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FixedFeatureAcquisitionFunction

As explained in Bayesian Optimization in Action

FixedFeatureAcquisitionFunction is a BoTorch wrapper that evaluates or optimizes an acquisition function while holding selected input features at fixed values.

FixedFeatureAcquisitionFunction wraps a BoTorch acquisition function so optimization can vary some inputs while holding selected features at specified values. This is useful when a multifidelity model contains both search variables and a fidelity variable, but the policy should operate at one chosen fidelity. section 9.7 section 9.4

Configure the wrapper by supplying:

  • An acquisition function, such as PosteriorMean or qMaxValueEntropy. section 9.4
  • The full input dimension d, the feature indices in columns, and their fixed values in values. section 9.4
  • A standard optimizer such as optimize_acqf to maximize the wrapped score over the remaining dimensions. section 9.4

Optimize the high-fidelity posterior mean

For a two-dimensional model whose second dimension represents fidelity, wrap PosteriorMean(model) with columns=[1] and values=[1]. optimize_acqf then searches for the posterior-mean maximizer while keeping fidelity at its high-fidelity value. The resulting point can be augmented with a fidelity value of 1 for final evaluation. section 9.4

How Bayesian Optimization in Action covers it

How deep it goes
Defines initialization parameters and optimization workflow, but does not explain the wrapper’s internal implementation.
Examples
Uses a two-dimensional search space with fidelity column 1 fixed at value 1 for posterior-mean recommendations.
What it assumes
Assumes a multifidelity Gaussian-process model and familiarity with acquisition functions and Bayesian-optimization optimization helpers.
What you can do after
Apply it via BoTorch and optimize_acqf to obtain acquisition-function optima under fixed feature values.
How it connects
Connects PosteriorMean, qMaxValueEntropy, optimize_acqf, and multifidelity optimization.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Bayesian Optimization in Action. The section links point to the parts of the book it draws on.