openfst
weighted finitestate transducers library
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Package versionopenfst1.8.2

MaintainerThe OpenBSD ports mailinglist
OpenFst is a library for constructing, combining, optimizing, and
searching weighted finitestate transducers (FSTs). Weighted
finitestate transducers are automata where each transition has an input
label, an output label, and a weight. The more familiar finitestate
acceptor is represented as a transducer with each transition's input and
output label equal. Finitestate acceptors are used to represent sets of
strings (specifically, regular or rational sets); finitestate
transducers are used to represent binary relations between pairs of
strings (specifically, rational transductions). The weights can be used
to represent the cost of taking a particular transition.
FSTs have key applications in speech recognition and synthesis, machine
translation, optical character recognition, pattern matching, string
processing, machine learning, information extraction and retrieval among
others. Often a weighted transducer is used to represent a probabilistic
model (e.g., an ngram model, pronunciation model). FSTs can be
optimized by determinization and minimization, models can be applied to
hypothesis sets (also represented as automata) or cascaded by
finitestate composition, and the best results can be selected by
shortestpath algorithms.
This library was developed by contributors from Google Research and
NYU's Courant Institute. It is intended to be comprehensive, flexible,
efficient and scale well to large problems. It has been extensively
tested. It is an open source project distributed under the Apache
license.