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TinyTorch/docs/module-audit.md
Vijay Janapa Reddi 768aea4aa9 Add comprehensive multi-channel Conv2D support to Module 06 (Spatial)
MAJOR FEATURE: Multi-channel convolutions for real CNN architectures

Key additions:
- MultiChannelConv2D class with in_channels/out_channels support
- Handles RGB images (3 channels) and arbitrary channel counts
- He initialization for stable training
- Optional bias parameters
- Batch processing support

Testing & Validation:
- Comprehensive unit tests for single/multi-channel
- Integration tests for complete CNN pipelines
- Memory profiling and parameter scaling analysis
- QA approved: All mandatory tests passing

CIFAR-10 CNN Example:
- Updated train_cnn.py to use MultiChannelConv2D
- Architecture: Conv(3→32) → Pool → Conv(32→64) → Pool → Dense
- Demonstrates why convolutions matter for vision
- Shows parameter reduction vs MLPs (18KB vs 12MB)

Systems Analysis:
- Parameter scaling: O(in_channels × out_channels × kernel²)
- Memory profiling shows efficient scaling
- Performance characteristics documented
- Production context with PyTorch comparisons

This enables proper CNN training on CIFAR-10 with ~60% accuracy target.
2025-09-22 10:26:13 -04:00

4.7 KiB

TinyTorch Module Audit: Essential vs Extra Components

Overview

This audit examines what components are NEEDED for each milestone vs EXTRA components that enhance the framework but aren't strictly necessary.


Part I: MLPs (Target: XORNet)

Module 02: Tensor

ESSENTIAL for XORNet:

  • Basic Tensor class with data storage
  • Addition, subtraction, multiplication
  • Matrix multiply (for layers)
  • Shape, reshape operations

EXTRA (but good for framework):

  • Broadcasting ✓ (nice but XOR doesn't need)
  • Fancy indexing ✓
  • Statistical operations (mean, sum, std) ✓
  • Comparison operators ✓

Module 03: Activations

ESSENTIAL for XORNet:

  • ReLU ✓ (used in XORNet)
  • Sigmoid (could use for XOR output)

EXTRA (but good for framework):

  • Tanh ✓ (alternative to ReLU)
  • Softmax ✓ (not needed for XOR, but needed for CIFAR-10)
  • ActivationProfiler ✓ (pedagogical tool)

Module 04: Layers

ESSENTIAL for XORNet:

  • Dense layer ✓ (fully connected)
  • Weight initialization
  • Forward pass

EXTRA:

  • Different initialization strategies (Xavier, He, etc.)
  • Bias option

Module 05: Networks

ESSENTIAL for XORNet:

  • Sequential model ✓
  • Forward pass through layers

EXTRA:

  • Model summary/printing
  • Parameter counting

Part II: CNNs (Target: CIFAR-10)

Module 06: Spatial

ESSENTIAL for CNN CIFAR-10:

  • Conv2D ✓ (the key innovation!)
  • MaxPool2D ✓ (for downsampling)

EXTRA (but pedagogically valuable):

  • Different padding modes
  • Stride options
  • AvgPool2D (alternative pooling)
  • Multiple filter support

Module 07: DataLoader

ESSENTIAL for CIFAR-10:

  • CIFAR10Dataset ✓
  • DataLoader with batching ✓
  • Shuffling ✓

EXTRA:

  • Data augmentation (but helps accuracy!)
  • Other datasets (MNIST, etc.)
  • Prefetching/parallel loading

Module 08: Autograd

ESSENTIAL for CIFAR-10:

  • Variable class ✓
  • Backward pass ✓
  • Gradient computation ✓

EXTRA:

  • Computation graph visualization
  • Gradient checking
  • Higher-order derivatives

Module 09: Optimizers

ESSENTIAL for CIFAR-10:

  • SGD (basic, could work)
  • Adam ✓ (used in CIFAR-10, converges faster)

EXTRA:

  • Learning rate scheduling
  • Momentum variants
  • RMSprop, AdaGrad

Module 10: Training

ESSENTIAL for CIFAR-10:

  • Training loop ✓
  • CrossEntropyLoss ✓
  • Basic evaluation ✓

EXTRA (but very useful):

  • Checkpointing ✓
  • Early stopping ✓
  • Metrics tracking ✓
  • Validation splits ✓
  • MeanSquaredError (for XOR)

Part III: Transformers (Target: TinyGPT)

Module 11: Embeddings

ESSENTIAL for TinyGPT:

  • Token embedding layer
  • Positional encoding (sinusoidal or learned)

EXTRA:

  • Multiple embedding types
  • Embedding dropout

Module 12: Attention

ESSENTIAL for TinyGPT:

  • Multi-head attention ✓ (already implemented!)
  • Scaled dot-product attention ✓
  • Causal masking ✓

EXTRA:

  • Different attention variants
  • Attention visualization

Module 13: Normalization

ESSENTIAL for TinyGPT:

  • LayerNorm (critical for transformer stability)

EXTRA:

  • BatchNorm (not used in transformers)
  • GroupNorm, InstanceNorm

Module 14: Transformers

ESSENTIAL for TinyGPT:

  • TransformerBlock (attention + FFN + residual)
  • Positional encoding integration
  • Stack of blocks

EXTRA:

  • Encoder-decoder architecture
  • Cross-attention

Module 15: Generation

ESSENTIAL for TinyGPT:

  • Autoregressive generation
  • Temperature sampling
  • Greedy decoding

EXTRA:

  • Beam search
  • Top-k, Top-p sampling
  • Repetition penalty

Summary

Truly Minimal Path

If we wanted ONLY what's needed for milestones:

  • XORNet: Just needs Dense, ReLU, basic Tensor ops
  • CIFAR-10 MLP: Add DataLoader, Adam, CrossEntropyLoss
  • CIFAR-10 CNN: Add Conv2D, MaxPool2D
  • TinyGPT: Add Embeddings, Attention, LayerNorm, Generation

What We Have (Good Extras)

  • More activation choices: Good for experimentation
  • Better optimizers: Adam converges faster than SGD
  • Training utilities: Checkpointing, metrics (very practical!)
  • Profiling tools: Help understand performance

Missing Essentials

For Part III (TinyGPT) we still need to implement:

  1. Module 11: Embedding layer, positional encoding
  2. Module 13: LayerNorm
  3. Module 14: TransformerBlock
  4. Module 15: Generation strategies

Verdict

The current modules have a good balance of essential + useful extras. The extras are:

  • Pedagogically valuable (show alternatives)
  • Practically useful (checkpointing, better optimizers)
  • Framework completeness (makes TinyTorch feel real)

The only "bloat" might be multiple activation functions, but even those are good for showing students the options and tradeoffs.