Model Optimization: Quantization, Pruning, Distillation

Introduction: Making Models Faster and Smaller

Your neural network achieves 95% accuracy... but it's 500MB, takes 2 seconds per prediction, and requires a GPU. Production systems need fast, small, and efficient models.

Model optimization reduces size and latency while maintaining accuracy.

Key Techniques:

  • Quantization (reduce precision)
  • Pruning (remove weights)
  • Knowledge distillation (teacher-student)
  • Compilation (optimize computation graph)

Learning Objectives

  • Understand model optimization trade-offs
  • Apply quantization techniques
  • Implement model pruning
  • Use knowledge distillation
  • Optimize inference with compilation
  • Choose appropriate optimization for use case

1. Why Optimize?

The Optimization Trade-off

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2. Quantization

Idea: Use lower precision (INT8 instead of FP32) for weights and activations.

FP32 (32-bit float): Standard training precision INT8 (8-bit integer): 4x smaller, 2-4x faster inference

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3. Model Pruning

Idea: Remove unimportant weights (set to zero) to reduce model size.

Types:

  • Unstructured pruning: Remove individual weights
  • Structured pruning: Remove entire neurons/channels

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4. Knowledge Distillation

Idea: Train a small "student" model to mimic a large "teacher" model.

Process:

  1. Train large, accurate teacher model
  2. Use teacher's outputs as "soft targets"
  3. Train smaller student to match teacher

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5. Model Compilation

Idea: Optimize the computation graph for specific hardware.

Tools:

  • TensorRT (NVIDIA GPUs)
  • ONNX Runtime
  • TensorFlow Lite (mobile/edge)
  • Apache TVM

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6. Optimization Decision Guide

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Key Takeaways

Quantization reduces precision (FP32 → INT8) for 4x smaller models

Pruning removes unimportant weights for sparse models

Knowledge distillation trains small students to mimic large teachers

Compilation optimizes computation graph for hardware

Trade-offs: Speed/size gains vs. accuracy loss

Combine techniques for maximum optimization


What's Next?

Final lesson: Production Best Practices – security, reliability, scalability, and real-world deployment strategies!