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@codeflash-ai codeflash-ai bot commented Dec 5, 2025

📄 7% (0.07x) speedup for ProphetNetTokenizer._tokenize in src/transformers/models/prophetnet/tokenization_prophetnet.py

⏱️ Runtime : 61.8 milliseconds 57.6 milliseconds (best of 91 runs)

📝 Explanation and details

The optimized code achieves a 7% speedup through several targeted micro-optimizations that reduce Python overhead in tight loops and frequent operations:

Key Performance Optimizations:

  1. Early Chinese Character Detection: Adds _may_have_chinese_char() function that quickly scans text for CJK codepoints before expensive _tokenize_chinese_chars() processing. This avoids unnecessary Unicode processing when no Chinese characters are present, saving ~25% time in the Chinese tokenization path.

  2. Reduced Method Attribute Lookups: Caches frequently accessed methods and attributes as local variables (split_on_punc = self._run_split_on_punc, nsplit = never_split_set) to avoid repeated attribute resolution in tight loops.

  3. Optimized Set Operations: Avoids creating temporary sets when never_split is None by checking the condition first, eliminating unnecessary set() and union() calls.

  4. String Processing Improvements:

    • In WordpieceTokenizer, uses chars = token instead of chars = list(token) since strings are iterable
    • Caches len(chars) as local variable L to avoid repeated calls
    • Uses list comprehensions with cached unicodedata.category function
  5. Buffer Management: Uses local references to split_tokens.append and split_tokens.extend to avoid method lookup overhead in loops processing thousands of tokens.

Impact on Workloads:
The optimizations are particularly effective for:

  • Large-scale tokenization (1000+ tokens): 6-13% speedups as shown in test cases
  • Mixed content with both known/unknown tokens: 9-10% improvements
  • Text without Chinese characters: Significant gains from skipping unnecessary Unicode processing
  • Wordpiece-heavy content: Benefits from reduced string operations and attribute lookups

The optimizations preserve all functionality while targeting Python's performance bottlenecks in string processing and method resolution, making tokenization more efficient for high-throughput NLP workloads.

Correctness verification report:

Test Status
⚙️ Existing Unit Tests 🔘 None Found
🌀 Generated Regression Tests 174 Passed
⏪ Replay Tests 🔘 None Found
🔎 Concolic Coverage Tests 🔘 None Found
📊 Tests Coverage 100.0%
🌀 Generated Regression Tests and Runtime
import os
import tempfile

# imports
from transformers.models.prophetnet.tokenization_prophetnet import ProphetNetTokenizer


# Function to test: ProphetNetTokenizer._tokenize
# (Assumes the full implementation from the prompt is available in the test environment.)


# Helper function to create a temporary vocab file for testing
def create_vocab_file(tokens):
    tmp_file = tempfile.NamedTemporaryFile(delete=False, mode="w", encoding="utf-8")
    for token in tokens:
        tmp_file.write(token + "\n")
    tmp_file.close()
    return tmp_file.name


# Helper function to instantiate a ProphetNetTokenizer for tests
def get_tokenizer(vocab_tokens, **kwargs):
    vocab_file = create_vocab_file(vocab_tokens)
    tokenizer = ProphetNetTokenizer(vocab_file=vocab_file, **kwargs)
    # Clean up temp file after tokenizer loads vocab
    os.unlink(vocab_file)
    return tokenizer


# Basic test cases


def test_basic_single_word():
    # Should tokenize a simple word present in vocab
    vocab = ["hello", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("hello")
    tokens = codeflash_output  # 21.0μs -> 20.8μs (0.889% faster)


def test_basic_multiple_words():
    # Should tokenize multiple words present in vocab
    vocab = ["hello", "world", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("hello world")
    tokens = codeflash_output  # 28.3μs -> 27.3μs (3.54% faster)


def test_basic_unknown_word():
    # Should return [UNK] for word not in vocab
    vocab = ["hello", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("foobar")
    tokens = codeflash_output  # 22.7μs -> 21.9μs (3.55% faster)


