,
Isabel Catalá
,
Unai López
,
Miguel A. Salido
Creative Commons Attribution 4.0 International license
Benchmarking scheduling instances solely by nominal size is often misleading: instances with the same number of jobs and machines can differ by orders of magnitude in empirical hardness. This paper proposes a supervised, solver-aligned difficulty estimator for Job-shop Scheduling Problem (JSP) instances. Building on standard disjunctive-graph descriptors and ISA-inspired distributional summaries, we construct an auditable hardness target from normalised multi-solver traces and learn to predict it from static instance features. A Random Forest regressor learns a bounded hardness score 𝒫(x) ∈ [0,1], from which balanced easy/medium/hard categories are induced. The empirical evaluation shows that the learned score is strongly aligned with solver-effort indicators, provides interpretable feature-level explanations, and provides evidence of partial ordinal transfer on classical JSPLIB benchmarks under distribution shift. The proposed framework provides a practical and interpretable basis for difficulty-aware benchmarking, instance selection, and solver-behaviour analysis beyond nominal size parameters.
@InProceedings{perez_et_al:LIPIcs.CP.2026.45,
author = {P\'{e}rez, Christian and Catal\'{a}, Isabel and L\'{o}pez, Unai and Salido, Miguel A.},
title = {{Instance Space Analysis and Complexity Estimation for Scheduling Problems}},
booktitle = {32nd International Conference on Principles and Practice of Constraint Programming (CP 2026)},
pages = {45:1--45:19},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-432-1},
ISSN = {1868-8969},
year = {2026},
volume = {379},
editor = {Beldiceanu, Nicolas},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CP.2026.45},
URN = {urn:nbn:de:0030-drops-266770},
doi = {10.4230/LIPIcs.CP.2026.45},
annote = {Keywords: Job-shop Scheduling, Instance Space Analysis, Solver Hardness, Multi-solver supervision, Supervised Learning}
}