Pynini: A Python library for weighted finite-state grammar compilation

Abstract

We present Pynini, an open-source library for the compilation of weighted finitestate transducers (WFSTs) and pushdown transducers (PDTs) from strings, contextdependent rewrite rules, and recursive transition networks. Pynini uses the OpenFst library for encoding, modifying, and applying WFSTs and PDTs. We describe the design of this library and the algorithms and interfaces used for compilation, optimization, and application, and provide two illustrations of the library in use.