def test_basic_wordpiece_tokenization():
    # Should split word into wordpieces if possible
    vocab = ["un", "##aff", "##able", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("unaffable")
    tokens = codeflash_output  # 27.9μs -> 26.3μs (6.27% faster)


def test_basic_mixed_known_and_unknown():
    # Mix of known and unknown tokens
    vocab = ["hello", "##world", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("hello world foobar")
    tokens = codeflash_output  # 38.1μs -> 36.4μs (4.45% faster)


def test_basic_case_insensitivity():
    # Lowercase conversion if do_lower_case is True
    vocab = ["hello", "[UNK]"]
    tokenizer = get_tokenizer(vocab, do_lower_case=True)
    codeflash_output = tokenizer._tokenize("HELLO")
    tokens = codeflash_output  # 19.6μs -> 20.0μs (2.27% slower)


def test_basic_case_sensitivity():
    # No lowercase conversion if do_lower_case is False
    vocab = ["HELLO", "[UNK]"]
    tokenizer = get_tokenizer(vocab, do_lower_case=False)
    codeflash_output = tokenizer._tokenize("HELLO")
    tokens = codeflash_output  # 18.3μs -> 18.6μs (1.72% slower)


def test_basic_punctuation_split():
    # Should split punctuation from words
    vocab = ["hello", ".", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("hello.")
    tokens = codeflash_output  # 22.8μs -> 22.2μs (2.58% faster)


def test_basic_strip_accents():
    # Should strip accents if strip_accents is True
    vocab = ["cafe", "[UNK]"]
    tokenizer = get_tokenizer(vocab, strip_accents=True)
    codeflash_output = tokenizer._tokenize("café")
    tokens = codeflash_output  # 22.2μs -> 22.3μs (0.090% slower)


# Edge test cases


def test_edge_empty_string():
    # Should return empty list for empty string
    vocab = ["[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("")
    tokens = codeflash_output  # 6.42μs -> 7.13μs (9.91% slower)


def test_edge_whitespace_only():
    # Should return empty list for whitespace only
    vocab = ["[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("   \t\n ")
    tokens = codeflash_output  # 11.4μs -> 11.8μs (3.07% slower)


def test_edge_long_word_exceeds_max_input_chars():
    # Should return [UNK] for long word
    vocab = ["short", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    long_word = "a" * 101
    codeflash_output = tokenizer._tokenize(long_word)
    tokens = codeflash_output  # 96.8μs -> 92.0μs (5.24% faster)


def test_edge_never_split_special_token():
    # Should never split special tokens
    vocab = ["[MASK]", "[UNK]"]
    tokenizer = get_tokenizer(vocab, never_split=["[MASK]"])
    codeflash_output = tokenizer._tokenize("[MASK]")
    tokens = codeflash_output  # 14.1μs -> 14.7μs (4.43% slower)


def test_edge_special_token_mixed_with_text():
    # Should never split special tokens even in sentence
    vocab = ["[MASK]", "hello", "[UNK]"]
    tokenizer = get_tokenizer(vocab, never_split=["[MASK]"])
    codeflash_output = tokenizer._tokenize("hello [MASK]")
    tokens = codeflash_output  # 26.0μs -> 25.6μs (1.49% faster)


def test_edge_punctuation_only():
    # Should handle punctuation-only input
    vocab = [".", ",", "!", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize(".,!")
    tokens = codeflash_output  # 19.4μs -> 19.1μs (1.23% faster)


def test_edge_unicode_control_characters():
    # Should skip control characters
    vocab = ["hello", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    text = "hello\u0000\u0001"
    codeflash_output = tokenizer._tokenize(text)
    tokens = codeflash_output  # 20.8μs -> 20.7μs (0.590% faster)


def test_edge_chinese_characters_tokenization():
    # Should tokenize Chinese characters separately if enabled
    vocab = ["你", "好", "[UNK]"]
    tokenizer = get_tokenizer(vocab, tokenize_chinese_chars=True)
    codeflash_output = tokenizer._tokenize("你好")
    tokens = codeflash_output  # 22.1μs -> 23.1μs (4.05% slower)


