ForLion: An R Package for Finding Optimal Experimental Designs with Mixed Factors

TL;DR

ForLion is an R package that efficiently finds optimal experimental designs with mixed factors, supporting various models and providing tools for approximate and exact design construction, including robustness under parameter uncertainty.

Contribution

The paper introduces the ForLion package implementing algorithms for constructing locally and robust EW D-optimal designs for experiments with mixed factors and models.

Findings

Supports linear, generalized linear, and multinomial logistic models.

Provides tools for approximate and exact design conversion.

Includes tutorials demonstrating practical usage.

Abstract

Optimal design is crucial for experimenters to maximize the information collected from experiments and estimate the model parameters most accurately. ForLion algorithms have been proposed to find D-optimal designs for experiments with mixed types of factors. In this paper, we introduce the ForLion package which implements the ForLion algorithm to construct locally D-optimal designs and the Expected Weighted (EW) ForLion algorithm to generate robust EW D-optimal designs, which maximize the determinant of the expected Fisher information matrix under parameter uncertainty. The package supports experiments under linear models (LM), generalized linear models (GLM), and multinomial logistic models (MLM) with continuous, discrete, or mixed-type factors. It provides both optimal approximate designs and an efficient function converting approximate designs into exact designs with integer-valued allocations of experimental units. Tutorials are included to show the package's usage across different scenarios.