arXiv subjects

Benoît Chachuat

Publications and source records attributed to Benoît Chachuat.

3 recordsLinked to original sources

arXiv2026

Relaxation via Separable Estimators: Arithmetic and Implementation

This article presents an arithmetic, called superposition relaxation, for bracketing the graph of a multivariate factorable function on a compact domain between a pair of underestimating and overestimating functions that are both separable. Propagation rules are established for affine and nonlinear composition operations, with a focus on exploiting global monotonicity and convexity properties in the composition. The local convergence properties of this arithmetic are also analyzed in both the pointwise and Hausdorff sense, including conditions under which quadratic pointwise convergence propagates through composition. Parameterizations of the univariate summands in a superposition relaxation either as piecewise-constant or continuous piecewise-linear functions are discussed for a practical implementation. It is shown through numerical case studies that superposition relaxations can be consistently tighter than McCormick relaxations, including for the relaxation of artificial neural networks. But superposition relaxations also incur a higher computational cost than McCormick relaxations. Further investigations are thus warranted as applications in global optimization seek to balance a relaxation's tightness with its computational cost.

math.NA↗

arXiv2026

Learning with Embedded Linear Equality Constraints via Variational Bayesian Inference

Machine Learning is becoming more prevalent in science and engineering, but many approaches do not provide meaningful uncertainty estimates and predictions may also violate known physical knowledge. We propose a Bayesian framework to embed linear relationships across inputs and outputs into the learning process, whilst characterizing full predictive uncertainty over both the model parameters and the domain knowledge. We evaluated our method on learning the single particle battery model subject to voltage and energy balances, showing its ability to provide reduced credible intervals and constraint violations compared to standard Bayesian neural networks based on variational inference.

cs.LG↗

arXiv2025

A Decomposition Approach to Solving Numerical Constraint Satisfaction Problems on Directed Acyclic Graphs

Certifying feasibility in decision-making, critical in many industries, can be framed as a constraint satisfaction problem. This paper focuses on characterising a subset of parameter values from an a priori set that satisfy constraints on a directed acyclic graph of constituent functions. The main assumption is that these functions and constraints may be evaluated for given parameter values, but they need not be known in closed form and could result from expensive or proprietary simulations. This setting lends itself to using sampling methods to gain an inner approximation of the feasible domain. To mitigate the curse of dimensionality, the paper contributes new methodology to leverage the graph structure for decomposing the problem into lower-dimensional subproblems defined on the respective nodes. The working hypothesis that the Cartesian product of the solution sets yielded by the subproblems will tighten the a priori parameter domain, before solving the full problem defined on the graph, is demonstrated through four case studies relevant to machine learning and engineering. Future research will extend this approach to cyclic graphs and account for parametric uncertainty.

eess.SY↗