added flatten, moved edit_distance to the right place
This commit is contained in:
Sander Hautvast
parent
d907001acd
commit
294158a640
8 changed files with 153 additions and 293 deletions
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@ -1,99 +0,0 @@
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// sandbox, to be removed
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use unicode_segmentation::UnicodeSegmentation;
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//could also be powers of 2 that are combined using bitwise-or
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// enum Backtrace {
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// LEFT,
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// DOWN,
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// DIAGONAL,
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// }
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struct Element {
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value: usize,
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// backtraces: Vec<Backtrace>,
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}
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impl Element {
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fn new() -> Self {
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Self {
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value: 0,
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// backtraces: Vec::new(),
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}
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}
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}
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pub fn get_levenshtein_distance(word1: &str, word2: &str) -> usize {
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get_edit_distance_table(word1, word2)[word1.len()][word2.len()].value
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}
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// non recursive implementation requires a table
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// my guess is that this is more efficient (should check)
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fn get_edit_distance_table(word1: &str, word2: &str) -> Vec<Vec<Element>> {
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// create table
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let mut table = Vec::new();
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for _ in 0..=word1.len() {
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let mut row = Vec::new();
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for _ in 0..=word2.len() {
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row.push(Element::new())
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}
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table.push(row);
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}
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// set the boundaries
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for i in 0..=word1.len() {
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table[i][0].value = i;
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}
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for i in 1..=word2.len() {
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table[0][i].value = i;
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}
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for (i1, g1) in word1.graphemes(true).enumerate() {
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for (i2, g2) in word2.graphemes(true).enumerate() {
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let d_del = table[i1][i2 + 1].value + 1; //deletion
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let d_ins = table[i1 + 1][i2].value + 1; //insertion
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let d_sub = table[i1][i2].value + (if g1 == g2 { 0 } else { 2 }); // substitution
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let min = usize::min(d_del, usize::min(d_ins, d_sub));
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let element = table[i1 + 1].get_mut(i2 + 1).unwrap();
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element.value = min;
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// if d_del == min {
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// element.backtraces.push(Backtrace::DOWN);
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// }
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// if d_ins == min {
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// element.backtraces.push(Backtrace::LEFT);
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// }
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// if d_sub == min {
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// element.backtraces.push(Backtrace::DIAGONAL);
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// }
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}
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}
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table
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}
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#[cfg(test)]
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mod tests {
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use super::{get_edit_distance_table, get_levenshtein_distance};
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#[test]
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fn test_get_levenshtein_distance() {
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assert_eq!(get_levenshtein_distance("intention", "execution"), 8);
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}
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#[test]
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fn test_get_edit_distance_table() {
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// example from Stanford NLP course: https://youtu.be/kgcEaoM_QJA
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let word1 = "intention";
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let word2 = "execution";
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let outcome: [[usize; 10]; 10] = [[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [1, 2, 3, 4, 5, 6, 7, 6, 7, 8], [2, 3, 4, 5, 6, 7, 8, 7, 8, 7], [3, 4, 5, 6, 7, 8, 7, 8, 9, 8], [4, 3, 4, 5, 6, 7, 8, 9, 10, 9],
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[5, 4, 5, 6, 7, 8, 9, 10, 11, 10], [6, 5, 6, 7, 8, 9, 8, 9, 10, 11], [7, 6, 7, 8, 9, 10, 9, 8, 9, 10], [8, 7, 8, 9, 10, 11, 10, 9, 8, 9], [9, 8, 9, 10, 11, 12, 11, 10, 9, 8]];
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let tab = get_edit_distance_table(word1, word2);
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for (rowindex, row) in tab.iter().enumerate() {
