bwst | Burrows-Wheeler-Scott transform

bwst is a Go library. bwst has no bugs, it has no vulnerabilities and it has low support. You can download it from GitHub.

the burrows-wheeler-scott transform (called the burrows-wheeler transform "scottified" in existing literature, but that sounds silly) sorts together all infinitely repeated cycles of each lyndon word of the input, then takes the last character of each rotation of each lyndon word in the overall sorted order. of course, this description is about as intelligible as any of the existing literature on it for someone not intimately familiar with the concepts involved, and incomplete for someone who is. lyndon words are sequences which are less than any of the rotations of that sequence. "less than", that is, the order, is defined in "the usual lexicographical way": 'a' < 'b' by definition; 'aa' < 'ab' because the first positions are the same and the second position is lesser in 'aa'; 'ab' < 'ba' because 'ab' is lesser in the first position. for now, the order of sequences whose lengths are not equal is left undefined. a lyndon word is a sequence such that no matter how many times you take the rightmost (or leftmost) element and attach it to the left (or right, respectively), the result is never less than the word. by the chen-fox-lyndon theorem, every ordered sequence has a unique "lyndon factorization" of lyndon words, such that each word in the factorization is never greater than its predecessor, where order is here (not for the bwst algorithm) defined for words of unequal length such that if a is a prefix of b, then a <