  A compressed full-text self-index occupies space close to that of the
compressed text and simultaneously allows fast pattern matching and random
access to the underlying text. Among the best compressed self-indexes, in
theory and in practice, are several members of the FM-index family. In this
paper, we describe new FM-index variants that combine nice theoretical
properties, simple implementation and improved practical performance. Our main
result is a new technique called fixed block compression boosting, which is a
simpler and faster alternative to optimal compression boosting and implicit
compression boosting used in previous FM-indexes.
