Custom

Custom fractional design — one defining relation expressed as a list of "words". A defining relation has the algebraic form I = w1 = w2 = ... where each word w_i is a product of factors named by 1-based index. Example: the relation I = 124 = 135 = 2345 has three words and encodes as [[1,2,4], [1,3,5], [2,3,4,5]]. The engine glue maps each word to a Set<Int> and the list to a Set<Set<Int>> for the substrate's TwoLevelFactorialDesign.fractionalIterator(relation, sign). The fraction exponent p equals the word count; the realised design is 2^(k-p).