Struct hyperlog_simd::plusplus::HyperLogLogPlusPlus

pub struct HyperLogLogPlusPlus {
    pub registers: Box<[u8; 1048576]>,
}

An enhanced HyperLogLog data structure, often termed HyperLogLog++, for estimating the cardinality of a dataset without storing individual elements.

Fields

registers: Box<[u8; 1048576]>

Registers used for maintaining the cardinality estimate. The number of registers (M) impacts precision and memory usage.

Implementations

impl HyperLogLogPlusPlus

pub fn new() -> Self

Constructs a new instance of HyperLogLog++ with all registers initialized to zero.

Returns

A new HyperLogLogPlusPlus instance.

pub fn add<T: Hash>(&mut self, item: T)

Adds an item to the HyperLogLog++. This will update the registers based on the hash of the item but won’t store the item itself.

Parameters

• item: The item to be added. It should implement the Hash trait.

pub fn estimate(&self) -> f64

Estimates the cardinality or unique count of the items added to the HyperLogLog++.

Returns

An approximate count (as f64) of unique items added.

pub fn merge(&mut self, other: &HyperLogLogPlusPlus)

Merges the state of another HyperLogLog++ instance into this one. This is useful for combining the cardinality estimates of two separate datasets.

Parameters

• other: The other HyperLogLogPlusPlus instance whose state is to be merged into this one.

Trait Implementations

impl Clone for HyperLogLogPlusPlus

fn clone(&self) -> HyperLogLogPlusPlus

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HyperLogLogPlusPlus

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for HyperLogLogPlusPlus

fn default() -> Self

Creates a default instance of HyperLogLogPlusPlus.

This is equivalent to calling HyperLogLogPlusPlus::new().

Examples

let hll = HyperLogLogPlusPlus::default();
// ... use the `hll` instance ...

impl<'de> Deserialize<'de> for HyperLogLogPlusPlus

fn deserialize<D>(deserializer: D) -> Result<HyperLogLogPlusPlus, D::Error>where D: Deserializer<'de>,

Deserializes data to construct a HyperLogLogPlusPlus instance.

The data is expected to contain a registers field in a specific serialized format. The CompressedRegistersVisitor is used to assist in this deserialization process.

impl From<[u8; 1048576]> for HyperLogLogPlusPlus

fn from(registers: [u8; 1048576]) -> Self

Creates a HyperLogLogPlusPlus instance from a given array of registers.

Arguments

• registers: An array of u8 representing the internal state of the HyperLogLogPlusPlus.

impl Serialize for HyperLogLogPlusPlus

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>where S: Serializer,

Serializes the HyperLogLogPlusPlus instance.

The registers field will be serialized in a format suitable for transmission or storage using the serialize_registers function.