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feat: Rewrite Automaton generation related code

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This commit is contained in:
Clément Renault 2019-06-27 15:16:32 +02:00
parent 1cb42cbb30
commit 5aa49d232c
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GPG Key ID: 0151CDAB43460DAE
2 changed files with 62 additions and 84 deletions
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59
meilidb-core/src/automaton.rs
View File

@ -1,8 +1,7 @@
use fst::Automaton;
use lazy_static::lazy_static;
use levenshtein_automata::{
LevenshteinAutomatonBuilder as LevBuilder,
DFA, Distance,
DFA,
};
lazy_static! {
@ -11,55 +10,16 @@ lazy_static! {
static ref LEVDIST2: LevBuilder = LevBuilder::new(2, false);
}
pub struct DfaExt {
query_len: usize,
automaton: DFA,
}
impl Automaton for DfaExt {
type State = <DFA as Automaton>::State;
fn start(&self) -> Self::State {
self.automaton.start()
}
fn is_match(&self, state: &Self::State) -> bool {
self.automaton.is_match(state)
}
fn can_match(&self, state: &Self::State) -> bool {
self.automaton.can_match(state)
}
fn will_always_match(&self, state: &Self::State) -> bool {
self.automaton.will_always_match(state)
}
fn accept(&self, state: &Self::State, byte: u8) -> Self::State {
self.automaton.accept(state, byte)
}
}
impl AutomatonExt for DfaExt {
fn eval<B: AsRef<[u8]>>(&self, s: B) -> Distance {
self.automaton.eval(s)
}
fn query_len(&self) -> usize {
self.query_len
}
}
#[derive(Copy, Clone)]
enum PrefixSetting {
Prefix,
NoPrefix,
}
fn build_dfa_with_setting(query: &str, setting: PrefixSetting) -> DfaExt {
fn build_dfa_with_setting(query: &str, setting: PrefixSetting) -> DFA {
use self::PrefixSetting::{Prefix, NoPrefix};
let dfa = match query.len() {
match query.len() {
0 ..= 4 => match setting {
Prefix => LEVDIST0.build_prefix_dfa(query),
NoPrefix => LEVDIST0.build_dfa(query),
@ -72,20 +32,13 @@ fn build_dfa_with_setting(query: &str, setting: PrefixSetting) -> DfaExt {
Prefix => LEVDIST2.build_prefix_dfa(query),
NoPrefix => LEVDIST2.build_dfa(query),
},
};
DfaExt { query_len: query.len(), automaton: dfa }
}
}
pub fn build_prefix_dfa(query: &str) -> DfaExt {
pub fn build_prefix_dfa(query: &str) -> DFA {
build_dfa_with_setting(query, PrefixSetting::Prefix)
}
pub fn build_dfa(query: &str) -> DfaExt {
pub fn build_dfa(query: &str) -> DFA {
build_dfa_with_setting(query, PrefixSetting::NoPrefix)
}
pub trait AutomatonExt: Automaton {
fn eval<B: AsRef<[u8]>>(&self, s: B) -> Distance;
fn query_len(&self) -> usize;
}

