Byte Pair Encoding

• Byte Pair Encoding (BPE):
  • A form of data compression technique originally developed for text.
  • Encodes a sequence of bytes and reduces redundancy by replacing the most frequently occurring pairs of bytes wi

th a single unused byte or symbol.

• Commonly used in natural language processing (NLP) to preprocess text data, especially for subword tokenization.

• Process:
  • Count all the pairs of contiguous symbols in the data.
  • Identify the most frequent pair and replace all occurrences of that pair with a new symbol.
  • Repeat the process for a predefined number of iterations or until a certain compression ratio is achieved.
• Applications:
  • Utilized in various NLP models, including transformers (like GPT) for efficiently handling large vocabularies by producing subword units.
  • Reduces out-of-vocabulary words by breaking rare words into smaller, common subword units.
• Advantages:
  • Efficient handling of large datasets with diverse vocabularies.
  • Balances between fully character-based and word-based encoding, improving efficiency and performance.
• Limitations:
  • May lead to the creation of subword units that are not meaningful in isolation.
  • Requires careful tuning of the number of merges to avoid overfitting to the training data.