Behind the Curtain: The Rise of GPT

Prateek Bisht
5 min readJul 7, 2024

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GPT: The Magic of Generative Pretrained Transformers ๐Ÿง โœจ

GPT, or Generative Pretrained Transformer, is a revolutionary neural network core invention that has transformed many modern AI applications.

How Transformers Work ๐Ÿš€

  • Voice to Text ๐ŸŽคโžก๏ธ๐Ÿ“
  • Text to Voice ๐Ÿ“โžก๏ธ๐ŸŽง
  • Text to Image ๐Ÿ“โžก๏ธ๐Ÿ–ผ๏ธ

Originally, Google used transformers in 2017 for translating text to different languages. But GPT has evolved significantly since then.

The Evolution of GPT ๐ŸŒŸ

  • GPT-2: It generates text by predicting things randomly to complete sentences.
  • GPT-3: Creates coherent and sensible stories. Inputs are broken into pieces called tokens (associated with vectors), which pass through attention blocks that communicate and share information with each other.

Attention and Perceptron ๐Ÿ“Šโžก๏ธ๐Ÿง 

Attention in GPT passes through a multilayer perceptron, a complex process involving giant matrix multiplications. The final matrix operation gives a word distribution, starting from a given prompt.

Machine Learning (ML) vs. Deep Learning (DL) ๐Ÿค–

  • ML: Learns from data inputs using intuition and pattern recognition. Early AI models like linear regression find the best fit for data. Now, tunable parameters train models to shape the output.
  • DL: Uses backpropagation to refine weights (tunable parameters). Input data is formatted in arrays called tensors, transforming through multiple layers to the output. GPT-3, for example, has 175 billion weights organized into 27,938 layers. Most computations involve matrix multiplications, with weights acting as the brain during training.

The Power of Words and Embeddings ๐Ÿ“š๐Ÿ”—

GPT has a vocabulary of 50,000 words, each entered into an embedding matrix. During training, the model tweaks and tunes words, linking similar ones (e.g., king and queen, man and woman). For instance, you can find โ€œqueenโ€ by computing โ€œking + woman โ€” manโ€.

Image Associations ๐Ÿ–ผ๏ธ

Like words, images can be associated in meaningful ways. For example, โ€œcatsโ€ and โ€œcatโ€ are recognized as plurals. GPT links words to form sentences, often using probabilities and softmax functions to predict the next word.

Example: Harry Potter ๐Ÿง™โ€โ™‚๏ธ๐Ÿ“–

GPT can generate text about โ€œHarry Potterโ€ by understanding the context and using a probability matrix for the last word in a sentence. This process repeats iteratively, refining the text output.

Key Moments ๐ŸŒŸ

The Transformer model focuses on attention mechanisms to process data, gradually adjusting embeddings to capture contextual meaning. This involves updating embeddings to convey rich contextual semantics, enhancing language understanding and prediction accuracy.

  • Importance of Attention Mechanisms: Crucial for language processing and AI advancements. ๐ŸŒ๐Ÿš€
  • Token to Embedding Linking: Transformers link tokens to high-dimensional vectors (embeddings) to encode contextual semantics. ๐Ÿ”—โœจ
  • Attention Block Refinement: Attention blocks refine embeddings to convey nuanced meanings, improving language context comprehension. ๐Ÿง ๐Ÿ’ก

The concept of attention mechanisms in deep learning models uses query, key, and value vectors to calculate relevance scores for words. This helps focus on relevant information and improve training efficiency.

  • Query Vectors: Computed by multiplying embedding vectors with a query matrix, enhancing model parameter learning from data. ๐Ÿ”๐Ÿ”ข
  • Key Vectors: Created by multiplying embedding vectors with a key matrix, mapping concepts like โ€˜fluffyโ€™ and โ€˜blueโ€™ to related query vectors, aiding in relevance computation. ๐Ÿ”‘๐Ÿ“˜
  • Importance of Masking: Prevents future tokens from influencing previous ones, ensuring effective training by accurately predicting subsequent tokens without interference. ๐Ÿšซ๐Ÿ”ฎ

Attention mechanisms in natural language processing use embedding matrices and value vectors to enhance contextual understanding. Balancing parameters for value mapping is essential for effective attention models.

  • Embedding Matrices and Value Vectors: Crucial for expanding contextual understanding in language models. ๐Ÿ—‚๏ธ๐Ÿ’ฌ
  • Balancing Parameters: Essential for effective attention mechanisms in NLP tasks. โš–๏ธ๐Ÿ“ˆ
  • Cross-Attention Mechanisms: Involving keys and queries from different languages, improving translation accuracy in multilingual models. ๐ŸŒ๐Ÿ”ค

Transformer models with multiple attention heads highlight the importance of multiple context updates in understanding word meanings. Parallel operations in different heads allow for a deeper understanding of diverse contexts.

  • Multiple Attention Heads: Transformer models use multiple attention heads to process different contexts, impacting the meaning of words. ๐Ÿ”„๐Ÿ” 
  • Parallel Processing Design: Enables capturing various interpretations of context, enhancing contextual understanding and semantic encoding. ๐Ÿงฉ๐Ÿ’ป
  • Scalability and Efficiency: Transformer modelsโ€™ focus on parallelization contributes to significant improvements in performance and quality, offering advantages in deep learning architectures. ๐Ÿ“Šโš™๏ธ

Insights ๐Ÿ’ก

  • Attention Mechanisms: Essential for the contextual updating of word embeddings, enabling rich contextual meaning in language models. ๐Ÿ”‘๐Ÿ“
  • Parallel Processing: Multi-headed attention facilitates the parallel processing of contextual information, enhancing the modelโ€™s capacity to learn and encode complex relationships within the text. ๐ŸŒ๐Ÿง 
  • Efficient Computation: The parallelizable nature of the attention mechanism is crucial for the success of transformers, allowing for efficient computation of a large number of parameters and significant performance improvements. โš™๏ธ๐Ÿ’ป
  • Model Complexity: The substantial number of parameters in attention heads and layers highlights the complexity and scale of deep learning architectures like GPT-3. ๐Ÿ”ข๐Ÿง 
  • Optimized Value Matrices: Factoring value matrices into value down and value up matrices optimizes computational efficiency in the attention mechanism. โ†”๏ธ๐Ÿ“ˆ
  • Understanding Transformers: Grasping the functionality and design of attention heads is essential for understanding the inner workings of transformers and their application in various AI tasks. ๐Ÿ”๐Ÿค–
  • Fundamental Building Block: The attention mechanism serves as a fundamental building block in modern language models, paving the way for advancements in natural language processing and AI technologies. ๐Ÿ—๏ธ๐Ÿ’ฌ

Summary ๐ŸŒŸ

GPT and transformers have revolutionized AI with their ability to transform text, voice, and images through advanced neural network techniques. Whether generating coherent stories or translating languages, their potential applications are vast and continually evolving. The attention mechanism is the core of the Transformer model, enabling it to capture contextual information and update word embeddings accordingly. By computing attention scores between each token and all other tokens, the model can selectively focus on relevant parts of the input when generating the next token. ๐Ÿš€๐Ÿง ๐Ÿ”

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