Complex Constraint Abstraction: Global Constraint Visualisation

Global Constraint Catalogue: Past, Present and Future

“…This was for instance the case in the DISCIPL project where visualisation tools were developed for the cumulative, the cycle and the diffn constraints [74]. However, in the context of the global constraint catalogue, this is clearly not a feasible approach since we have too many global constraints.…”

“…Describing all potential global constraints with this approach is an endless task, when one considers the many ways of combining global constraints. This is even worse if, in the long term, we aim at providing other services such as visualisation [74], explanations [73], soft global constraints [7,60,80], learning implied global constraints [21], or specialised heuristics for each global constraint.…”

“…From an early time, global constraints have been used for their strong pruning power thanks to efficient specialised filtering algorithms that take advantage of the structure of the constraints they consider (see for instance, the filtering algorithms proposed for the alldifferent constraint [24,29,52,53,56,63,68]). More recently, it became clear that global constraints are not only useful for their deductive power, but that they also have a central role to play in modelling languages for problem solving [77], in local search [78], in symmetry breaking [65], in visualisation tools for debugging constraint programs [74], in linear programming tools [46] or in deriving efficient heuristics [41] based on their internal status.…”

“…Actually, the procedural side of a global constraint may be any code for detecting the constraint infeasibility or for filtering the variable domains, but also, for generating a graphical representation [74], for constructing a heuristic based on the global constraint description, for evaluating the cost violation [7] associated with a ground instance...…”

Toward sustainable development in constraint programming

“…Visualisation [12,14] and explanation [16] can be very helpful in providing this information to the user. Special visualisers for some specific global constraints were already defined in [30], but even the more generic CP-Viz tool [31] requires hard-coded extensions for each global constraint. For some uses it may be sufficient to visualise just the state of the decision variables of the constraint.…”