Complexity Analysis vs. Engineering Design in CSP Algorithms: Contravening Conventional Wisdom Again

In this work we compare simple and ‘advanced’ algorithms that have been used to perform various functions in connection with constraint satisfaction problems (CSPs). These include algorithms for arc consistency, singleton arc consistency, arc consistency used with MAC, maxRPC algorithms, and algorithms for simple table reduction with non-binary constraints. In each case tested so far, we find tradeoffs between efficient implementations of basic operations like constraint checking and elaborations that allow a reduction in the number of these basic operations but add bookkeeping expenses. It is argued that such tradeoffs must be given more thorough consideration. This also suggests that there are interesting theoretical problems in this connection that have not yet received the attention they merit. Finally, the possibility that certain psychological biases have affected the analysis of algorithms in this area is considered.