AN INTERACTIVE LAYOUT HEURISTIC BASED ON HEXAGONAL ADJACENCY GRAPHS

An efficient and interactive two-stage heuristic for the generation of block layouts is presented. During the first phase, it generates a hexagonal and maximum weight planar adjacency subgraph, which incorporates relationships with the outside of the layout in a consistent manner. The user can select a variety of (graph) construction algorithms based upon unary, binary, and ternary relationships tuples. The adjacency graph can be further improved by interior and exterior exchange procedures and a tight upper bound is derived based on an integer programming formulation. During the second phase, the adjacency graph is converted into a rectangular block layout, which yields all rectangularly shaped departments. Again the user can select various heuristic (block layout) construction and improvement procedures. The combined stages avoid some of the major disadvantages of graph-theoretic and area-based facility layout procedures. The results of the graph and block layout algorithms are compared with other algorithms for selected cases in the literature. In addition, the program was designed to allow for easy, interactive algorithm selection, sensitivity analysis, and manual construction by using an industry standard graphical user interface. Algorithms were purposely kept simple to decrease response time. Graphs, block layouts, and reports are immediately displayed, and can be readily printed or exported to other programs for computer-aided detailed layout design.