AutoML

[Ioannis Antoniadis]

References:

• https://link.springer.com/book/10.1007/978-3-030-05318-5

The discipline particular to our interest is more Model Selection and Hyperparameter Optimization (CASH) rather than meta-learning or AutoML (the last two are more general). There are several approaches to it:

• Black box optimization techniques:
  • Grid Search
  • Random Search
  • Bayesian Optimization
• Multi-fidelity techniques:
  • Bandits
• ..

[Ioannis Antoniadis]

Lecture on automl by Andreas Mueller and relevant slides:

• https://www.youtube.com/watch?v=tqtTHRwa8dE&ab_channel=AndreasMueller
• https://amueller.github.io/COMS4995-s19/slides/aml-13-parameter-tuning-automl/#1

Lecture on automl by Frank Hutter and Joaquin Vanschoren:

• https://www.youtube.com/watch?v=0eBR8a4MQ30&ab_channel=StevenVanVaerenbergh

Bayesian optimization:

• https://www.youtube.com/watch?v=C5nqEHpdyoE&t=17s&ab_channel=UAI2018
• https://arxiv.org/abs/1807.02811

Auto-Sklearn:

• https://arxiv.org/pdf/2007.04074.pdf

[Ioannis Antoniadis]

The problem:

• CASH: Combined Algorithm Selection and Hyperparameter Optimization

Two major classses of AutoML optimizers:

• Simple optimizers: only take care of model/hyperparameter selection
• Pipeline optimizers: may also include preprocessing components

Research on implemented tools:

• Auto-Weka:
  • Java
  • Pipeline optimizer
  • Bayesian optimization (SMAC)
• scikit-optimize:
  • Python, on top of scikit-learn
  • Simple optimizer
  • Bayesian optimization (SMAC)
• Hyperopt-sklearn
  • Python, on top of scikit-learn
  • Pipeline optimizer
  • Bayesian optimization (TPE)
• Auto-sklearn
  • Python, on top of scikit-learn, improvement of the Auto-Weka methodology
  • Bayesian optimization (SMAC)
• TPOT
  • Python, on top of scikit-learn
  • Pipeline optimizer
  • Genetic Programming (GP)
• Hyperband
  • Python
  • Pipeline optimizer
  • Bandit-based
• Optunity
  • Python
  • Simple optimizer
  • Includes several optimization algorithms:
    • Grid Search
    • Random Search
    • Particle Swarm Optimization
    • Nelder-Mead simplex
    • CMA-ES
    • TPE
    • Sobol sequences

Note: Major disadvantage of all of the state-of-the-art AutoML optimizers (either simple or pipeline) is that they provide pre-defined list of models and components to use.

[Ioannis Antoniadis]

Next up for auto-sklearn experimentation:

• Inspect the validation procedure of auto-sklearn and modify it to accommodate reduced validation sets (get rid of unlabelled points or else it'll crush)
• Incorporate additional AD models from PyOD