PWL#2: RRB-Trees: Efficient Immutable Vectors

Abstract

Immutable vectors are a convenient data structure for functional programming and part of the standard library of modern languages like Clojure and Scala. The common implementation is based on wide trees with a fixed number of children per node, which allows fast indexed lookup and update operations. In this paper, the authors extend the vector data type with a new underlying data structure, Relaxed Radix Balanced Trees (RRB-Trees), and show how this structure allows immutable vector concatenation, insert-at and splits in O(logN) time while maintaining the index, update and iteration speeds of the original vector data structure.

Chris Bilson will be presenting this paper followed by a Q&A session.

Link: RRB-Trees: Efficient Immutable Vectors