AutoML limits and specifications
This topic describes the usage limits, supported regions, and search algorithms (TPE, GridSearch, Random, Evolution, GP, and PBT) of AutoML, along with the applicable scenarios of each algorithm.
Supported regions
AutoML is available in the following regions: China (Hangzhou), China (Shanghai), China (Beijing), China (Shenzhen), and China (Hong Kong).
Supported search algorithms
AutoML hyperparameter search supports the following algorithms and their typical scenarios.
TPE (Tree-structured Parzen Estimator)
TPE requires no additional dependencies and supports all search space types. It is the default HPO algorithm. Use it for complex, nonlinear, high-dimensional problems with high computational cost. It cannot discover relationships between parameters.
Reference: Algorithms for Hyper-Parameter Optimization.
GridSearch
GridSearch evenly divides the search space into a grid and evaluates every combination to find the best one. Use it when the search space is small.
Random
Random generates hyperparameter combinations. Like grid search, it divides the search space into a grid, but each trial randomly selects one hyperparameter set. Use it for nonlinear, high-dimensional problems with high computational cost.
Evolution
Evolution initializes from the search space. In each generation, it selects the better-performing parameters and mutates them to produce the next set of candidate hyperparameters. It requires multiple trials. The logic is simple and easy to extend.
The idea comes from Large-Scale Evolution of Image Classifiers.
GP (Gaussian process)
GP is a Bayesian optimization method that uses a Gaussian process to compute loss. As more data accumulates, the posterior distribution becomes more accurate and the optimization improves.
PBT (Population Based Training)
PBT is an asynchronous optimization algorithm for fixed compute resources. It optimizes a fixed number of models and their hyperparameters to improve performance, iterating on a single hyperparameter set to reach the optimum.
The algorithm comes from Population Based Training of Neural Networks.