

fn serialize_to_bytes(&self) -> Result<Vec<u8>, RmpEncodeError>
fn deserialize_from_bytes(bytes: &[u8]) -> Result<Self, RmpDecodeError>

Examples

use asap_sketchlib::{KLL, DataInput};

let mut kll = KLL::<i64>::init_kll(200);
kll.update(&10);
kll.update(&20);
let q50 = kll.quantile(0.5);
assert!(q50 >= 10.0);
use asap_sketchlib::{KLL, DataInput};

let mut kll = KLL::<f64>::init_kll(200);
kll.update_data_input(&DataInput::F64(10.0)).unwrap();
kll.update_data_input(&DataInput::F64(20.0)).unwrap();
let q50 = kll.quantile(0.5);
assert!(q50 >= 10.0);

Caveats

  • KLL<T> is generic over numeric types implementing NumericalValue.
  • update_data_input exists only on KLL<f64> for type-erased DataInput call paths.
  • Query-side APIs still return f64.

Status

Production-usable quantile sketch with comprehensive tests.