Relative Lempel-Ziv with Constant-Time Random Access

Relative Lempel-Ziv [1] (RLZ) is a variant of LZ77 that can compress collections of similar genomes well, while still allowing fast random access to them. We implemented RLZ using compressed bit vectors to support constant-time random access at the cost of sublinear extra space. We compared our implementation of RLZ to Deorowicz and Grabowski´s GDC [11] scheme and achieved comparable compression and much smaller access times for short substrings.