I am a PhD student at the University of St Andrews in Scotland funded by an EPSRC CASE studentship, sponsored by Microsoft Research.

My Research

Constraint programming has been used with great success to tackle a wide variety of combinatorial problems in industry and academia. However, in order to apply constraint programming tools to a particular domain, the problem must be modelled as a constgraint program. Constructing an effective model is a challenging task, which is perceived very much as an art by the constraints community with very few expert practitioners. This Creates a modelling bottleneck, preventing widespread access to the power of constraint technology. Previous has elevated the notion of a constraint model from an informal to a formal concept. This is the foundation for the Conjure automated modelling system, which refines a specification of a constraint problem, in the new abstract constraint specification language Essence, into a constraint model suitable for input to an existing constraint solver. One important modelling issue that Conjure only has minimal support for is symmetry*. Symmetry can be exploited to reduce substantially the effort needed to solve a constraint problem. My research will address this shortfall in Conjure, identifiying when symmetry occurs, and automating the exploitation of symmetry to produce efficient models.

Conjure will be improved to recognise when it makes a modelling decision that adds symmetry, and annotate each component of the models it generates with the group* corresponding to the symmetry it exhibits. The various symmetries introduced will be combined automatically into a single group-theoretic description. Given this description the symmetry can be broken automatically, either by adding extra constraints to the model before search, or by modifying the search procedure itself.

* a transformation that, given a (non-)solution always produces a (non-)solution.

** A mathematical term from group theory

A good place to learn about my work is the automated modelling web page.

[Publications] [Software] [Presentations] [Curriculum Vitae]

E-Mail: Address: Andy Grayland University of St Andrews Jack Cole Building North Haugh, St Andrews KY16 9SS, Scotland Phone: +44-1334-463257

Useful Contacts

• Ian Miguel University of St Andrews (first PhD supervisor)
• Colva Roney-Dougal University of St Andrews (second PhD supervisor)
• Andrea Rendl University of St Andrews
• Alan Frisch University of York
• Bernadette Martinez-Hernandez University of York
• Chris Jefferson University of Oxford
• Youssef Hamadi Microsoft Research Lab Cambridge

Some Random Links

Some energetic music from one of my favourite bands Kaleb

The University's unofficial internet forum The Sinner

The Royal Navy's unofficial internet forum Rum Ration