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for (colindex, element) in row.iter().enumerate() {
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assert_eq!(outcome[rowindex][colindex], element.value);
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}
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}
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}
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}
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@ -1,4 +1,3 @@
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mod edit_distance; // to be removed
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mod ngrams;// to be removed
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pub mod lm;
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pub mod util;
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pub mod metrics;
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@ -1 +1 @@
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mod preprocessing;
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pub mod preprocessing;
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52
src/metrics/distance.rs
Normal file
52
src/metrics/distance.rs
Normal file
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@ -0,0 +1,52 @@
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// sandbox, to be removed
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use unicode_segmentation::UnicodeSegmentation;
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pub(crate) struct Element {
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pub(crate) value: usize,
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}
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impl Element {
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fn new() -> Self {
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Self {
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value: 0,
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}
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}
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}
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// non recursive implementation requires a table
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// my guess is that this is more efficient (should check)
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pub(crate) fn get_edit_distance_table(word1: &str, word2: &str) -> Vec<Vec<Element>> {
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// create table
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let mut table = Vec::new();
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for _ in 0..=word1.len() {
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let mut row = Vec::new();
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for _ in 0..=word2.len() {
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row.push(Element::new())
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}
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table.push(row);
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}
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// set the boundaries
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for i in 0..=word1.len() {
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table[i][0].value = i;
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}
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for i in 1..=word2.len() {
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table[0][i].value = i;
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}
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for (i1, g1) in word1.graphemes(true).enumerate() {
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for (i2, g2) in word2.graphemes(true).enumerate() {
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let d_del = table[i1][i2 + 1].value + 1; //deletion
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let d_ins = table[i1 + 1][i2].value + 1; //insertion
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let d_sub = table[i1][i2].value + (if g1 == g2 { 0 } else { 2 }); // substitution
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let min = usize::min(d_del, usize::min(d_ins, d_sub));
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let element = table[i1 + 1].get_mut(i2 + 1).unwrap();
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element.value = min;
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}
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}
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table
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}
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33
src/metrics/mod.rs
Normal file
33
src/metrics/mod.rs
Normal file
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@ -0,0 +1,33 @@
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pub mod distance;
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pub fn edit_distance(s1: &str, s2: &str) -> usize {
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distance::get_edit_distance_table(s1, s2)[s1.len()][s2.len()].value
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_get_levenshtein_distance() {
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assert_eq!(edit_distance("intention", "execution"), 8);
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}
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#[test]
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fn test_get_edit_distance_table() {
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// example from Stanford NLP course: https://youtu.be/kgcEaoM_QJA
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let word1 = "intention";
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let word2 = "execution";
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let outcome: [[usize; 10]; 10] = [[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [1, 2, 3, 4, 5, 6, 7, 6, 7, 8], [2, 3, 4, 5, 6, 7, 8, 7, 8, 7], [3, 4, 5, 6, 7, 8, 7, 8, 9, 8], [4, 3, 4, 5, 6, 7, 8, 9, 10, 9],
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[5, 4, 5, 6, 7, 8, 9, 10, 11, 10], [6, 5, 6, 7, 8, 9, 8, 9, 10, 11], [7, 6, 7, 8, 9, 10, 9, 8, 9, 10], [8, 7, 8, 9, 10, 11, 10, 9, 8, 9], [9, 8, 9, 10, 11, 12, 11, 10, 9, 8]];
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let tab = distance::get_edit_distance_table(word1, word2);
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for (rowindex, row) in tab.iter().enumerate() {
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for (colindex, element) in row.iter().enumerate() {
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assert_eq!(outcome[rowindex][colindex], element.value);
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}
