Struct ReservoirSampler 

pub struct ReservoirSampler { /* private fields */ }

Enhanced reservoir sampling implementation based on Vitter’s algorithm

This is a proper implementation of Algorithm R with optimizations:

• True randomness with seedable RNG for reproducibility
• Optimized skip calculation using geometric distribution
• Memory-efficient storage of sample indices
• Support for weighted sampling

Implementations

impl ReservoirSampler

pub fn new(capacity: usize) -> Self

Create a new reservoir sampler with specified capacity

pub fn seed(capacity: usize, seed: u64) -> Self

Create a new reservoir sampler with custom seed

pub fn process_record(&mut self, record_index: usize) -> bool

Process a new record and decide if it should be included Returns true if the record is selected for the sample

pub fn replacement_slot(&mut self, seen: usize) -> Option<usize>

Which reservoir slot row number seen should replace, if any.

Algorithm R over a full reservoir: the seen-th row of the stream (1-based) replaces a uniformly chosen member with probability capacity / seen, which leaves every row seen so far equally likely to be in the sample. Returns None when the row is not selected.

This is the primitive for sampling rows; process_record tracks indices only and is kept for callers that sample by position.

pub fn get_sample_indices(&self) -> &[usize]

Get current sample as a vector of indices

pub fn sample_size(&self) -> usize

Get current sample size

pub fn is_full(&self) -> bool

Check if reservoir is full

pub fn get_stats(&self) -> &ReservoirStats

Get sampling statistics

pub fn sampling_ratio(&self) -> f64

Calculate current sampling ratio

pub fn reset(&mut self)

Reset the sampler for reuse

pub fn set_seed(&mut self, seed: u64)

Set new seed for reproducible results

pub fn update_efficiency_stats(&mut self)

Update efficiency statistics

Trait Implementations

impl Clone for ReservoirSampler

fn clone(&self) -> ReservoirSampler

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ReservoirSampler

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

Formats the value using the given formatter.