What do Constraint Programming Users Want to See? Exploring the Role of Visualisation in Profiling of Models and Search

Abstract

Constraint programming allows difficult combinatorial problems to be modelled declaratively and solved automatically. Advances in solver technologies over recent years have allowed the successful use of constraint programming in many application areas. However, when a particular solver's search for a solution takes too long, the complexity of the constraint program execution hinders the programmer's ability to profile that search and understand how it relates to their model. Therefore, effective tools to support such profiling and allow users of constraint programming technologies to refine their model or experiment with different search parameters are essential. This paper details the first user-centred design process for visual profiling tools in this domain. We report on: our insights and opportunities identified through an on-line questionnaire and a creativity workshop with domain experts carried out to elicit requirements for analytical and visual profiling techniques; our designs and functional prototypes realising such techniques; and case studies demonstrating how these techniques shed light on the behaviour of the solvers in practice.

A Framework for Creative Visualization-Opportunities Workshops

“…CVO workshops provide time for focused thinking about a collaboration, which allows stakeholders to share expertise and explore visualization opportunities. In feedback, one participant reported the workshop was "a good way to stop thinking about technical issues and try to see the big picture" [18].…”

“…In three of our projects, we used a series of workshops to explore opportunities, develop and iterate on prototypes, and evaluate the resulting visualizations in collaborations with cartographers [16], energy analysts [17], and defense analysts [88]. In three additional projects, we used a single workshop to jump-start applied collaborations with neuroscientists [35], constraint programmers [18], and psychiatrists [64]. Recently, we used two workshops to explore opportunities for funded collaboration with genealogists [34] and biologists [42].…”

“…Researchers often discover such problems through a lengthy process of interviews and observations with domain collaborators that can sometimes take months [39,56,80]. A number of recent projects, however, report on the use of workshops to characterize domain problems in just a few days of focused work [16,17,18,35,64,88]. More specifically, these workshops are creative visualization-opportunities workshops (CVO workshops), in which researchers and their collaborators explore opportunities for visualization in a domain [17].…”

“…In this paper, we -a group of visualization and creativity researchers who have been involved with every CVO workshop reported in the literature -reflect on our collective experience and offer guidance about how and why to use CVO workshops in applied visualization. More specifically, this paper results from a 2-year international collaboration in which we applied a methodology of critically reflective practice [7] to perform meta-analysis of our collective experience and research outputs from conducting 17 workshops in 10 visualization contexts [16,18,17,34,35,42,64,68,69,88], combined with a review of the workshop literature from the domains of design [3,14,38,72], software engineering [27,31,32,33,47,48,50], and creative problem-solving [13,19,21,59,66]. This paper's primary contribution is a framework for CVO workshops.…”

How People Visually Represent Discrete Constraint Problems

“…Recently Goodwin et al [25] described a user-centered design process for tools that visualize the solving process, building on earlier work by Shishmarev et al [72]. From an Information Visualization perspective Goodwin et al [25] looked at how different visualizations could be useful in the process of profiling constraint models. In addition, tools for layout constraints such as Auto Layout are also prevalent in IDEs.…”