Parsing algorithms for dictionary compression on the PRAM
D. S. Hirschberg, Lynn M. Stauffer · 2002
Parallel algorithms for lossless data compression via dictionary compression using optimal and greedy parsing strategies are described. Dictionary compression removes redundancy by replacing substrings of the input by references to strings stored in a dictionary. Given a static dictionary stored as a suffix tree, the authors present a parallel random access concurrent read, concurrent write (PRAM CREW) algorithm for optimal compression which runs in O(M+log M log n) time with O(nM/sup 2/) processors, where it is assumed that M is the maximum length of any dictionary entry. They also describe an O(M+log n) time and O(n) processor algorithm for greedy parsing given a static or sliding-window dictionary. For sliding-window compression. A different approach finds the greedy parsing in O(log n) time using O(nM log M/log n) processors. Their algorithms are practical in the sense that their analysis elicits small constants.>