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A parser for natural language based on combinatory categorial grammar

Project description

depccg v1

UPDATE 2019/6/7
The datasets and codes for my ACL2019 paper (Automatic Generation of High Quality CCGbanks for Parser Domain Adaptation) are available at the following repo!: https://github.com/masashi-y/ud2ccg

Codebase for A* CCG Parsing with a Supertag and Dependency Factored Model

Requirements

  • Python >= 3.6.0
  • A C++ compiler supporting C++11 standard (in case of gcc, must be >= 4.8)
  • OpenMP (optional, for efficient batched parsing)

Installation

Using pip:

➜ pip install cython numpy depccg

If OpenMP is available in your environment, you can use it for more efficient parsing:

USE_OPENMP=1 pip install cython numpy depccg

Usage

Using a pretrained English parser

Better performing ELMo model is also available now.

The best performing model in the paper trained on tri-training is available:

➜ depccg_en download

It can be downloaded directly here (189M).

echo "this is a test sentence ." | depccg_en
ID=1, Prob=-0.0006299018859863281
(<T S[dcl] 0 2> (<T S[dcl] 0 2> (<L NP XX XX this NP>) (<T S[dcl]\NP 0 2> (<L (S[dcl]\NP)/NP XX XX is (S[dcl]\NP)/NP>) (<T NP 0 2> (<L NP[nb]/N XX XX a NP[nb]/N>) (<T N 0 2> (<L N/N XX XX test N/N>) (<L N XX XX sentence N>) ) ) ) ) (<L . XX XX . .>) )

You can specify output format (see below).

echo "this is a test sentence ." | depccg_en --format deriv
ID=1, Prob=-0.0006299018859863281
 this        is           a      test  sentence  .
  NP   (S[dcl]\NP)/NP  NP[nb]/N  N/N      N      .
                                ---------------->
                                       N
                      -------------------------->
                                  NP
      ------------------------------------------>
                      S[dcl]\NP
------------------------------------------------<
                     S[dcl]
---------------------------------------------------<rp>
                      S[dcl]

By default, the input is expected to be pre-tokenized. If you want to process untokenized sentences, you can pass --tokenize option.

The POS and NER tags in the output are filled with XX by default. You can replace them with ones predicted using SpaCy:

➜ pip install spacy
➜ python -m spacy download en
➜ echo "this is a test sentence ." | depccg_en --annotator spacy
ID=1, Prob=-0.0006299018859863281
(<T S[dcl] 0 2> (<T S[dcl] 0 2> (<L NP DT DT this NP>) (<T S[dcl]\NP 0 2> (<L (S[dcl]\NP)/NP VBZ VBZ is (S[dcl]\NP)/NP>) (<T NP 0 2> (<L NP[nb]/N DT DT a NP[nb]/N>) (<T N 0 2> (<L N/N NN NN test N/N>) (<L N NN NN sentence N>) ) ) ) ) (<L . . . . .>) )

The parser uses a SpaCy's model symbolic-linked to en (it loads a model by spacy('en')).

Orelse, you can use POS/NER taggers implemented in C&C, which may be useful in some sorts of parsing experiments:

export CANDC=/path/to/candc
➜ echo "this is a test sentence ." | depccg_en --annotator candc
ID=1, Prob=-0.0006299018859863281
(<T S[dcl] 0 2> (<T S[dcl] 0 2> (<L NP DT DT this NP>) (<T S[dcl]\NP 0 2> (<L (S[dcl]\NP)/NP VBZ VBZ is (S[dcl]\NP)/NP>) (<T NP 0 2> (<L NP[nb]/N DT DT a NP[nb]/N>) (<T N 0 2> (<L N/N NN NN test N/N>) (<L N NN NN sentence N>) ) ) ) ) (<L . . . . .>) )

By default, depccg expects the POS and NER models are placed in $CANDC/models/pos and $CANDC/models/ner, but you can explicitly specify them by setting CANDC_MODEL_POS and CANDC_MODEL_NER environmental variables.

It is also possible to obtain logical formulas using ccg2lambda's semantic parsing algorithm.

echo "This is a test sentence ." | depccg_en --format ccg2lambda --annotator spacy
ID=0 log probability=-0.0006299018859863281
exists x.(_this(x) & exists z1.(_sentence(z1) & _test(z1) & (x = z1)))

The best performing ELMo model

In accordance with many other reported results, depccg obtains the improved performance by using contextualized word embeddings (ELMo; Peters et al., 2018).

The ELMo model replaces affix embeddings in (Yoshikawa et al., 2017) with ELMo, resulting in 1124 dimensional input embeddings (ELMo + GloVe). It is trained on CCGbank and the tri-training silver dataset.