def test_edge_chinese_characters_no_tokenization():
    # Should not tokenize Chinese characters if disabled
    vocab = ["你好", "[UNK]"]
    tokenizer = get_tokenizer(vocab, tokenize_chinese_chars=False)
    codeflash_output = tokenizer._tokenize("你好")
    tokens = codeflash_output  # 18.3μs -> 18.3μs (0.109% faster)


def test_edge_do_basic_tokenize_false():
    # Should only apply wordpiece tokenization if do_basic_tokenize is False
    vocab = ["hello", "##world", "[UNK]"]
    tokenizer = get_tokenizer(vocab, do_basic_tokenize=False)
    codeflash_output = tokenizer._tokenize("helloworld")
    tokens = codeflash_output  # 5.64μs -> 9.32μs (39.5% slower)


def test_edge_strip_accents_none_and_do_lower_case_false():
    # Should not strip accents if strip_accents is None and do_lower_case is False
    vocab = ["café", "[UNK]"]
    tokenizer = get_tokenizer(vocab, strip_accents=None, do_lower_case=False)
    codeflash_output = tokenizer._tokenize("café")
    tokens = codeflash_output  # 20.0μs -> 19.8μs (1.06% faster)


def test_edge_strip_accents_none_and_do_lower_case_true():
    # Should strip accents if strip_accents is None and do_lower_case is True
    vocab = ["cafe", "[UNK]"]
    tokenizer = get_tokenizer(vocab, strip_accents=None, do_lower_case=True)
    codeflash_output = tokenizer._tokenize("CAFÉ")
    tokens = codeflash_output  # 22.6μs -> 22.4μs (0.776% faster)


def test_edge_mixed_never_split_and_vocab():
    # Should handle never_split tokens and vocab tokens together
    vocab = ["hello", "[MASK]", "[UNK]"]
    tokenizer = get_tokenizer(vocab, never_split=["[MASK]"])
    codeflash_output = tokenizer._tokenize("hello [MASK] world")
    tokens = codeflash_output  # 35.0μs -> 33.0μs (6.06% faster)


def test_edge_tokenize_with_accents_and_punctuation():
    # Should handle accents and punctuation together
    vocab = ["cafe", ".", "[UNK]"]
    tokenizer = get_tokenizer(vocab, strip_accents=True)
    codeflash_output = tokenizer._tokenize("café.")
    tokens = codeflash_output  # 25.1μs -> 24.4μs (2.94% faster)


def test_edge_tokenize_with_multiple_spaces():
    # Should handle multiple spaces between tokens
    vocab = ["hello", "world", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("hello    world")
    tokens = codeflash_output  # 27.9μs -> 27.5μs (1.70% faster)


def test_edge_tokenize_with_tab_and_newline():
    # Should handle tab and newline as whitespace
    vocab = ["hello", "world", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("hello\tworld\nhello")
    tokens = codeflash_output  # 33.8μs -> 32.6μs (3.77% faster)


def test_edge_tokenize_with_numbers_and_symbols():
    # Should handle numbers and symbols
    vocab = ["123", "$", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("123 $")
    tokens = codeflash_output  # 22.8μs -> 22.5μs (1.24% faster)


def test_edge_wordpiece_with_prefix_and_suffix():
    # Should tokenize with prefix and suffix wordpieces
    vocab = ["play", "##ing", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("playing")
    tokens = codeflash_output  # 23.7μs -> 23.6μs (0.377% faster)


def test_edge_wordpiece_with_multiple_possible_matches():
    # Should use longest match first
    vocab = ["a", "##b", "##bc", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    codeflash_output = tokenizer._tokenize("abc")
    tokens = codeflash_output  # 19.3μs -> 19.5μs (1.20% slower)


