minbpe.🔥

This project is a port of Andrej Karpathy's minbpe to Mojo, currently in beta.

Minbpe implements the Byte Pair Encoding (BPE) algorithm, which is commonly used in large language models (LLMs) tokenization. For a comprehensive explanation of this project, visit its GitHub page at https://github.com/karpathy/minbpe.

Not all features of minpe are available yet, but will be introduced as the project evolves. Currently, the main focus is on enhancing the performance of the core functionality.

Implementation

Due to differences in language capabilities, the architecture of this port has been modified to fit the constraints and features of Mojo. While the architecture is different, the core functionalities and behaviors of the application remain the same as in the original. As Mojo's language features continue to evolve, we expect to further refine and redesign the project.

Available Tokenizer

Tokenizers in minbpe.mojo are implemented by confirming to the Tokenizer trait, which defines the required methods around tokenization processes.

• BasicTokenizer: Implements the BasicTokenizer, the simplest implementation of the BPE algorithm that runs directly on text.
• RegexTokenizer: Implements the RegexTokenizer that further splits the input text by a regex pattern, which is a preprocessing stage that splits up the input text by categories (think: letters, numbers, punctuation) before tokenization. This ensures that no merges will happen across category boundaries. This was introduced in the GPT-2 paper and continues to be in use as of GPT-4. This class also handles special tokens, if any.
• GPT4Tokenizer to be implemented

Quick Start

• First make sure you have Mojo 24.4 installed.
• In addtion you need to install the Python library regex. We rely on regex because Mojo currently lacks a powerful native regular expression library. Mojo's ability to utilize Python libraries allows us to enhance functionality in this way. For information on this powerful language feature, see the Python Integration section in the official Mojo documentation.

pip install regex

• The quick start example from minbpe can be implement with minbpe.mojo as follows:

from mojobpe import Tokenizer,BasicTokenizer
from mojobpe.utils.tat import print_list_int

fn main() raises:
   var text = "aaabdaaabac"

   var tokenizer = Tokenizer[BasicTokenizer]()
   tokenizer.train(text, 256 + 3) # 256 are the byte tokens, then do 3 merges
   print_list_int(tokenizer.encode(text))
   # [258, 100, 258, 97, 99]

   print(tokenizer.decode(List[Int](258, 100, 258, 97, 99)))
   # aaabdaaabac

   tokenizer.save("toy")
   # writes toy.model (for loading) 

Benchmarks

A detailed benchmark analysis will be available soon.

For now we have included a Mojo port of train.py from the original repository, which times the training of both the Basic and Regex Tokenizer with the text from Taylor Swift's Wikipedia page. In our preliminary tests, the Mojo version proves to be approximately three times faster than the original Python implementation. You can run this training benchmark test using the following command:

mojo train.mojo

Changelog

• 2024.06.07
  • Update to Mojo 24.4
  • Performance improvements thanks to new features of CompactDict
• 2024.05.14
  • Status: Beta
  • Performance improvements
• 2024.05.12
  • Switch to MoString for String concatenation
• 2024.05.04
  • Initial repository setup and commit.

Remarks

• We achieved a significant performance boost by utilizing Maxim Zaks' exceptional Mojo library, CompactDict, which provides blazing fast dictionary implementations. We've incorporated a slightly modified version of this library in the mojobe.utils folder (generic_dict and string_dict); all credits go to him.
• Gregor Purdy has implemented an impressive Rust port of minbpe. In our initial tests, Gregor's port performs similar to our current Mojo port..

License

MIT