Unlabeled F1 Labeled F1
(Yoshikawa et al., 2017) 94.0 88.8
+ELMo 94.98 90.51

Please download the model from the following link.

To use the model, install allennlp:

➜ pip install allennlp

and then,

echo "this is a test sentence ." | depccg_en --model lstm_parser_elmo_finetune.tar.gz

Using a GPU (by --gpu option) is recommended if possible.

Using a pretrained Japanese parser

The best performing model is available by:

➜ depccg_ja download

It can be downloaded directly here (56M).

The Japanese parser depends on Janome for the tokenization. Please install it by:

➜ pip install janome

The parser provides the almost same interface as with the English one, with slight differences including the default output format, which is now one compatible with the Japanese CCGbank:

echo "これはテストの文です。" | depccg_ja
ID=1, Prob=-53.98793411254883
{< S[mod=nm,form=base,fin=t] {< S[mod=nm,form=base,fin=f] {< NP[case=nc,mod=nm,fin=f] {NP[case=nc,mod=nm,fin=f] これ/これ/**} {NP[case=nc,mod=nm,fin=f]\NP[case=nc,mod=nm,fin=f] は/は/**}} {< S[mod=nm,form=base,fin=f]\NP[case=nc,mod=nm,fin=f] {< NP[case=nc,mod=nm,fin=f] {< NP[case=nc,mod=nm,fin=f] {NP[case=nc,mod=nm,fin=f] テスト/テスト/**} {NP[case=nc,mod=nm,fin=f]\NP[case=nc,mod=nm,fin=f] の/の/**}} {NP[case=nc,mod=nm,fin=f]\NP[case=nc,mod=nm,fin=f] 文/文/**}} {(S[mod=nm,form=base,fin=f]\NP[case=nc,mod=nm,fin=f])\NP[case=nc,mod=nm,fin=f] です/です/**}}} {S[mod=nm,form=base,fin=t]\S[mod=nm,form=base,fin=f] 。/。/**}}

You can pass pre-tokenized sentences as well:

echo "これ は テスト の 文 です 。" | depccg_ja --pre-tokenized
ID=1, Prob=-53.98793411254883
{< S[mod=nm,form=base,fin=t] {< S[mod=nm,form=base,fin=f] {< NP[case=nc,mod=nm,fin=f] {NP[case=nc,mod=nm,fin=f] これ/これ/**} {NP[case=nc,mod=nm,fin=f]\NP[case=nc,mod=nm,fin=f] は/は/**}} {< S[mod=nm,form=base,fin=f]\NP[case=nc,mod=nm,fin=f] {< NP[case=nc,mod=nm,fin=f] {< NP[case=nc,mod=nm,fin=f] {NP[case=nc,mod=nm,fin=f] テスト/テスト/**} {NP[case=nc,mod=nm,fin=f]\NP[case=nc,mod=nm,fin=f] の/の/**}} {NP[case=nc,mod=nm,fin=f]\NP[case=nc,mod=nm,fin=f] 文/文/**}} {(S[mod=nm,form=base,fin=f]\NP[case=nc,mod=nm,fin=f])\NP[case=nc,mod=nm,fin=f] です/です/**}}} {S[mod=nm,form=base,fin=t]\S[mod=nm,form=base,fin=f] 。/。/**}}

Available output formats

  • auto - the most standard format following AUTO format in the English CCGbank
  • deriv - visualized derivations in ASCII art
  • xml - XML format compatible with C&C's XML format (only for English parsing)
  • conll - CoNLL format
  • html - visualized trees in MathML
  • prolog - Prolog-like format
  • jigg_xml - XML format compatible with Jigg
  • ptb - Penn Treebank-style format
  • ccg2lambda - logical formula converted from a derivation using ccg2lambda
  • jigg_xml_ccg2lambda - jigg_xml format with ccg2lambda logical formula inserted
  • json - JSON format
  • ja - a format adopted in Japanese CCGbank (only for Japanese)

Programatic Usage

from depccg.parser import EnglishCCGParser
from pathlib import Path

# Available keyword arguments in initializing a CCG parser
# Please refer to the following paper for category dictionary, seen rules, pruning etc.
# "A* CCG Parsing with a Supertag-factored Model", Lewis and Steedman, 2014
kwargs = dict(
    # A list of binary rules 
    # By default: depccg.combinator.en_default_binary_rules
    binary_rules=None,
    # Penalize an application of a unary rule by adding this value (negative log probability)
    unary_penalty=0.1,
    # Prune supertags with low probabilities using this value
    beta=0.00001,
    # Set False if not prune
    use_beta=True,
    # Use category dictionary
    use_category_dict=True,
    # Use seen rules
    use_seen_rules=True,
    # This also used to prune supertags
    pruning_size=50,
    # Nbest outputs
    nbest=1,
    # Limit categories that can appear at the root of a CCG tree
    # By default: S[dcl], S[wq], S[q], S[qem], NP.
    possible_root_cats=None,
    # Give up parsing long sentences
    max_length=250,
    # Give up parsing if it runs too many steps
    max_steps=100000,
    # You can specify a GPU
    gpu=-1
)

