Struct HyperLogLog8Builder 

pub struct HyperLogLog8Builder<H, const BETA: bool = true> { /* private fields */ }

Builder for HyperLogLog8 cardinality-estimation logic.

The builder lets you configure:

• the number of registers, either directly (log2_num_regs) or via a target relative standard deviation (rsd);
• the hash function (build_hasher);
• whether LogLog-β bias correction is enabled (beta).

Call build to obtain the configured HyperLogLog8 logic.

Implementations

impl HyperLogLog8Builder<BuildHasherDefault<DefaultHasher>>

pub const fn new() -> Self

Creates a new builder for a HyperLogLog8 logic.

impl<H, const BETA: bool> HyperLogLog8Builder<H, BETA>

pub fn rsd(self, rsd: f64) -> Self

Sets the desired relative standard deviation.

This is a high-level alternative to Self::log2_num_regs. Calling one after the other invalidates the work done by the first one.

Arguments

• rsd: the relative standard deviation to be attained.

Panics

If the resulting number of registers is less than 16 (i.e., rsd is too large).

pub const fn log2_num_regs(self, log2_num_regs: u32) -> Self

Sets the base-2 logarithm of the number of registers.

This is a low-level alternative to Self::rsd. Calling one after the other invalidates the work done by the first one.

Arguments

• log2_num_regs: the logarithm of the number of registers per estimator.

Panics

If log2_num_regs is less than 4.

pub fn beta<const BETA2: bool>(self) -> HyperLogLog8Builder<H, BETA2>

Enables or disables the LogLog-β bias correction in the estimate.

See HyperLogLog8 for details.

pub fn build_hasher<H2>(self, build_hasher: H2) -> HyperLogLog8Builder<H2, BETA>

Sets the BuildHasher to use.

Using this method you can select a specific hasher based on one or more seeds.

pub fn build<T>(self) -> HyperLogLog8<T, H, BETA>

Builds the logic.

The type of objects the estimators keep track of is defined here by T, but it is usually inferred by the compiler.

Trait Implementations

impl<H: Clone, const BETA: bool> Clone for HyperLogLog8Builder<H, BETA>

fn clone(&self) -> HyperLogLog8Builder<H, BETA>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<H: Debug, const BETA: bool> Debug for HyperLogLog8Builder<H, BETA>

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

Formats the value using the given formatter.

impl Default for HyperLogLog8Builder<BuildHasherDefault<DefaultHasher>>

fn default() -> Self

Returns the “default value” for a type.