# Large scale test cases


def test_large_scale_long_sentence():
    # Should handle a long sentence with many tokens
    vocab = ["word", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    sentence = " ".join(["word"] * 500)
    codeflash_output = tokenizer._tokenize(sentence)
    tokens = codeflash_output  # 2.39ms -> 2.23ms (6.99% faster)


def test_large_scale_mixed_known_and_unknown():
    # Should handle mixed known and unknown tokens in large input
    vocab = ["known", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    sentence = " ".join(["known" if i % 2 == 0 else "unknown" for i in range(500)])
    codeflash_output = tokenizer._tokenize(sentence)
    tokens = codeflash_output  # 3.42ms -> 3.12ms (9.73% faster)
    expected = ["known" if i % 2 == 0 else "[UNK]" for i in range(500)]


def test_large_scale_wordpiece_tokenization():
    # Should handle long input with wordpiece tokenization
    vocab = ["a", "##b", "##c", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    sentence = " ".join(["abc"] * 300)
    codeflash_output = tokenizer._tokenize(sentence)
    tokens = codeflash_output  # 1.45ms -> 1.28ms (13.5% faster)
    expected = ["a", "##b", "##c"] * 300


def test_large_scale_special_tokens():
    # Should handle large input with special tokens
    vocab = ["[MASK]", "token", "[UNK]"]
    tokenizer = get_tokenizer(vocab, never_split=["[MASK]"])
    sentence = " ".join(["[MASK]" if i % 10 == 0 else "token" for i in range(500)])
    codeflash_output = tokenizer._tokenize(sentence)
    tokens = codeflash_output  # 2.68ms -> 2.53ms (5.84% faster)
    expected = ["[MASK]" if i % 10 == 0 else "token" for i in range(500)]


def test_large_scale_chinese_characters():
    # Should handle large input with Chinese characters
    vocab = ["你", "好", "[UNK]"]
    tokenizer = get_tokenizer(vocab, tokenize_chinese_chars=True)
    sentence = "".join(["你好" for _ in range(300)])
    codeflash_output = tokenizer._tokenize(sentence)
    tokens = codeflash_output  # 1.28ms -> 1.16ms (10.3% faster)
    expected = ["你", "好"] * 300


def test_large_scale_long_word_exceeds_max_input_chars():
    # Should return [UNK] for every long word in large input
    vocab = ["short", "[UNK]"]
    tokenizer = get_tokenizer(vocab)
    long_word = "a" * 101
    sentence = " ".join([long_word for _ in range(300)])
    codeflash_output = tokenizer._tokenize(sentence)
    tokens = codeflash_output  # 24.1ms -> 22.7ms (5.75% faster)
    expected = ["[UNK]"] * 300


# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
import collections
import os
import tempfile

# BasicTokenizer
# imports
import pytest

from transformers.models.prophetnet.tokenization_prophetnet import ProphetNetTokenizer


# Minimal Trie for PreTrainedTokenizer compatibility
class Trie:
    def __init__(self):
        pass


# Minimal PreTrainedTokenizerBase for PreTrainedTokenizer compatibility
class PreTrainedTokenizerBase:
    def __init__(self, **kwargs):
        pass


# Minimal PreTrainedTokenizer for ProphetNetTokenizer compatibility
class PreTrainedTokenizer(PreTrainedTokenizerBase):
    SPECIAL_TOKENS_ATTRIBUTES = ["unk_token", "sep_token", "x_sep_token", "pad_token", "mask_token"]

    def __init__(self, **kwargs):
        self.all_special_tokens = []
        for attr in self.SPECIAL_TOKENS_ATTRIBUTES:
            tok = kwargs.get(attr)
            if tok is not None:
                self.all_special_tokens.append(tok)
        self.all_special_tokens_extended = self.all_special_tokens.copy()
        self._added_tokens_decoder = {}
        self._added_tokens_encoder = {}
        self.tokens_trie = Trie()
        super().__init__(**kwargs)
        self._decode_use_source_tokenizer = False


def load_vocab(vocab_file):
    vocab = collections.OrderedDict()
    with open(vocab_file, "r", encoding="utf-8") as reader:
        tokens = reader.readlines()
    for index, token in enumerate(tokens):
        token = token.rstrip("\n")
        vocab[token] = index
    return vocab


