Score Function Gradient Estimation to Widen the Applicability of Decision-Focused Learning

Fuente: arXiv
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Autori principali: Silvestri, Mattia, Berden, Senne, Mandi, Jayanta, Mahmutoğulları, Ali İrfan, Amos, Brandon, Guns, Tias, Lombardi, Michele
Natura: Preprint
Pubblicazione: 2023
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author Silvestri, Mattia
Berden, Senne
Mandi, Jayanta
Mahmutoğulları, Ali İrfan
Amos, Brandon
Guns, Tias
Lombardi, Michele
author_facet Silvestri, Mattia
Berden, Senne
Mandi, Jayanta
Mahmutoğulları, Ali İrfan
Amos, Brandon
Guns, Tias
Lombardi, Michele
contents Many real-world optimization problems contain parameters that are unknown before deployment time, either due to stochasticity or to lack of information (e.g., demand or travel times in delivery problems). A common strategy in such cases is to estimate said parameters via machine learning (ML) models trained to minimize the prediction error, which however is not necessarily aligned with the downstream task-level error. The decision-focused learning (DFL) paradigm overcomes this limitation by training to directly minimize a task loss, e.g. regret. Since the latter has non-informative gradients for combinatorial problems, state-of-the-art DFL methods introduce surrogates and approximations that enable training. But these methods exploit specific assumptions about the problem structures (e.g., convex or linear problems, unknown parameters only in the objective function). We propose an alternative method that makes no such assumptions, it combines stochastic smoothing with score function gradient estimation which works on any task loss. This opens up the use of DFL methods to nonlinear objectives, uncertain parameters in the problem constraints, and even two-stage stochastic optimization. Experiments show that it typically requires more epochs, but that it is on par with specialized methods and performs especially well for the difficult case of problems with uncertainty in the constraints, in terms of solution quality, scalability, or both.
format Preprint
id arxiv_https___arxiv_org_abs_2307_05213
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Score Function Gradient Estimation to Widen the Applicability of Decision-Focused Learning
Silvestri, Mattia
Berden, Senne
Mandi, Jayanta
Mahmutoğulları, Ali İrfan
Amos, Brandon
Guns, Tias
Lombardi, Michele
Machine Learning
Artificial Intelligence
Many real-world optimization problems contain parameters that are unknown before deployment time, either due to stochasticity or to lack of information (e.g., demand or travel times in delivery problems). A common strategy in such cases is to estimate said parameters via machine learning (ML) models trained to minimize the prediction error, which however is not necessarily aligned with the downstream task-level error. The decision-focused learning (DFL) paradigm overcomes this limitation by training to directly minimize a task loss, e.g. regret. Since the latter has non-informative gradients for combinatorial problems, state-of-the-art DFL methods introduce surrogates and approximations that enable training. But these methods exploit specific assumptions about the problem structures (e.g., convex or linear problems, unknown parameters only in the objective function). We propose an alternative method that makes no such assumptions, it combines stochastic smoothing with score function gradient estimation which works on any task loss. This opens up the use of DFL methods to nonlinear objectives, uncertain parameters in the problem constraints, and even two-stage stochastic optimization. Experiments show that it typically requires more epochs, but that it is on par with specialized methods and performs especially well for the difficult case of problems with uncertainty in the constraints, in terms of solution quality, scalability, or both.
title Score Function Gradient Estimation to Widen the Applicability of Decision-Focused Learning
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2307.05213