TL;DR

Custom architectures needed when: unique data modality, specialized task, performance requirements, or research. Design process: define problem, choose components, implement, and iterate.

When to build custom

  • Novel data types (sensors, specialized domains)
  • Unique task requirements
  • Extreme performance needs
  • Research contributions
  • Existing models insufficient

Design considerations

Inductive biases: What assumptions help the model?
Scalability: Can it handle your data volume?
Efficiency: Compute and memory constraints
Interpretability: Need to explain decisions?

Architecture components

Encoders: Process inputs to representations
Attention: Focus on relevant parts
Pooling: Aggregate information
Decoders: Generate outputs
Skip connections: Preserve information flow

Design process

  1. Understand problem deeply
  2. Survey existing work
  3. Identify architectural needs
  4. Start simple
  5. Implement and benchmark
  6. Iterate and refine

Common patterns

  • Encoder-decoder for sequence-to-sequence
  • Attention for variable-length inputs
  • Hierarchical for multi-scale
  • Graph networks for relational data

Testing and validation

  • Ablation studies (remove components)
  • Compare to baselines
  • Analyze failure modes
  • Verify inductive biases help