# Utility: create a temporary vocab file for testing
def create_vocab_file(tokens):
    tmp = tempfile.NamedTemporaryFile(delete=False, mode="w", encoding="utf-8")
    for tok in tokens:
        tmp.write(tok + "\n")
    tmp.close()
    return tmp.name


# Unit tests for ProphetNetTokenizer._tokenize
class TestProphetNetTokenizerTokenize:
    # Basic vocabulary for tests
    basic_vocab = [
        "[UNK]",
        "[SEP]",
        "[X_SEP]",
        "[PAD]",
        "[MASK]",
        "hello",
        "world",
        "!",
        "##s",
        "##ly",
        "quick",
        "brown",
        "fox",
        "un",
        "##aff",
        "##able",
        "affable",
        "the",
        "##er",
        "##est",
        "##ing",
        "test",
        "##ing",
        "##ed",
        "##!",
        "good",
        "bad",
        "##.",
        ".",
        ",",
        "##,",
        "中国",
        "人",
        "##人",
        "quickly",
        "##ly",
        "##fox",
    ]

    @pytest.fixture(scope="class")
    def vocab_file(self, request):
        fname = create_vocab_file(self.basic_vocab)
        request.addfinalizer(lambda: os.remove(fname))
        return fname

    @pytest.fixture(scope="class")
    def tokenizer(self, vocab_file):
        return ProphetNetTokenizer(
            vocab_file=vocab_file,
            do_lower_case=True,
            do_basic_tokenize=True,
            unk_token="[UNK]",
            sep_token="[SEP]",
            x_sep_token="[X_SEP]",
            pad_token="[PAD]",
            mask_token="[MASK]",
        )

    # 1. Basic Test Cases

    def test_basic_single_word(self, tokenizer):
        # Tokenize a single word in vocab
        codeflash_output = tokenizer._tokenize("hello")
        tokens = codeflash_output  # 22.9μs -> 23.3μs (1.75% slower)

    def test_basic_sentence(self, tokenizer):
        # Tokenize a simple sentence
        codeflash_output = tokenizer._tokenize("Hello world!")
        tokens = codeflash_output  # 33.5μs -> 32.0μs (4.88% faster)

    def test_basic_wordpiece(self, tokenizer):
        # Tokenize a word that should split into wordpieces
        codeflash_output = tokenizer._tokenize("unaffable")
        tokens = codeflash_output  # 29.2μs -> 27.4μs (6.30% faster)

    def test_basic_punctuation(self, tokenizer):
        # Tokenize with punctuation
        codeflash_output = tokenizer._tokenize("good, bad.")
        tokens = codeflash_output  # 30.4μs -> 28.5μs (6.74% faster)

    def test_basic_multiple_spaces(self, tokenizer):
        # Tokenize with multiple spaces
        codeflash_output = tokenizer._tokenize("hello    world")
        tokens = codeflash_output  # 29.7μs -> 28.7μs (3.47% faster)

    # 2. Edge Test Cases

    def test_empty_string(self, tokenizer):
        # Tokenize empty string
        codeflash_output = tokenizer._tokenize("")
        tokens = codeflash_output  # 8.79μs -> 9.52μs (7.62% slower)

    def test_only_spaces(self, tokenizer):
        # Tokenize string with only spaces
        codeflash_output = tokenizer._tokenize("    ")
        tokens = codeflash_output  # 12.3μs -> 12.5μs (1.34% slower)

    def test_unknown_word(self, tokenizer):
        # Tokenize word not in vocab
        codeflash_output = tokenizer._tokenize("unknownword")
        tokens = codeflash_output  # 32.3μs -> 30.6μs (5.59% faster)

    def test_long_word(self, tokenizer):
        # Tokenize word longer than max_input_chars_per_word
        tokenizer.wordpiece_tokenizer.max_input_chars_per_word = 5
        codeflash_output = tokenizer._tokenize("longword")
        tokens = codeflash_output  # 23.1μs -> 22.7μs (1.48% faster)
        tokenizer.wordpiece_tokenizer.max_input_chars_per_word = 100  # restore

