Build a Small Language Model (SLM) From Scratch
Technology

Build a Small Language Model (SLM) From Scratch

2:48:02
May 31, 2025
Vizuara
Added by Anshul Sharma

What You'll Learn

  • Build a small language model from scratch using the Tiny Stories dataset.
  • Implement data preprocessing techniques like Byte Pair Encoding (BPE) for efficient tokenization.
  • Understand and implement the core components of a transformer-based language model, including attention mechanisms and training optimization strategies.
Video Breakdown
This video provides a comprehensive guide to building a small language model (SLM) from scratch using the Tiny Stories dataset. It covers the entire process, from data preprocessing and tokenization using Byte Pair Encoding (BPE) to defining the model architecture with token embeddings, attention mechanisms, and transformer blocks. The video also details the training pipeline, including loss function calculation, optimization techniques, and inference strategies, demonstrating the model's ability to generate coherent stories despite its small size and highlighting potential applications of SLMs.
Key Topics
Language Model Data Preprocessing Tokenization Model Architecture Attention Mechanism Transformer Block
Video Index
Introduction and Data Preparation
This module introduces the project of building a small language model and covers the essential steps...
This module introduces the project of building a small language model and covers the essential steps of data preparation, including dataset selection, tokenization, and creating training and validation data.
Project Overview and Dataset Introduction
0:00
Project Overview and Dataset Introduction
0:00 - 12:03
Introduces the project's goal of building a small language model using the Tiny Stories dataset and outlines the key steps involved.
Small Language Model Tiny Stories Dataset Project Goals
Tokenization and Data Storage
12:00
Tokenization and Data Storage
12:00 - 36:04
Explains the importance of tokenization, introduces Byte Pair Encoding (BPE), and describes how to store token IDs in .bin files for efficient training.
Tokenization Byte Pair Encoding .Bin File Storage GPT2 Tokenizer
Creating Training and Validation Data
36:02
Creating Training and Validation Data
36:02 - 48:04
Details the process of converting text data into numerical format using tokenization and creating input-output pairs for language model training.
Train.Bin Validation.Bin Token Ids Next Token Prediction
Model Architecture: Embeddings and Attention
This module focuses on defining the architecture of the language model, including token embeddings, ...
This module focuses on defining the architecture of the language model, including token embeddings, layer normalization, multi-head attention, and the attention mechanism.
Input/Output Pairs and Code Optimization
48:02
Input/Output Pairs and Code Optimization
48:02 - 1:00:05
Explains how input and output pairs are created for training and discusses code optimizations for efficient GPU utilization.
Input/Output Pairs Next Token Prediction Batch Creation Pin Memory Non-Blocking GPU Transfer
Token Embeddings and Layer Normalization
1:00:02
Token Embeddings and Layer Normalization
1:00:02 - 1:12:04
Focuses on the concept of token embedding and its importance in capturing semantic meaning, along with the introduction of layer normalization.
Token Embedding Layer Normalization Multi-Head Attention Next Token Prediction
Attention Mechanism and Contextual Understanding
1:12:03
Attention Mechanism and Contextual Understanding
1:12:03 - 1:24:06
Explains the attention mechanism in detail, including multi-head attention and causal attention, for improved next word prediction.
Attention Mechanism Context Vector Multi-Head Attention Queries, Keys, Values Causal Attention
Transformer Block and Output Layer
This module details the inner workings of the transformer block, including mathematical operations, ...
This module details the inner workings of the transformer block, including mathematical operations, layers, connections, and the output layer for next token prediction.
Causal Self-Attention and Transformer Block
1:24:03
Causal Self-Attention and Transformer Block
1:24:03 - 1:36:08
Explains the causal self-attention block and the transformer block, detailing the mathematical operations and layers involved.
Causal Self-Attention Transformer Block Shortcut Connections Layer Normalization Feed-Forward Neural Network
Transformer Blocks and Output Layer
1:36:06
Transformer Blocks and Output Layer
1:36:06 - 1:48:12
Explains how the input passes through multiple transformer blocks and the output layer to produce a logits tensor for next token prediction.
Transformer Blocks Output Layer Logits Tensor Next Token Prediction Parameter Initialization
Loss Function and Training Configuration
This module covers the GPT configuration, including hyperparameters, and the calculation of the loss...
This module covers the GPT configuration, including hyperparameters, and the calculation of the loss function used to train the language model.
GPT Configuration and Loss Function Calculation
1:48:09
GPT Configuration and Loss Function Calculation
1:48:09 - 2:00:15
Explains the GPT configuration and details the loss function calculation, comparing predicted tokens with target tokens.
GPT Configuration Transformer Blocks Attention Heads Logits Matrix Softmax Application Loss Function Calculation
Cross-Entropy Loss and Model Evaluation
2:00:11
Cross-Entropy Loss and Model Evaluation
2:00:11 - 2:12:14
Explains the concept of cross-entropy loss and introduces the 'estimate loss' function for evaluating model performance.
Cross-Entropy Loss Negative Log Likelihood Logits Matrix Target Token Ids Estimate Loss Function
Training Techniques and Optimization
This module focuses on advanced training techniques like mixed precision, gradient accumulation, and...
This module focuses on advanced training techniques like mixed precision, gradient accumulation, and learning rate scheduling, along with the backpropagation process and parameter updates.
Advanced Training Techniques
2:12:12
Advanced Training Techniques
2:12:12 - 2:24:15
Explains advanced training techniques like automatic mixed precision, gradient accumulation, and learning rate warm-up/decay.
Automatic Mixed Precision Gradient Accumulation Adamw Optimizer Learning Rate Warm-Up/Decay Hyperparameter Tuning
Backpropagation and Parameter Updates
2:24:13
Backpropagation and Parameter Updates
2:24:13 - 2:36:16
Explains the backpropagation process, gradient accumulation, parameter updates using the AdamW optimizer, and model evaluation.
Backpropagation Gradient Accumulation Adamw Optimizer Learning Rate Update Inference Pipeline
Inference and Applications
This module explains the text generation process using the trained model and discusses potential app...
This module explains the text generation process using the trained model and discusses potential applications of small language models.
Text Generation and Sampling Techniques
2:36:13
Text Generation and Sampling Techniques
2:36:13 - 2:48:03
Explains the generate function in the GPT class, detailing how the model generates text using techniques like top-k and temperature scaling.
GPT Generate Function Token Generation Top-K Sampling Temperature Scaling Small Language Model Applications
Questions This Video Answers
What is Byte Pair Encoding (BPE) and why is it used?
Byte Pair Encoding is a subword tokenization technique used to efficiently represent words by breaking them into smaller, frequently occurring units. This helps in handling out-of-vocabulary words and reduces the vocabulary size compared to word-based tokenization.

How does the attention mechanism work in a language model?
The attention mechanism allows the model to focus on different parts of the input sequence when predicting the next token. It calculates a context vector based on the relationships between tokens, augmenting the input embeddings with contextual information.

What are some practical applications of small language models?
Small language models can be used in resource-constrained environments, personalized learning applications, content generation, and as building blocks for more complex AI systems. Their smaller size makes them easier to deploy and train on limited hardware.

What is the role of the loss function in training a language model?
The loss function quantifies the difference between the model's predictions and the actual target tokens. It guides the training process by providing a signal for adjusting the model's parameters to minimize the error and improve prediction accuracy.

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