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Solving the Optimal Experiment Design Problem with Mixed-Integer Convex Methods

Deborah Hendrych, Mathieu Besançon, Sebastian Pokutta

TL;DR

This work addresses solving the Mixed-Integer Convex Optimal Experiment Design Problem by preserving problem structure and leveraging the Boscia.jl framework to solve node relaxations with Frank-Wolfe methods. It introduces a unified nonlinear formulation over a truncated simplex, proves convergence under Lipschitz smoothness or generalized self-concordance, and demonstrates superior performance on large-scale OEDP instances versus traditional MINLP approaches. The study focuses on D- and A-optimal criteria (and GTI generalizations), presents multiple solver paradigms (Boscia, OA, Direct Conic, SOCP, Co-BnB), and provides extensive empirical results showing faster solution times and higher optimality rates for Boscia on challenging problems. This approach enables scalable, structure-preserving optimization for experimental design with practical implications for statistical estimation and engineering applications.

Abstract

We tackle the Optimal Experiment Design Problem, which consists of choosing experiments to run or observations to select from a finite set to estimate the parameters of a system. The objective is to maximize some measure of information gained about the system from the observations, leading to a convex integer optimization problem. We leverage Boscia.jl, a recent algorithmic framework, which is based on a nonlinear branch-and-bound algorithm with node relaxations solved to approximate optimality using Frank-Wolfe algorithms. One particular advantage of the method is its efficient utilization of the polytope formed by the original constraints which is preserved by the method, unlike alternative methods relying on epigraph-based formulations. We assess the method against both generic and specialized convex mixed-integer approaches. Computational results highlight the performance of the proposed method, especially on large and challenging instances.

Solving the Optimal Experiment Design Problem with Mixed-Integer Convex Methods

TL;DR

This work addresses solving the Mixed-Integer Convex Optimal Experiment Design Problem by preserving problem structure and leveraging the Boscia.jl framework to solve node relaxations with Frank-Wolfe methods. It introduces a unified nonlinear formulation over a truncated simplex, proves convergence under Lipschitz smoothness or generalized self-concordance, and demonstrates superior performance on large-scale OEDP instances versus traditional MINLP approaches. The study focuses on D- and A-optimal criteria (and GTI generalizations), presents multiple solver paradigms (Boscia, OA, Direct Conic, SOCP, Co-BnB), and provides extensive empirical results showing faster solution times and higher optimality rates for Boscia on challenging problems. This approach enables scalable, structure-preserving optimization for experimental design with practical implications for statistical estimation and engineering applications.

Abstract

We tackle the Optimal Experiment Design Problem, which consists of choosing experiments to run or observations to select from a finite set to estimate the parameters of a system. The objective is to maximize some measure of information gained about the system from the observations, leading to a convex integer optimization problem. We leverage Boscia.jl, a recent algorithmic framework, which is based on a nonlinear branch-and-bound algorithm with node relaxations solved to approximate optimality using Frank-Wolfe algorithms. One particular advantage of the method is its efficient utilization of the polytope formed by the original constraints which is preserved by the method, unlike alternative methods relying on epigraph-based formulations. We assess the method against both generic and specialized convex mixed-integer approaches. Computational results highlight the performance of the proposed method, especially on large and challenging instances.
Paper Structure (40 sections, 29 theorems, 107 equations, 7 figures, 6 tables)

This paper contains 40 sections, 29 theorems, 107 equations, 7 figures, 6 tables.

Key Result

Theorem 3.2

The functions $f_F(\mathbf{x}) := -\log\det\left(X_C(\mathbf{x})\right)$ and $g_F(\mathbf{x}) := \mathop{\mathrm{Tr}}\nolimits\left(\left(X_C(\mathbf{x})\right)^{-p}\right)$ for $p\in {\mathbb R} _{>0}$ are $L$-smooth on $x\in {\mathbb R} _{\geq 0}$ with Lipschitz constants and respectively.

Figures (7)

  • Figure 1: A schematic representation of the feasible region $\mathcal{P}$, the domain of the objective $\mathcal{D}$ and the convex hull of vertices that are both feasible and in the domain denoted as $\mathcal{W}$.
  • Figure 2: Trajectory of the dual gap at the root node compared to $1/2t$, $1/t^2$ and $1/e^{ct}$.
  • Figure 3: Geometric mean and geometric standard deviation of the absolute gap between the incumbent and lower bound over the conditioning of the problem.
  • Figure 4: The number of instances solved to optimality over time for the A-Optimal Problem and D-Optimal Problem with both data sets. The upper plots are with the inpdendent data set, the lower ones with correlated data. Note that SCIP+OA is not applicable on the Optimal Problems.
  • Figure 5: The number of instances solved to optimality over time for the A-Fusion Problem and D-Fusion Problem with both data sets. The upper plots are with the independent data set, the lower ones with correlated data.
  • ...and 2 more figures

Theorems & Definitions (68)

  • Remark
  • Definition 2.1: Information Function pukelsheim2006optimal
  • Definition 2.2: Matrix mean
  • Remark
  • Remark
  • Remark
  • Definition 3.1
  • Theorem 3.2
  • proof
  • Theorem 3.3
  • ...and 58 more