# Initialize a parser from a model directory
model = "/path/to/model/directory"
parser = EnglishCCGParser.from_dir(
    model,
    load_tagger=True, # Load supertagging model
    **kwargs)

model = Path("/path/to/model/directory")
parser = EnglishCCGParser.from_files(
    unary_rules=model / 'unary_rules.txt',
    category_dict=model / 'cat_dict.txt',
    seen_rules=model / 'seen_rules.txt',
    tagger_model=model / 'tagger_model',
    **kwargs)

# If you don't like to keep separate files,
# wget http://cl.naist.jp/~masashi-y/resources/depccg/config.json
model = Path("/path/to/model/directory")
parser = EnglishCCGParser.from_json(
    model / 'config.json',
    tagger_model=model / 'tagger_model',
    **kwargs)

sents = [
  "This is a test sentence .",
  "This is second ."
]

results = parser.parse_doc(sents)
for nbests in results:
    for tree, log_prob in nbests:
        print(tree.deriv)

For Japanese CCG parsing, use depccg.parser.JapaneseCCGParser, which has the exactly same interface. Note that the Japanese parser accepts pre-tokenized sentences as input.

Train your own English supertagging model

You can use my allennlp-based supertagger and extend it.

To train a supertagger, prepare the English CCGbank and download vocab:

➜ cat ccgbank/data/AUTO/{0[2-9],1[0-9],20,21}/* > wsj_02-21.auto
➜ cat ccgbank/data/AUTO/00/* > wsj_00.auto
➜ wget http://cl.naist.jp/~masashi-y/resources/depccg/vocabulary.tar.gz
➜ tar xvf vocabulary.tar.gz

then,

vocab=vocabulary train_data=wsj_02-21.auto test_data=wsj_00.auto gpu=0 \
  encoder_type=lstm token_embedding_type=char \
  allennlp train --include-package depccg.models.my_allennlp --serialization-dir results supertagger.jsonnet

The training configs are passed either through environmental variables or directly writing to jsonnet config files, which are available in supertagger.jsonnet or supertagger_tritrain.jsonnet. The latter is a config file for using tri-training silver data (309M) constructed in (Yoshikawa et al., 2017), on top of the English CCGbank.

To use the trained supertagger,

echo "this is a test sentence ."  | depccg_en --model results/model.tar.gz

or alternatively,

echo '{"sentence": "this is a test sentence ."}' > input.jsonl
➜ allennlp predict results/model.tar.gz --include-package depccg.models.my_allennlp --output-file weights.json input.jsonl
➜ cat weights.json | depccg_en --input-format json

where weights.json contains probabilities used in the parser (p_tag and p_dep).

Evaluation in terms of predicate-argument dependencies

The standard CCG parsing evaluation can be performed with the following script:

➜ cat ccgbank/data/PARG/00/* > wsj_00.parg
➜ export CANDC=/path/to/candc
➜ python -m depccg.tools.evaluate wsj_00.parg wsj_00.predicted.auto

Currently, the script is dependent on C&C's generate program, which is only available by compiling the C&C program from the source.

Miscellaneous

Diff tool

In error analysis, you must want to see diffs between trees in an intuitive way. depccg.tools.diff does exactly this:

➜ python -m depccg.tools.diff file1.auto file2.auto > diff.html

which outputs:

show diffs between trees

where trees in the same lines of the files are compared and the diffs are marked in color.

Citation

If you make use of this software, please cite the following:

@inproceedings{yoshikawa:2017acl,
  author={Yoshikawa, Masashi and Noji, Hiroshi and Matsumoto, Yuji},
  title={A* CCG Parsing with a Supertag and Dependency Factored Model},
  booktitle={Proceedings of the 55th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)},
  publisher={Association for Computational Linguistics},
  year={2017},
  pages={277--287},
  location={Vancouver, Canada},
  doi={10.18653/v1/P17-1026},
  url={http://aclweb.org/anthology/P17-1026}
}

Licence

MIT Licence

Contact

For questions and usage issues, please contact yoshikawa.masashi.yh8@is.naist.jp .

Acknowledgement

In creating the parser, I owe very much to:

  • EasyCCG: from which I learned everything
  • NLTK: for nice pretty printing for parse derivation

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