Many statistical programs can now generate fractional‐replicate designs, but most depend on built‐in libraries of experimental plans. Relatively few have design generation algorithms that would give the user true flexibility in the numbers of tests, factors, and factor levels. Powerful search algorithms are now available for generating a wide range of blocked and fractional‐replicate designs using design keys, but these are mostly regular designs with pq units and factors with p, p2, … levels, where p is prime.
Many useful classes of irregular design also exist with numbers of units and factor levels which are not powers of p, and the construction rules for most of these use Galois fields and Hadamard matrices in some way. However, the underlying mathematics can be difficult. The aim of this paper is to collate algorithms to expedite the implementation of these structures in software and to present these in an accessible form to a wider community. The use of Galois fields and Hadamard matrices in generating important design classes, such as the fractional 2k Plackett–Burman and sk Addelman–Kempthorne designs, is then detailed.
Combining these algorithms with design key searches gives an arsenal of methods that can generate almost all existent balanced fractional‐replicate designs of sizes likely to be used in real‐world experimentation. These methods have all been implemented in the KEYFINDER program, which is available from the author, free of charge. Copyright © 2015 John Wiley & Sons, Ltd.