Add WordPieceTrainer

tokenizers/src/models/bpe/trainer.rs

@@ -319,11 +319,8 @@ impl BpeTrainer {
 
         (words, counts)
     }
-}
 
-impl Trainer for BpeTrainer {
-    /// Train a BPE model
-    fn train(&self, word_counts: HashMap<String, u32>) -> Result<Box<dyn Model + Sync>> {
+    pub fn train(&self, word_counts: HashMap<String, u32>) -> Result<BPE> {
         let mut word_to_id: HashMap<String, u32> = HashMap::new();
         let mut id_to_word: Vec<String> = vec![];
 
@@ -463,14 +460,22 @@ impl Trainer for BpeTrainer {
         }
         self.finalize_progress(&progress, merges.len());
 
-        Ok(Box::new(BPE::new(
+        Ok(BPE::new(
             word_to_id,
             merges
                 .into_iter()
                 .enumerate()
                 .map(|(index, (pair, new_id))| (pair, (index as u32, new_id)))
                 .collect(),
-        )))
+        ))
+    }
+}
+
+impl Trainer for BpeTrainer {
+    /// Train a BPE model
+    fn train(&self, word_counts: HashMap<String, u32>) -> Result<Box<dyn Model + Sync>> {
+        let bpe = self.train(word_counts)?;
+        Ok(Box::new(bpe))
     }
 
     /// Process a bunch of tokens, counting them

tokenizers/src/models/wordpiece/mod.rs

@@ -9,6 +9,9 @@ use std::{
     path::{Path, PathBuf},
 };
 
+mod trainer;
+pub use trainer::*;
+
 #[derive(Debug)]
 pub enum Error {
     MissingUnkToken,

tokenizers/src/models/wordpiece/trainer.rs

@@ -0,0 +1,97 @@
+use super::WordPiece;
+use crate::models::bpe::{BpeTrainer, BpeTrainerBuilder};
+use crate::tokenizer::{Model, Result, Trainer};
+use std::collections::{HashMap, HashSet};
+
+#[derive(Default)]
+pub struct WordPieceTrainerBuilder {
+    bpe_trainer_builder: BpeTrainerBuilder,
+}
+
+impl WordPieceTrainerBuilder {
+    /// Constructs a new `WordPieceTrainerBuilder`
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Set the expected minimum frequency
+    pub fn min_frequency(mut self, frequency: u32) -> Self {
+        self.bpe_trainer_builder = self.bpe_trainer_builder.min_frequency(frequency);
+        self
+    }
+
+    /// Set the vocabulary size
+    pub fn vocab_size(mut self, size: usize) -> Self {
+        self.bpe_trainer_builder = self.bpe_trainer_builder.vocab_size(size);
+        self
+    }
+
+    /// Set whether to show progress
+    pub fn show_progress(mut self, show: bool) -> Self {
+        self.bpe_trainer_builder = self.bpe_trainer_builder.show_progress(show);
+        self
+    }
+
+    /// Set the special tokens
+    pub fn special_tokens(mut self, tokens: Vec<String>) -> Self {
+        self.bpe_trainer_builder = self.bpe_trainer_builder.special_tokens(tokens);
+        self
+    }
+
+    /// Set whether to limit the alphabet
+    pub fn limit_alphabet(mut self, limit: usize) -> Self {
+        self.bpe_trainer_builder = self.bpe_trainer_builder.limit_alphabet(limit);
+        self
+    }
+
+    /// Set the initial alphabet
+    pub fn initial_alphabet(mut self, alphabet: HashSet<char>) -> Self {
+        self.bpe_trainer_builder = self.bpe_trainer_builder.initial_alphabet(alphabet);
+        self
+    }
+
+    /// Set the continuing_subword_prefix
+    pub fn continuing_subword_prefix(mut self, prefix: String) -> Self {
+        self.bpe_trainer_builder = self.bpe_trainer_builder.continuing_subword_prefix(prefix);
+        self
+    }
+
+    /// Set the end_of_word_suffix
+    pub fn end_of_word_suffix(mut self, suffix: String) -> Self {
+        self.bpe_trainer_builder = self.bpe_trainer_builder.end_of_word_suffix(suffix);
+        self
+    }
+
+    /// Constructs the final BpeTrainer
+    pub fn build(self) -> Result<WordPieceTrainer> {
+        let bpe_trainer = self.bpe_trainer_builder.build()?;
+        Ok(WordPieceTrainer { bpe_trainer })
+    }
+}
+
+#[derive(Default)]
+pub struct WordPieceTrainer {
+    bpe_trainer: BpeTrainer,
+}
+
+impl WordPieceTrainer {
+    pub fn builder() -> WordPieceTrainerBuilder {
+        WordPieceTrainerBuilder::default()
+    }
+
+    pub fn train(&self, word_counts: HashMap<String, u32>) -> Result<WordPiece> {
+        let bpe = self.bpe_trainer.train(word_counts)?;
+        Ok(WordPiece::from_bpe(&bpe))
+    }
+}
+
+impl Trainer for WordPieceTrainer {
+    fn train(&self, word_counts: HashMap<String, u32>) -> Result<Box<dyn Model + Sync>> {
+        let wp = self.train(word_counts)?;
+        Ok(Box::new(wp))
+    }
+
+    fn process_tokens(&self, mut words: &mut HashMap<String, u32>, tokens: Vec<String>) {
+        self.bpe_trainer.process_tokens(&mut words, tokens)
+    }
+}