On lazy and eager interactive reconfiguration

An interactive configuration tool needs to provide feedback to the user on possible further decisions while respecting constraints of the product being configured. In the presence of a large number of product features, it reduces the configuration effort if users can start from a default configuration and adapt only those features that are important to them. Hence, rather than completing an empty configuration (empty product), it is easier to move from one complete configuration to another (from one product to another). This paper shows how to provide tool support for this approach to interactive configuration. Two types of algorithms, based on recent advancements in SAT technology, are introduced: lazy and eager. While the eager provides more information to the user, the lazy scales to configuration models with tens of thousands of features. This is confirmed by an experimental evaluation carried out with the implemented prototype.