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BERT and GPT Models

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Here’s a clear, well-organized breakdown of BERT and GPT Models β€” ideal for notes, presentations, or a quick concept refresh:

πŸ€– BERT vs. GPT Models in NLP

πŸ“Œ Overview

Both BERT and GPT are Transformer-based models that have transformed natural language processing β€” but they serve different purposes and use different architectures.

🧠 BERT (Bidirectional Encoder Representations from Transformers)

πŸ” What is BERT?

  • Developed by Google AI in 2018
  • Uses only the encoder part of the Transformer architecture
  • Trained to understand the context of a word in both directions (left and right)

πŸ—οΈ Architecture

  • Bidirectional attention: sees the whole sentence at once
  • Pre-trained on:
    • Masked Language Modeling (MLM): Randomly masks words and predicts them
    • Next Sentence Prediction (NSP): Predicts if one sentence follows another

πŸ”§ Use Cases

  • Text classification
  • Named entity recognition (NER)
  • Question answering (e.g., SQuAD)
  • Sentence similarity tasks

πŸ“Œ Notable Variants

Model Notes
RoBERTa Robustly optimized BERT (no NSP, more training data)
DistilBERT Smaller, faster version of BERT
ALBERT Lite BERT with shared parameters

🧠 GPT (Generative Pretrained Transformer)

πŸ” What is GPT?

  • Developed by OpenAI
  • Uses only the decoder part of the Transformer
  • Unidirectional: predicts the next word using only the previous words (left-to-right)

πŸ—οΈ Architecture

  • Trained with causal (autoregressive) language modeling: learns to predict the next word in a sequence
  • Fine-tuned for tasks like text generation, summarization, translation, etc.

πŸ”§ Use Cases

  • Text generation (stories, articles, code)
  • Chatbots (like ChatGPT)
  • Summarization and translation
  • Creative writing

πŸ“Œ Evolution

Model Highlights
GPT-1 Proof of concept
GPT-2 Generated coherent text, 1.5B parameters
GPT-3 175B parameters, few-shot learning
GPT-4 Multimodal, stronger reasoning and alignment
GPT-4 Turbo Faster, cheaper, used in ChatGPT

πŸ”„ Key Differences at a Glance

Feature BERT GPT
Architecture Encoder-only Decoder-only
Direction Bidirectional Unidirectional (left-to-right)
Primary Task Understanding Generation
Pretraining Masked words & next sentence Next word prediction
Strengths Classification, Q&A Writing, dialogue, creativity

πŸ§ͺ Real-World Applications

  • BERT: Search engines (Google), sentence analysis, medical text analysis
  • GPT: ChatGPT, content generation, language translation, coding assistants

Would you like a comparison diagram or a side-by-side code example using BERT and GPT?