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}
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}
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}
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179
src/ngrams.rs
179
src/ngrams.rs
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@ -1,179 +0,0 @@
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// sandbox, to be removed
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use std::cmp::Ordering;
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use std::collections::BTreeMap;
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#[derive(Debug, Eq, Ord)]
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pub struct NGram(Vec<&'static str>);
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impl NGram {
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pub fn new(elements: Vec<&'static str>) -> Self {
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Self {
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0: elements
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}
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}
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pub fn new_bigram(element1: &'static str, element2: &'static str) -> Self {
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Self {
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0: vec![element1, element2]
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}
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}
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pub fn new_trigram(element1: &'static str, element2: &'static str, element3: &'static str) -> Self {
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Self {
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0: vec![element1, element2, element3]
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}
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}
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pub fn tail(&self) -> Self {
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Self {
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0: self.0[1..].to_vec()
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}
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}
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pub fn len(&self) -> usize {
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self.0.len()
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}
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pub fn get(&self, index: usize) -> &'static str {
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unsafe {
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self.0.get_unchecked(index)
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}
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}
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}
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impl PartialEq for NGram {
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fn eq(&self, other: &Self) -> bool {
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if self.len() != other.len() {
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return false;
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} else {
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for (i, element) in self.0.iter().enumerate() {
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if *element != other.get(i) {
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return false;
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}
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}
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}
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true
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}
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}
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impl PartialOrd for NGram {
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fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
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if self.eq(other) {
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Some(Ordering::Equal)
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} else {
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for (i, element) in self.0.iter().enumerate() {
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if let Some(ordering) = element.partial_cmp(&other.get(i)) {
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if ordering != Ordering::Equal {
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return Some(ordering);
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}
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}
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}
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Some(Ordering::Equal)
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}
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}
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}
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pub struct Model {
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word_counts: BTreeMap<&'static str, u32>,
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ngram_counts: BTreeMap<NGram, u32>,
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}
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impl Model {
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pub fn calc_digrams(corpus: Vec<Vec<&'static str>>) -> Self {
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let mut word_counts = BTreeMap::new();
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let mut ngram_counts = BTreeMap::new();
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for sentence in corpus {
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for word in sentence.iter() {
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let count = word_counts.entry(*word).or_insert(0);
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*count += 1;
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}
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for i in 0..sentence.len() - 1 {
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let ngram = NGram::new(vec![sentence[i], sentence[i + 1]]);
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let count = ngram_counts.entry(ngram).or_insert(0);
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*count += 1;
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}
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}
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Self {
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ngram_counts,
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word_counts,
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}
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}
