Optimization over Trained (and Sparse) Neural Networks: A Surrogate within a Surrogate

Fuente: arXiv
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Autori principali: Pham, Hung, Ren, Aiden, Tahir, Ibrahim, Tong, Jiatai, Serra, Thiago
Natura: Preprint
Pubblicazione: 2025
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author Pham, Hung
Ren, Aiden
Tahir, Ibrahim
Tong, Jiatai
Serra, Thiago
author_facet Pham, Hung
Ren, Aiden
Tahir, Ibrahim
Tong, Jiatai
Serra, Thiago
contents In constraint learning, we use a neural network as a surrogate for part of the constraints or of the objective function of an optimization model. However, the tractability of the resulting model is heavily influenced by the size of the neural network used as a surrogate. One way to obtain a more tractable surrogate is by pruning the neural network first. In this work, we consider how to approach the setting in which the neural network is actually a given: how can we solve an optimization model embedding a large and predetermined neural network? We propose surrogating the neural network itself by pruning it, which leads to a sparse and more tractable optimization model, for which we hope to still obtain good solutions with respect to the original neural network. For network verification and function maximization models, that indeed leads to better solutions within a time limit, especially -- and surprisingly -- if we skip the standard retraining step known as finetuning. Hence, a pruned network with worse inference for lack of finetuning can be a better surrogate.
format Preprint
id arxiv_https___arxiv_org_abs_2505_01985
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimization over Trained (and Sparse) Neural Networks: A Surrogate within a Surrogate
Pham, Hung
Ren, Aiden
Tahir, Ibrahim
Tong, Jiatai
Serra, Thiago
Optimization and Control
Machine Learning
In constraint learning, we use a neural network as a surrogate for part of the constraints or of the objective function of an optimization model. However, the tractability of the resulting model is heavily influenced by the size of the neural network used as a surrogate. One way to obtain a more tractable surrogate is by pruning the neural network first. In this work, we consider how to approach the setting in which the neural network is actually a given: how can we solve an optimization model embedding a large and predetermined neural network? We propose surrogating the neural network itself by pruning it, which leads to a sparse and more tractable optimization model, for which we hope to still obtain good solutions with respect to the original neural network. For network verification and function maximization models, that indeed leads to better solutions within a time limit, especially -- and surprisingly -- if we skip the standard retraining step known as finetuning. Hence, a pruned network with worse inference for lack of finetuning can be a better surrogate.
title Optimization over Trained (and Sparse) Neural Networks: A Surrogate within a Surrogate
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2505.01985