Struct HyperLogLogBuilder 

pub struct HyperLogLogBuilder<H, W = usize> { /* private fields */ }

Builds a HyperLogLog cardinality-estimator logic.

Implementations

impl HyperLogLogBuilder<BuildHasherDefault<DefaultHasher>>

pub const fn new(num_elements: usize) -> Self

Creates a new builder for a HyperLogLog logic with the default word type (the fixed-size equivalent of usize).

Panics

If n is zero.

impl<H, W: Word> HyperLogLogBuilder<H, W>

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

Sets the desired relative standard deviation.

Note

This is a high-level alternative to Self::log_2_num_reg. 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 log_2_num_reg(self, log_2_num_registers: usize) -> Self

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

Note

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

Arguments

• log_2_num_registers: the logarithm of the number of registers per estimator.

Panics

If log_2_num_registers is less than 4.

pub fn min_log_2_num_reg(&self) -> usize

Returns the minimum value allowed for Self::log_2_num_reg given the current value of Self::num_elements.

pub fn word_type<W2>(self) -> HyperLogLogBuilder<H, W2>

Sets the type W to use to represent backends.

Note that the returned builder will have a different type if W2 is different from W.

See the logic documentation for the limitations on the choice of W2.

pub const fn num_elements(self, num_elements: usize) -> Self

Sets the upper bound on the number of elements.

Panics

If n is zero.

pub fn build_hasher<H2>(self, build_hasher: H2) -> HyperLogLogBuilder<H2, W>

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) -> HyperLogLog<T, H, W>

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.

Panics

If the estimator size in bits is not divisible by the bit width of W.

Trait Implementations

impl<H: Clone, W: Clone> Clone for HyperLogLogBuilder<H, W>

fn clone(&self) -> HyperLogLogBuilder<H, W>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<H: Debug, W: Debug> Debug for HyperLogLogBuilder<H, W>

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

Formats the value using the given formatter.