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// only tested for 2-grams, and that's only happy cases
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pub fn p(&self, ngram: NGram) -> Option<f64> {
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// let mut probability = (*self.word_counts.get(ngram.get(0)).unwrap() as f64) / self.word_counts.len() as f64;
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//
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//
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// for index in 0..ngram.len() - 1 {
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// println!("{}", probability);
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//
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//
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//
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// println!("{}", ng_p);
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// probability = ng_p * probability;
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// }
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// println!("{}", probability);
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// Some(probability)
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None
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}
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fn p_ngram(&self, ngram: NGram, intermediate: f64) -> f64 {
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// for index in 0..ngram.len() - 1 {
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// self.ngram_counts.get(&ngram)
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// .map(|count| (*count as f64) / (self.word_counts[ngram.0.get(0).unwrap()] as f64)).unwrap()
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// }
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//
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// if ngram.len() > 2 {
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// println!("{}", intermediate);
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// intermediate * self.pp(ngram.tail(), intermediate) //TODO
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// } else {
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// self.ngram_counts.get(&ngram)
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// .map(|count| (*count as f64) / (self.word_counts[ngram.0.get(0).unwrap()] as f64)).unwrap() //TODO
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// }
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0.0
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_create_model() {
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let corpus = vec![
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vec!["<s>", "I", "am", "Sam", "</s>"],
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vec!["<s>", "Sam", "I", "am", "</s>"],
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vec!["<s>", "I", "do", "not", "like", "eggs", "and", "ham", "</s>"],
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];
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let model = Model::calc_digrams(corpus);
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// assert_eq!(model.p(NGram::new(vec!["<s>", "I"])), Some(0.6666666666666666_f64));
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// assert_eq!(model.p(NGram::new(vec!["Sam", "</s>"])), Some(0.5_f64));
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// assert_eq!(model.p(NGram::new(vec!["<s>", "Sam"])), Some(0.33333333333333333_f64));
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// assert_eq!(model.p(NGram::new(vec!["am", "Sam"])), Some(0.5_f64));
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// assert_eq!(model.p(NGram::new(vec!["I", "am"])), Some(0.6666666666666666_f64));
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println!("{:?}", model.p(NGram::new(vec!["I", "am", "Sam"])));
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}
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#[test]
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fn test_ngram_eq() {
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let n1 = NGram::new(vec!["1", "2"]);
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let n2 = NGram::new(vec!["1", "2"]);
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let n3 = NGram::new(vec!["3", "4"]);
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assert_eq!(n1, n2);
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assert_ne!(n1, n3);
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assert_ne!(n2, n3);
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}
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#[test]
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fn test_ngram_tail() {
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let n1 = NGram::new(vec!["1", "2", "3"]);
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let n2 = NGram::new(vec!["2", "3"]);
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assert_eq!(n1.tail(), n2);
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}
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}
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@ -1,5 +1,5 @@
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pub(crate) mod padding;
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mod ngrams;
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pub(crate) mod ngrams;
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use padding::Padder;
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@ -64,10 +64,14 @@ pub fn trigrams<'a>(sequence: impl Iterator<Item=&'a &'a str> + 'a) -> impl Iter
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ngrams::NGramSequenceIter::new(sequence, 3)
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}
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pub fn everygrams<'a>(sequence: impl Iterator<Item=&'a &'a str> + 'a, n: usize) -> impl Iterator<Item=impl Iterator<Item=&'a &'a str> + 'a> + 'a {
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pub fn everygrams<'a>(sequence: impl Iterator<Item=&'a &'a str> + 'a, n: usize) -> impl Iterator<Item=Box<dyn Iterator<Item=&'a &'a str> + 'a>> + 'a {
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ngrams::EveryGramSequenceIter::everygrams(sequence, n)
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}
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pub fn flatten<'a>(ngrams: impl Iterator<Item=Box<dyn Iterator<Item=&'a &'a str> + 'a>> + 'a) -> impl Iterator<Item=&'a &'a str> + 'a {
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ngrams::FlatteningIter::new(ngrams)
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}
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#[cfg(test)]
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mod tests {
