wiki_lingua.py

# coding=utf-8
# Copyright 2020 The HuggingFace Datasets Authors and the current dataset script contributor.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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"""WikiLingua: A benchmark dataset for multilingual abstractive summarization."""

import os
import glob
import pickle
import datasets


_CITATION = """\
@article{ladhak-wiki-2020,
  title   = {WikiLingua: A New Benchmark Dataset for Multilingual Abstractive Summarization},
  authors = {Faisal Ladhak, Esin Durmus, Claire Cardie and Kathleen McKeown},
  journal = {arXiv preprint arXiv:2010.03093},
  year    = {2020},
  url     = {https://arxiv.org/abs/2010.03093}
}
"""

_DESCRIPTION = """\
WikiLingua is a large-scale multilingual dataset for the evaluation of
crosslingual abstractive summarization systems. The dataset includes ~770k
article and summary pairs in 18 languages from WikiHow. The gold-standard
article-summary alignments across languages was done by aligning the images
that are used to describe each how-to step in an article.
"""

_HOMEPAGE = "https://github.com/esdurmus/Wikilingua"

_LICENSE = "CC BY-NC-SA 3.0"

_URL = "wikilingua_GEM_v2.tar.gz"

VERSION = datasets.Version("2.0.0")

valid_language_codes = {
    "ar",
    "cs",
    "de",
    "en",
    "es",
    "fr",
    "hi",
    "id",
    "it",
    "ja",
    "ko",
    "nl",
    "pt",
    "ru",
    "th",
    "tr",
    "vi",
    "zh",
}

valid_config_names = (
    # multilingual
    list(valid_language_codes)
    + [
        # crosslingual / bridge
        f"{src}_{tgt}"
        for src in valid_language_codes
        for tgt in valid_language_codes
        if src != tgt
    ]
    # load all multilingual / all crosslingual
    + ["multilingual", "crosslingual"]
)


class WikilinguaModes:
    MULTILINGUAL = "multilingual"  # L -> L
    CROSSLINGUAL = "crosslingual"  # L1 -> L1, L2 -> L2, L1 -> L2, L2 -> L1
    BRIDGE = "bridge"  # L -> en, en -> L, L -> L


class WikilinguaConfig(datasets.BuilderConfig):
    """BuilderConfig for WikiLingua."""

    def __init__(self, name, **kwargs):
        """
        Args:
            name (string): configuration name that indicates task setup and languages.

                1. multilingual  - <lang>
                2. crosslingual - <lang1>_<lang2>
                3. english as bridge - en_<lang>
                4. load all multilingual - multilingual
                5. load all crosslingual - crosslingual

                lang refers to the respective two-letter language code.
                note that the order of lang1/lang2 does not matter;
                for language pair (L1, L2), we load L1 <-> L2 and L1 -> L1, L2 -> L2.
        """
        if name not in valid_config_names:
            raise ValueError(
                f"Expected config name to be one of: {', '.join(valid_config_names)}"
            )

        eles = name.split("_")

        if name in (WikilinguaModes.MULTILINGUAL, WikilinguaModes.CROSSLINGUAL):
            self.mode = name
            self.source_lang = None
            self.target_lang = None
            description = f"Wikilingua summarization data ({self.mode};  all instances)"
        else:
            if len(eles) == 1:
                mode = WikilinguaModes.MULTILINGUAL
                source_lang, target_lang = name, name
            elif len(eles) == 2:
                source_lang, target_lang = eles
                if source_lang == "en" or target_lang == "en":
                    mode = WikilinguaModes.BRIDGE
                else:
                    mode = WikilinguaModes.CROSSLINGUAL
            self.source_lang = source_lang
            self.target_lang = target_lang
            self.mode = mode
            description = (
                f"Wikilingua summarisation data ({mode}; {source_lang}, {target_lang})"
            )
        self.languages = set([self.source_lang, self.target_lang])

        super().__init__(
            name=name,
            description=description,
            **kwargs,
        )


class WikiLingua(datasets.GeneratorBasedBuilder):
    """WikiLingua: A benchmark dataset for multilingual abstractive summarization."""

