Clojure interface to CRFSuite - a fast linear-chain CRF library.
This is a thin wrapper around jcrfsuite so we can use clojure data structures.
A linear chain CRF produces one symbol per output feature. For a simple task like POS-tagging:
NP --- conj --- NP --- VP --- dobj
| | | | |
| | | | |
John and mary like apples
The CRF is supplied english words (or some features corresponding to english words). The output is the POS tags.
Args:
xs: A list of sequences. A sequence is a clojure sequence of feature-vectors or feature-maps (a map from feature -> value).ys: Tags corresponding to sequences in xs.model-file: Location to dump model to.
user=> (train [
[{:feat1 2.0, :feat2 3.0}
{:feat1 3.0, :feat2 4.0}] ; the first sequence of features
[{:feat1 2.0, :feat2 3.0}
{:feat1 4.0, :feat2 5.0}] ; the second sequence of features
]
[
["y1", "y2"], ; tag-sequence
["y1", "y3"] ; tag-sequence
]
"trainmodel.crfsuite") ; destination
.
.
.
L-BFGS resulted in convergence
Total seconds required for training: 0.000
Storing the model
user=>You can also supply a vector of features (or an ndarray like core.matrix matrices):
(train [
[
[1.0, 2.0],
[3.0, 4.0]
]
[
[1.0, 2.0],
[3.0, 4.0]
]
]
[["y3", "y4"]
["y3", "y4"]]
"trainmodel.crfsuite")Pass a sequence of features to be tagged with a model stored in traimodel.crfsuite. Returns a
sequence of tag, probability pairs.
user=> (tag [{:feat1 2.0, :feat2 3.0} {:feat1 3.0, :feat2 4.0}] "trainmodel.crfsuite")
[
[{:tag "y1"} {:probability 0.43526113123400284}] ;; instances of type clj-crfsuite.core.Tag
[{:tag "y3"} {:probability 0.36107961034023944}]
])Copyright © 2015 - 2016 Onu Technology, Inc.
Distributed under the Apache v2 License.