87
meilidb-core/src/query_builder.rs
View File

@ -11,8 +11,9 @@ use meilidb_tokenizer::{is_cjk, split_query_string};
use rayon::slice::ParallelSliceMut;
use sdset::SetBuf;
use slice_group_by::GroupByMut;
use levenshtein_automata::DFA;
use crate::automaton::{DfaExt, AutomatonExt, build_dfa, build_prefix_dfa};
use crate::automaton::{build_dfa, build_prefix_dfa};
use crate::distinct_map::{DistinctMap, BufferedDistinctMap};
use crate::criterion::Criteria;
use crate::raw_documents_from_matches;
@ -21,18 +22,38 @@ use crate::{Match, DocumentId, Store, RawDocument, Document};
const NGRAMS: usize = 3;
struct Automaton {
index: usize,
query_index: usize,
query_len: usize,
is_exact: bool,
dfa: DfaExt,
dfa: DFA,
}
impl Automaton {
fn exact(index: usize, dfa: DfaExt) -> Automaton {
Automaton { index, is_exact: true, dfa }
fn exact(query_index: usize, query: &str) -> Automaton {
Automaton {
query_index,
query_len: query.len(),
is_exact: true,
dfa: build_dfa(query),
}
}
fn non_exact(index: usize, dfa: DfaExt) -> Automaton {
Automaton { index, is_exact: false, dfa }
fn prefix_exact(query_index: usize, query: &str) -> Automaton {
Automaton {
query_index,
query_len: query.len(),
is_exact: true,
dfa: build_prefix_dfa(query),
}
}
fn non_exact(query_index: usize, query: &str) -> Automaton {
Automaton {
query_index,
query_len: query.len(),
is_exact: false,
dfa: build_dfa(query),
}
}
}
@ -54,7 +75,7 @@ fn generate_automatons<S: Store>(query: &str, store: &S) -> Result<Vec<Automaton
let synonyms = store.synonyms()?;
for n in 1..=NGRAMS {
let mut index = 0;
let mut query_index = 0;
let mut ngrams = query_words.windows(n).peekable();
while let Some(ngram_slice) = ngrams.next() {
@ -65,7 +86,7 @@ fn generate_automatons<S: Store>(query: &str, store: &S) -> Result<Vec<Automaton
// automaton of concatenation of query words
let normalized = normalize_str(&concat);
let lev = build_dfa(&normalized);
let automaton = Automaton::exact(index, lev);
let automaton = Automaton::exact(query_index, lev);
automatons.push((automaton, normalized));
let has_following_word = ngrams.peek().is_some();
@ -92,11 +113,10 @@ fn generate_automatons<S: Store>(query: &str, store: &S) -> Result<Vec<Automaton
let nb_synonym_words = split_query_string(synonyms).count();
for synonym in split_query_string(synonyms) {
let lev = build_dfa(synonym);
let automaton = if nb_synonym_words == 1 {
Automaton::exact(index, lev)
Automaton::exact(query_index, synonym)
} else {
Automaton::non_exact(index, lev)
Automaton::non_exact(query_index, synonym)
};
automatons.push((automaton, synonym.to_owned()));
}
@ -106,21 +126,34 @@ fn generate_automatons<S: Store>(query: &str, store: &S) -> Result<Vec<Automaton
if n == 1 {
let lev = if not_prefix_dfa { build_dfa(&ngram) } else { build_prefix_dfa(&ngram) };
let automaton = Automaton::exact(index, lev);
let automaton = Automaton::exact(query_index, lev);
automatons.push((automaton, ngram));
}
index += 1;
query_index += 1;
}
}
automatons.sort_unstable_by(|a, b| (a.0.index, &a.1).cmp(&(b.0.index, &b.1)));
automatons.dedup_by(|a, b| (a.0.index, &a.1) == (b.0.index, &b.1));
automatons.sort_unstable_by(|a, b| (a.0.query_index, &a.1).cmp(&(b.0.query_index, &b.1)));
automatons.dedup_by(|a, b| (a.0.query_index, &a.1) == (b.0.query_index, &b.1));
let automatons = automatons.into_iter().map(|(a, _)| a).collect();
Ok(automatons)
}
fn rewrite_matched_positions(matches: &mut [(DocumentId, Match)]) {
for document_matches in matches.linear_group_by_mut(|(a, _), (b, _)| a == b) {
let mut offset = 0;
for query_indexes in document_matches.linear_group_by_mut(|(_, a), (_, b)| a.query_index == b.query_index) {
let word_index = query_indexes[0].1.word_index - offset as u16;
for (_, match_) in query_indexes.iter_mut() {
match_.word_index = word_index;
}
offset += query_indexes.len() - 1;
}
}
}
pub struct QueryBuilder<'c, S, FI = fn(DocumentId) -> bool> {
store: S,
criteria: Criteria<'c>,
@ -184,9 +217,9 @@ where S: Store,
while let Some((input, indexed_values)) = stream.next() {
for iv in indexed_values {
let Automaton { index, is_exact, ref dfa } = automatons[iv.index];
let Automaton { query_index, is_exact, query_len, ref dfa } = automatons[iv.index];
let distance = dfa.eval(input).to_u8();
let is_exact = is_exact && distance == 0 && input.len() == dfa.query_len();
let is_exact = is_exact && distance == 0 && input.len() == query_len;
let doc_indexes = self.store.word_indexes(input)?;
let doc_indexes = match doc_indexes {
@ -197,8 +230,8 @@ where S: Store,
for di in doc_indexes.as_slice() {
if self.searchable_attrs.as_ref().map_or(true, |r| r.contains(&di.attribute)) {
let match_ = Match {
query_index: index as u32,
distance: distance,
query_index: query_index as u32,
distance,
attribute: di.attribute,
word_index: di.word_index,
is_exact,
@ -206,23 +239,15 @@ where S: Store,
char_length: di.char_length,
};
matches.push((di.document_id, match_));
}
}
}
}
// rewrite the matched positions for next criteria evaluations
matches.par_sort_unstable();
for document_matches in matches.linear_group_by_mut(|(a, _), (b, _)| a == b) {
let mut offset = 0;
for query_indexes in document_matches.linear_group_by_mut(|(_, a), (_, b)| a.query_index == b.query_index) {
let word_index = query_indexes[0].1.word_index - offset as u16;
for (_, match_) in query_indexes.iter_mut() {
match_.word_index = word_index;
}
offset += query_indexes.len() - 1;
}
}
rewrite_matched_positions(&mut matches);
let total_matches = matches.len();
let padded_matches = SetBuf::from_dirty(matches);