Instance generation via generator instances

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)
14 Downloads (Pure)


Access to good benchmark instances is always desirable when developing new algorithms, new constraint models, or when comparing existing ones. Hand-written instances are of limited utility and are time-consuming to produce. A common method for generating instances is constructing special purpose programs for each class of problems. This can be better than manually producing instances, but developing such instance generators also has drawbacks. In this paper, we present a method for generating graded instances completely automatically starting from a class-level problem specification. A graded instance in our present setting is one which is neither too easy nor too difficult for a given solver. We start from an abstract problem specification written in the Essence language and provide a system to transform the problem specification, via automated type-specific rewriting rules, into a new abstract specification which we call a generator specification. The generator specification is itself parameterised by a number of integer parameters; these are used to characterise a certain region of the parameter space. The solutions of each such generator instance form valid problem instances. We use the parameter tuner irace to explore the space of possible generator parameters, aiming to find parameter values that yield graded instances. We perform an empirical evaluation of our system for five problem classes from CSPlib, demonstrating promising results.
Original languageEnglish
Title of host publicationPrinciples and Practice of Constraint Programming
Subtitle of host publication25th International Conference, CP 2019, Stamford, CT, USA, September 30 – October 4, 2019, Proceedings
EditorsThomas Schiex, Simon de Givry
Place of PublicationCham
ISBN (Electronic)9783030300487
ISBN (Print)9783030300470
Publication statusPublished - 2019
Event25th International Conference on Principles and Practice of Constraint Programming (CP 2019) - Stamford, United States
Duration: 30 Sept 20194 Oct 2019
Conference number: 25

Publication series

NameLecture Notes in Computer Science (Programming and Software Engineering)
ISSN (Print)0302-9743


Conference25th International Conference on Principles and Practice of Constraint Programming (CP 2019)
Abbreviated titleCP 2019
Country/TerritoryUnited States
Internet address


  • Automated modelling
  • Instance generation
  • Parameter tuning


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