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use std::slice::Iter;
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@ -77,14 +81,14 @@ mod tests {
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fn test_pad_both_ends_default_n2() {
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let text = vec!["a", "b", "c"].into_iter();
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let padded = pad_sequence(text, true, "<s>", true, "</s>", 2);
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should_be_equal_lists(padded, vec!["<s>", "a", "b", "c", "</s>"]);
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should_be_equal_lists2(padded, vec!["<s>", "a", "b", "c", "</s>"]);
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}
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#[test]
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fn test_pad_left() {
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let text = vec!["a", "b", "c"].into_iter();
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let padded = pad_sequence_left(text, "<s>", 2);
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should_be_equal_lists(padded, vec!["<s>", "a", "b", "c"]);
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should_be_equal_lists2(padded, vec!["<s>", "a", "b", "c"]);
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}
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#[test]
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@ -92,14 +96,14 @@ mod tests {
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let text = vec!["a", "b", "c"].into_iter();
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let padded = pad_sequence_right(text, "</s>", 2);
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should_be_equal_lists(padded, vec!["a", "b", "c", "</s>"]);
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should_be_equal_lists2(padded, vec!["a", "b", "c", "</s>"]);
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}
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#[test]
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fn test_pad_both_ends_default_n_eq_3() {
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let text = vec!["a", "b", "c"].into_iter();
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let padded = pad_sequence(text, true, "<s>", true, "</s>", 3);
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should_be_equal_lists(padded, vec!["<s>", "<s>", "a", "b", "c", "</s>", "</s>"]);
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should_be_equal_lists2(padded, vec!["<s>", "<s>", "a", "b", "c", "</s>", "</s>"]);
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}
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#[test]
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@ -107,7 +111,7 @@ mod tests {
|
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let text = vec!["a", "b", "c"].into_iter();
|
||||
let padded = pad_sequence(text, true, "left", true, "right", 2);
|
||||
|
||||
should_be_equal_lists(padded, vec!["left", "a", "b", "c", "right"]);
|
||||
should_be_equal_lists2(padded, vec!["left", "a", "b", "c", "right"]);
|
||||
}
|
||||
|
||||
#[test]
|
||||
|
|
@ -192,8 +196,16 @@ mod tests {
|
|||
should_be_equal_list_of_lists(&mut bigrams, expected)
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_flatten(){
|
||||
let sequence = vec!["a", "b", "c", "d", "e"];
|
||||
let expected = vec!["a", "a", "b", "a", "b", "c", "b", "b", "c", "b", "c", "d", "c", "c", "d", "c", "d", "e"];
|
||||
|
||||
should_be_equal_lists(flatten(everygrams(sequence.iter(), 3)), expected);
|
||||
}
|
||||
|
||||
fn should_be_equal_list_of_lists<'a>(actual: &mut impl Iterator<Item=impl Iterator<Item=&'a &'a str>>, expected: Vec<Iter<&'a str>>) {
|
||||
for (mut actual_outer, expected_outer) in actual.zip(expected.into_iter()) {
|
||||
for (actual_outer, expected_outer) in actual.zip(expected.into_iter()) {
|
||||
for (actual_inner, expected_inner) in actual_outer.zip(expected_outer) {
|
||||
// println!("{} {}", actual_inner, expected_inner);
|
||||
assert_eq!(actual_inner, expected_inner);
|
||||
|
|
@ -201,7 +213,13 @@ mod tests {
|
|||
}
|
||||
}
|
||||
|
||||
fn should_be_equal_lists<'a>(left: impl Iterator<Item=&'a str>, right: Vec<&'a str>) {
|
||||
fn should_be_equal_lists<'a>(left: impl Iterator<Item=&'a &'a str>, right: Vec<&'a str>) {
|
||||
for (left, right) in left.zip(right.into_iter()) {
|
||||
assert_eq!(*left, right);
|
||||
}
|
||||
}
|
||||
|
||||
fn should_be_equal_lists2<'a>(left: impl Iterator<Item=&'a str>, right: Vec<&'a str>) {
|
||||
for (left, right) in left.zip(right.into_iter()) {
|
||||
assert_eq!(left, right);
|
||||
}
|
||||
|
|
|
|||
|
|
@ -19,7 +19,7 @@ impl<'a> Iterator for NGramSequenceIter<'a> {
|
|||
|
||||
fn next(&mut self) -> Option<Self::Item> {
|
||||
return if self.current_ngram.len() == 0 {
|
||||
for i in 0..self.n {
|
||||
for _ in 0..self.n {
|
||||
if let Some(item) = self.sequence.next() {
|
||||
self.current_ngram.push(item);
|
||||
} else {
|
||||
|
|
@ -62,9 +62,10 @@ impl<'a> EveryGramSequenceIter<'a> {
|
|||
impl<'a> Iterator for EveryGramSequenceIter<'a> {
|
||||
type Item = Box<dyn Iterator<Item=&'a &'a str> + 'a>;
|
||||
|
||||
//noinspection DuplicatedCode, hard to deduplicate because of early return
|
||||
fn next(&mut self) -> Option<Self::Item> {
|
||||
if self.current_ngram.len() == 0 {
|
||||
for i in 0..self.n {
|
||||
for _ in 0..self.n {
|
||||
if let Some(item) = self.sequence.next() {
|
||||
self.current_ngram.push(item);
|
||||
} else {
|
||||
|
|
@ -87,3 +88,38 @@ impl<'a> Iterator for EveryGramSequenceIter<'a> {
|
|||
return Some(Box::new(self.current_ngram.clone().into_iter().take(self.current_size)));
|
||||
}
|
||||
}
|
||||
|
||||
pub struct FlatteningIter<'a> {
|
||||
ngrams: Box<dyn Iterator<Item=Box<dyn Iterator<Item=&'a &'a str> + 'a>> + 'a>,
|
||||
current_ngram: Option<Box<dyn Iterator<Item=&'a &'a str> + 'a>>,
|
||||
}
|
||||
|
||||
impl<'a> FlatteningIter<'a> {
|
||||
pub(crate) fn new(ngrams: impl Iterator<Item=Box<dyn Iterator<Item=&'a &'a str> + 'a>> + 'a) -> Self {
|
||||
Self {
|
||||
ngrams: Box::new(ngrams),
|
||||
current_ngram: None,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a> Iterator for FlatteningIter<'a> {
|
||||
type Item = &'a &'a str;
|
||||
|
||||
fn next(&mut self) -> Option<Self::Item> {
|
||||
if self.current_ngram.is_none() {
|
||||
self.current_ngram = self.ngrams.next();
|
||||
}
|
||||
|
||||
while let Some(ref mut current_ngram) = self.current_ngram {
|
||||
let current_item = current_ngram.next();
|
||||
if current_item.is_some() {
|
||||
return current_item;
|
||||
} else {
|
||||
self.current_ngram = self.ngrams.next();
|
||||
}
|
||||
}
|
||||
|
||||
None
|
||||
}
|
||||
}
|
||||
Loading…
Add table
Reference in a new issue