NAVIGATION WITHIN A STRUCTURED SEARCH SPACE IN LAYOUT PROBLEMS

HeGeL-2 is a heuristic-based layout generator equipped with a nonseria l dynamic programming algorithm. HeGeL-2 finds optimal solutions to pl an-layout design (PLD) problems which are defined as problems that inv olve the allocation of a nontrivial number (ten or more) of design uni ts in one application. The search strategy HeGeL-2 uses is similar in some respects and dissimilar in others to human search behavior, which has been simulated in an earlier version of HeGeL-2. These similariti es include constraint relaxing strategies common to both versions. Dis similarities concern claims of optimality and 'goodness' of solutions measured by an objective function based on soft constraints. In this p aper, the general problem of navigation in a search space for layout p roblems is discussed in the context of a general-purpose formalism. Th rough this formalism several layout generators, including LOGS, WRIGHT , and HeGeL-2, are described.