The SPIRAL algorithm consists of two major steps, denoted by SPIRAL G and SPIRAL L in Figure 4.2. In the first step, the fundamental principle of the SPIRAL algorithm is to grow a high weight, planar, hexagonal adjacency graph in a greedy fashion. In the second step, this graph is converted into a block layout with all rectangular departments and with material handling aisles parallel to one of the hexagon axes.
The SPIRAL program contains a collection of algorithms. These algorithms either construct a planar hexagonal adjacency or create a block and are called graph and layout algorithms, respectively.
You have the option of selecting one single design algorithm to be executed next or to select the execution of all possible combinations of algorithms. If you choose the latter, the program will execute a number of algorithms in sequential order. It also maintains the best adjacency score, the best efficiency, and the best shape adjusted distance score obtained by the algorithms for this project.