    BUILDER_CONFIG_CLASS = WikilinguaConfig

    BUILDER_CONFIGS = [
        WikilinguaConfig(
            name=config_name,
            version=VERSION,
        )
        for config_name in valid_config_names
    ]

    DEFAULT_CONFIG_NAME = "en"

    def _info(self):
        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=datasets.Features(
                {
                    "gem_id": datasets.Value("string"),
                    "gem_parent_id": datasets.Value("string"),
                    "source_language": datasets.Value("string"),
                    "target_language": datasets.Value("string"),
                    "source": datasets.Value("string"),
                    "target": datasets.Value("string"),
                    "references": [datasets.Value("string")],
                }
            ),
            supervised_keys=None,
            homepage=_HOMEPAGE,
            license=_LICENSE,
            citation=_CITATION,
        )

    def _split_generators(self, dl_manager):
        """Returns SplitGenerators."""

        dl_dir = dl_manager.download_and_extract(_URL)
        data_dir = os.path.join(dl_dir, "GEM_V2")

        return [
            datasets.SplitGenerator(
                name=datasets.Split.TRAIN,
                gen_kwargs={
                    "filepaths": glob.glob(
                        os.path.join(data_dir, f"wikilingua_*.train.pk")
                    )
                },
            ),
            datasets.SplitGenerator(
                name=datasets.Split.VALIDATION,
                gen_kwargs={
                    "filepaths": glob.glob(
                        os.path.join(data_dir, f"wikilingua_*lingual.val.pk")
                    )
                },
            ),
            datasets.SplitGenerator(
                name=datasets.Split.TEST,
                gen_kwargs={
                    "filepaths": glob.glob(
                        os.path.join(data_dir, f"wikilingua_*lingual.test.pk")
                    )
                },
            ),
            datasets.SplitGenerator(
                name=f"sampled_{datasets.Split.VALIDATION}",
                gen_kwargs={
                    "filepaths": glob.glob(
                        os.path.join(data_dir, f"wikilingua_*_sampled.val.pk")
                    )
                },
            ),
            datasets.SplitGenerator(
                name=f"sampled_{datasets.Split.TEST}",
                gen_kwargs={
                    "filepaths": glob.glob(
                        os.path.join(data_dir, f"wikilingua_*_sampled.test.pk")
                    )
                },
            ),
        ]

    def _generate_examples(self, filepaths):
        """Yields examples."""
        for filepath in filepaths:
            if (
                self.config.name == WikilinguaModes.MULTILINGUAL
                and WikilinguaModes.CROSSLINGUAL in filepath
            ) or (
                self.config.name == WikilinguaModes.CROSSLINGUAL
                and WikilinguaModes.MULTILINGUAL in filepath
            ):
                yield from []
            else:

                with open(filepath, "rb") as f:
                    data = pickle.load(f)

                    for d in data:
                        idx = d["id"].replace(".", "-")
                        src = d["document"].strip()
                        tgt = d["summary"].strip()
                        src_lang = d["source"]
                        tgt_lang = d["target"]

                        # if loading specific language pair, filter for those
                        if any(self.config.languages):
                            if not (
                                src_lang in self.config.languages
                                and tgt_lang in self.config.languages
                            ):
                                continue

                        # in bridge, we are inerested in L <-> en and L -> L, but not en -> en
                        if self.config.mode == WikilinguaModes.BRIDGE:
                            if src_lang == "en" and tgt_lang == "en":
                                continue

                        yield idx, {
                            "gem_id": idx,
                            "gem_parent_id": idx,
                            "source_language": src_lang,
                            "target_language": tgt_lang,
                            "source": src,
                            "target": tgt,
                            "references": [tgt],
                        }