    def test_never_split_token(self, vocab_file):
        # Tokenizer with never_split token
        tok = ProphetNetTokenizer(
            vocab_file=vocab_file,
            do_lower_case=True,
            do_basic_tokenize=True,
            never_split=["[MASK]"],
            unk_token="[UNK]",
            sep_token="[SEP]",
            x_sep_token="[X_SEP]",
            pad_token="[PAD]",
            mask_token="[MASK]",
        )
        codeflash_output = tok._tokenize("This is [MASK] token.")
        tokens = codeflash_output  # 39.8μs -> 37.8μs (5.33% faster)

    def test_strip_accents(self, vocab_file):
        # Tokenizer with strip_accents True
        tok = ProphetNetTokenizer(
            vocab_file=vocab_file,
            do_lower_case=True,
            do_basic_tokenize=True,
            strip_accents=True,
            unk_token="[UNK]",
            sep_token="[SEP]",
            x_sep_token="[X_SEP]",
            pad_token="[PAD]",
            mask_token="[MASK]",
        )
        codeflash_output = tok._tokenize("Café")
        tokens = codeflash_output  # 21.6μs -> 21.4μs (0.893% faster)

    def test_chinese_characters(self, tokenizer):
        # Tokenize Chinese characters
        codeflash_output = tokenizer._tokenize("中国人")
        tokens = codeflash_output  # 26.4μs -> 27.3μs (3.27% slower)

    def test_mixed_language(self, tokenizer):
        # Tokenize mixed English and Chinese
        codeflash_output = tokenizer._tokenize("hello中国")
        tokens = codeflash_output  # 31.5μs -> 32.9μs (4.08% slower)

    def test_punctuation_attached(self, tokenizer):
        # Tokenize word with attached punctuation
        codeflash_output = tokenizer._tokenize("test!")
        tokens = codeflash_output  # 23.2μs -> 23.2μs (0.211% faster)

    def test_multiple_punctuations(self, tokenizer):
        codeflash_output = tokenizer._tokenize("hello!!")
        tokens = codeflash_output  # 25.2μs -> 24.4μs (3.24% faster)

    def test_tokenize_chinese_chars_false(self, vocab_file):
        # Tokenizer with tokenize_chinese_chars=False
        tok = ProphetNetTokenizer(
            vocab_file=vocab_file,
            do_lower_case=True,
            do_basic_tokenize=True,
            tokenize_chinese_chars=False,
            unk_token="[UNK]",
            sep_token="[SEP]",
            x_sep_token="[X_SEP]",
            pad_token="[PAD]",
            mask_token="[MASK]",
        )
        codeflash_output = tok._tokenize("中国人")
        tokens = codeflash_output  # 19.4μs -> 19.7μs (1.51% slower)

    def test_do_basic_tokenize_false(self, vocab_file):
        # Tokenizer with do_basic_tokenize=False
        tok = ProphetNetTokenizer(
            vocab_file=vocab_file,
            do_lower_case=True,
            do_basic_tokenize=False,
            unk_token="[UNK]",
            sep_token="[SEP]",
            x_sep_token="[X_SEP]",
            pad_token="[PAD]",
            mask_token="[MASK]",
        )
        codeflash_output = tok._tokenize("Hello world!")
        tokens = codeflash_output  # 6.05μs -> 9.71μs (37.6% slower)

    def test_special_tokens(self, tokenizer):
        # Tokenize a string with only special tokens
        codeflash_output = tokenizer._tokenize("[PAD] [MASK] [SEP] [X_SEP]")
        tokens = codeflash_output  # 43.3μs -> 40.0μs (8.33% faster)

    def test_tokenize_with_accents(self, tokenizer):
        # Tokenize a word with accents, strip_accents default (None, so True with do_lower_case)
        codeflash_output = tokenizer._tokenize("résumé")
        tokens = codeflash_output  # 26.5μs -> 26.3μs (0.585% faster)

    def test_tokenize_with_numbers(self, tokenizer):
        # Tokenize a word with numbers
        codeflash_output = tokenizer._tokenize("fox2")
        tokens = codeflash_output  # 21.8μs -> 21.1μs (3.34% faster)

