Distill n' Explain: explaining graph neural networks using simple surrogates

Fuente: arXiv
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Main Authors: Pereira, Tamara, Nascimento, Erik, Resck, Lucas E., Mesquita, Diego, Souza, Amauri
Format: Preprint
Published: 2023
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author Pereira, Tamara
Nascimento, Erik
Resck, Lucas E.
Mesquita, Diego
Souza, Amauri
author_facet Pereira, Tamara
Nascimento, Erik
Resck, Lucas E.
Mesquita, Diego
Souza, Amauri
contents Explaining node predictions in graph neural networks (GNNs) often boils down to finding graph substructures that preserve predictions. Finding these structures usually implies back-propagating through the GNN, bonding the complexity (e.g., number of layers) of the GNN to the cost of explaining it. This naturally begs the question: Can we break this bond by explaining a simpler surrogate GNN? To answer the question, we propose Distill n' Explain (DnX). First, DnX learns a surrogate GNN via knowledge distillation. Then, DnX extracts node or edge-level explanations by solving a simple convex program. We also propose FastDnX, a faster version of DnX that leverages the linear decomposition of our surrogate model. Experiments show that DnX and FastDnX often outperform state-of-the-art GNN explainers while being orders of magnitude faster. Additionally, we support our empirical findings with theoretical results linking the quality of the surrogate model (i.e., distillation error) to the faithfulness of explanations.
format Preprint
id arxiv_https___arxiv_org_abs_2303_10139
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Distill n' Explain: explaining graph neural networks using simple surrogates
Pereira, Tamara
Nascimento, Erik
Resck, Lucas E.
Mesquita, Diego
Souza, Amauri
Machine Learning
Artificial Intelligence
Explaining node predictions in graph neural networks (GNNs) often boils down to finding graph substructures that preserve predictions. Finding these structures usually implies back-propagating through the GNN, bonding the complexity (e.g., number of layers) of the GNN to the cost of explaining it. This naturally begs the question: Can we break this bond by explaining a simpler surrogate GNN? To answer the question, we propose Distill n' Explain (DnX). First, DnX learns a surrogate GNN via knowledge distillation. Then, DnX extracts node or edge-level explanations by solving a simple convex program. We also propose FastDnX, a faster version of DnX that leverages the linear decomposition of our surrogate model. Experiments show that DnX and FastDnX often outperform state-of-the-art GNN explainers while being orders of magnitude faster. Additionally, we support our empirical findings with theoretical results linking the quality of the surrogate model (i.e., distillation error) to the faithfulness of explanations.
title Distill n' Explain: explaining graph neural networks using simple surrogates
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2303.10139