Struct SearchConfig 

pub struct SearchConfig {
    pub k: usize,
    pub budget: Cost,
    pub tsb: bool,
    pub max_nodes: usize,
    pub ranking: Ranking,
}

Search parameters.

Build it with ..SearchConfig::default() so that new fields keep their defaults: k = 10, budget = 32 (two ordinary edits’ worth of cost), tsb = true, max_nodes = 100_000, ranking = Ranking::Coarse.

Fields

k: usize

Number of results wanted.

budget: Cost

Largest accepted edit cost (fixed point, 16 = one edit).

tsb: bool

Use the subtree-signature lower bound (on by default).

It never changes the results of a search that finishes within max_nodes, only how much work is done; if the node limit stops a search, both modes return a correct prefix of the same ranked list, but its length can differ. In docs/benchmarks/tsb-default.md it expanded about a third fewer trie nodes and lowered p95 latency by about a fifth (one machine, one corpus). The per-node data it reads is built by Trie::build whatever this flag says, so turning it off saves no memory; set tsb: false to compare or to measure the plain bound.

max_nodes: usize

Hard limit on expanded trie nodes.

ranking: Ranking

How results are ordered.

Implementations

impl SearchConfig

pub fn high_recall() -> Self

An opt-in configuration that trades speed for recall: the default settings with budget = 48 (three ordinary edits’ worth of cost). It sets the subtree bound on explicitly (tsb = true, which does not change the results and is also the default).

On the benchmark in docs/benchmarks/recall-preset.md (300 Birkbeck typo pairs, one machine, median of three runs) it found the right word more often than the default at every dictionary size, at the price of expanding several times more trie nodes per query and a higher latency; the measured numbers are in that file. Measure it on your own dictionary before relying on it. The maximum accepted budget is 64 (see SearchError::BudgetTooLarge); 64 is not offered as a preset because its measured cost grows much faster than its gain.

use keyhammer::search::SearchConfig;
let cfg = SearchConfig { k: 5, ..SearchConfig::high_recall() };
assert_eq!(cfg.budget, 48);
assert!(cfg.tsb);

Trait Implementations

impl Clone for SearchConfig

fn clone(&self) -> SearchConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SearchConfig

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

Formats the value using the given formatter.

impl Default for SearchConfig

fn default() -> Self

Returns the “default value” for a type.