Skeleton-Guided Learning for Shortest Path Search

TL;DR

This paper introduces a versatile learning-based framework for shortest path search on generic graphs, utilizing a skeleton graph and neural network to improve efficiency and accuracy without domain-specific features.

Contribution

The paper presents a novel skeleton graph structure and a hierarchical training strategy for effective, domain-agnostic shortest path search on complex graphs.

Findings

Achieves strong performance across diverse real-world graphs.

Reduces search space with model-driven pruning while maintaining accuracy.

Enables efficient path search through hierarchical graph partitioning.

Abstract

Shortest path search is a core operation in graph-based applications, yet existing methods face important limitations. Classical algorithms such as Dijkstra's and A* become inefficient as graphs grow more complex, while index-based techniques often require substantial preprocessing and storage. Recent learning-based approaches typically focus on spatial graphs and rely on context-specific features like geographic coordinates, limiting their general applicability. We propose a versatile learning-based framework for shortest path search on generic graphs, without requiring domain-specific features. At the core of our approach is the construction of a skeleton graph that captures multi-level distance and hop information in a compact form. A Skeleton Graph Neural Network (SGNN) operates on this structure to learn node embeddings and predict distances and hop lengths between node pairs. These predictions support LSearch, a guided search algorithm that uses model-driven pruning to reduce the search space while preserving accuracy. To handle larger graphs, we introduce a hierarchical training strategy that partitions the graph into subgraphs with individually trained SGNNs. This structure enables HLSearch, an extension of our method for efficient path search across graph partitions. Experiments on five diverse real-world graphs demonstrate that our framework achieves strong performance across graph types, offering a flexible and effective solution for learning-based shortest path search.