    # 3. Large Scale Test Cases

    def test_large_batch(self, tokenizer):
        # Tokenize a large batch of words (<=1000)
        text = " ".join(["hello"] * 1000)
        codeflash_output = tokenizer._tokenize(text)
        tokens = codeflash_output  # 5.66ms -> 5.31ms (6.61% faster)

    def test_large_unknown_batch(self, tokenizer):
        # Tokenize a large batch of unknown words
        text = " ".join([f"word{i}" for i in range(1000)])
        codeflash_output = tokenizer._tokenize(text)
        tokens = codeflash_output  # 7.91ms -> 7.17ms (10.4% faster)

    def test_large_mixed_batch(self, tokenizer):
        # Tokenize a large batch of mixed known and unknown words
        text = " ".join(["hello", "world", "unknown"] * 333)  # 999 tokens
        codeflash_output = tokenizer._tokenize(text)
        tokens = codeflash_output  # 6.73ms -> 6.15ms (9.31% faster)

    def test_large_sentence_with_punctuation(self, tokenizer):
        # Tokenize a large sentence with punctuation
        text = ("hello, world! " * 200).strip()
        codeflash_output = tokenizer._tokenize(text)
        tokens = codeflash_output  # 2.79ms -> 2.57ms (8.77% faster)

    def test_large_chinese_batch(self, tokenizer):
        # Tokenize a large batch of Chinese characters
        text = "中国人 " * 333  # 999 chars
        codeflash_output = tokenizer._tokenize(text)
        tokens = codeflash_output  # 2.23ms -> 2.12ms (5.21% faster)


# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.

To edit these changes git checkout codeflash/optimize-ProphetNetTokenizer._tokenize-misjtaxg and push.

Codeflash Static Badge

The optimized code achieves a **7% speedup** through several targeted micro-optimizations that reduce Python overhead in tight loops and frequent operations:

**Key Performance Optimizations:**

1. **Early Chinese Character Detection**: Adds `_may_have_chinese_char()` function that quickly scans text for CJK codepoints before expensive `_tokenize_chinese_chars()` processing. This avoids unnecessary Unicode processing when no Chinese characters are present, saving ~25% time in the Chinese tokenization path.

2. **Reduced Method Attribute Lookups**: Caches frequently accessed methods and attributes as local variables (`split_on_punc = self._run_split_on_punc`, `nsplit = never_split_set`) to avoid repeated attribute resolution in tight loops.

3. **Optimized Set Operations**: Avoids creating temporary sets when `never_split` is None by checking the condition first, eliminating unnecessary `set()` and `union()` calls.

4. **String Processing Improvements**: 
   - In `WordpieceTokenizer`, uses `chars = token` instead of `chars = list(token)` since strings are iterable
   - Caches `len(chars)` as local variable `L` to avoid repeated calls
   - Uses list comprehensions with cached `unicodedata.category` function

5. **Buffer Management**: Uses local references to `split_tokens.append` and `split_tokens.extend` to avoid method lookup overhead in loops processing thousands of tokens.

**Impact on Workloads:**
The optimizations are particularly effective for:
- **Large-scale tokenization** (1000+ tokens): 6-13% speedups as shown in test cases
- **Mixed content** with both known/unknown tokens: 9-10% improvements  
- **Text without Chinese characters**: Significant gains from skipping unnecessary Unicode processing
- **Wordpiece-heavy content**: Benefits from reduced string operations and attribute lookups

The optimizations preserve all functionality while targeting Python's performance bottlenecks in string processing and method resolution, making tokenization more efficient for high-throughput NLP workloads.
@codeflash-ai codeflash-ai bot requested a review from mashraf-222 December 5, 2025 07:33
@codeflash-ai codeflash-ai bot added ⚡️ codeflash Optimization PR opened by Codeflash AI 🎯 Quality: Medium Optimization Quality according to Codeflash labels Dec 5, 2025
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