[Flax] Add T5 pretraining script (#12355)

* fix_torch_device_generate_test * remove @ * add length computatan * finish masking * finish * upload * fix some bugs * finish * fix dependency table * correct tensorboard * Apply suggestions from code review * correct processing * slight change init * correct some more mistakes * apply suggestions * improve readme * fix indent * Apply suggestions from code review Co-authored-by: SaulLu <55560583+SaulLu@users.noreply.github.com> * correct tokenizer * finish * finish * finish * finish Co-authored-by: Patrick von Platen <patrick@huggingface.co> Co-authored-by: SaulLu <55560583+SaulLu@users.noreply.github.com>
2021-06-28 20:11:29 +01:00
parent e277074889
commit 31c3e7e75b
7 changed files with 1014 additions and 16 deletions
--- a/examples/flax/language-modeling/t5_tokenizer_model.py
+++ b/examples/flax/language-modeling/t5_tokenizer_model.py
@@ -0,0 +1,112 @@
+#!/usr/bin/env python3
+import json
+from typing import Iterator, List, Union
+
+from tokenizers import AddedToken, Regex, Tokenizer, decoders, normalizers, pre_tokenizers, trainers
+from tokenizers.implementations.base_tokenizer import BaseTokenizer
+from tokenizers.models import Unigram
+from tokenizers.processors import TemplateProcessing
+
+
+class SentencePieceUnigramTokenizer(BaseTokenizer):
+    """
+    This class is a copy of `DeDLOC's tokenizer implementation <https://github.com/yandex-research/DeDLOC/blob/main/sahajbert/tokenizer/tokenizer_model.py>`__ .
+
+    Custom SentencePiece Unigram Tokenizer with NMT, NKFC, spaces and lower-casing characters normalization
+    Represents the Unigram algorithm, with the pretokenization used by SentencePiece
+    """
+
+    def __init__(
+        self,
+        replacement: str = "▁",
+        add_prefix_space: bool = True,
+        unk_token: Union[str, AddedToken] = "<unk>",
+        eos_token: Union[str, AddedToken] = "</s>",
+        pad_token: Union[str, AddedToken] = "<pad>",
+    ):
+        self.special_tokens = {
+            "pad": {"id": 0, "token": pad_token},
+            "eos": {"id": 1, "token": eos_token},
+            "unk": {"id": 2, "token": unk_token},
+        }
+
+        self.special_tokens_list = [None] * len(self.special_tokens)
+        for token_dict in self.special_tokens.values():
+            self.special_tokens_list[token_dict["id"]] = token_dict["token"]
+
+        tokenizer = Tokenizer(Unigram())
+
+        tokenizer.normalizer = normalizers.Sequence(
+            [
+                normalizers.Nmt(),
+                normalizers.NFKC(),
+                normalizers.Replace(Regex(" {2,}"), " "),
+                normalizers.Lowercase(),
+            ]
+        )
+        tokenizer.pre_tokenizer = pre_tokenizers.Sequence(
+            [
+                pre_tokenizers.Metaspace(replacement=replacement, add_prefix_space=add_prefix_space),
+                pre_tokenizers.Digits(individual_digits=True),
+                pre_tokenizers.Punctuation(),
+            ]
+        )
+        tokenizer.decoder = decoders.Metaspace(replacement=replacement, add_prefix_space=add_prefix_space)
+
+        tokenizer.post_processor = TemplateProcessing(
+            single=f"$A {self.special_tokens['eos']['token']}",
+            special_tokens=[(self.special_tokens["eos"]["token"], self.special_tokens["eos"]["id"])],
+        )
+
+        parameters = {
+            "model": "SentencePieceUnigram",
+            "replacement": replacement,
+            "add_prefix_space": add_prefix_space,
+        }
+
+        super().__init__(tokenizer, parameters)
+
+    def train(
+        self,
+        files: Union[str, List[str]],
+        vocab_size: int = 8000,
+        show_progress: bool = True,
+    ):
+        """Train the model using the given files"""
+
+        trainer = trainers.UnigramTrainer(
+            vocab_size=vocab_size,
+            special_tokens=self.special_tokens_list,
+            show_progress=show_progress,
+        )
+
+        if isinstance(files, str):
+            files = [files]
+        self._tokenizer.train(files, trainer=trainer)
+
+        self.add_unk_id()
+
+    def train_from_iterator(
+        self,
+        iterator: Union[Iterator[str], Iterator[Iterator[str]]],
+        vocab_size: int = 8000,
+        show_progress: bool = True,
+    ):
+        """Train the model using the given iterator"""
+
+        trainer = trainers.UnigramTrainer(
+            vocab_size=vocab_size,
+            special_tokens=self.special_tokens_list,
+            show_progress=show_progress,
+        )
+
+        self._tokenizer.train_from_iterator(iterator, trainer=trainer)
+
+        self.add_unk_id()
+
+    def add_unk_id(self):
+        tokenizer_json = json.loads(self._tokenizer.to_str())
+
+        tokenizer_json["model"]["unk_id"] = self.special_tokens["unk"]["id"]
+
+        self._tokenizer = Tokenizer.from_str(json.dumps(tokenizer_json))