File size: 13,524 Bytes
650c5f6
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.

import json
import os
import tempfile

import numpy as np
import torch
import torch.nn.functional as F
from fairseq import utils
from fairseq.data import (
    Dictionary,
    IdDataset,
    ListDataset,
    NestedDictionaryDataset,
    NumelDataset,
    NumSamplesDataset,
    PadDataset,
    SortDataset,
    data_utils,
    encoders,
)
from fairseq.tasks import LegacyFairseqTask, register_task

from . import wsc_utils


@register_task("wsc")
class WSCTask(LegacyFairseqTask):
    """Task to finetune RoBERTa for Winograd Schemas."""

    @staticmethod
    def add_args(parser):
        """Add task-specific arguments to the parser."""
        parser.add_argument(
            "data", metavar="DIR", help="path to data directory; we load <split>.jsonl"
        )
        parser.add_argument(
            "--init-token",
            type=int,
            default=None,
            help="add token at the beginning of each batch item",
        )

    def __init__(self, args, vocab):
        super().__init__(args)
        self.vocab = vocab
        self.mask = vocab.add_symbol("<mask>")

        self.bpe = encoders.build_bpe(args)
        self.tokenizer = encoders.build_tokenizer(args)

        # hack to handle GPT-2 BPE, which includes leading spaces
        if args.bpe == "gpt2":
            self.leading_space = True
            self.trailing_space = False
        else:
            self.leading_space = False
            self.trailing_space = True

    @classmethod
    def load_dictionary(cls, filename):
        """Load the dictionary from the filename

        Args:
            filename (str): the filename
        """
        dictionary = Dictionary.load(filename)
        dictionary.add_symbol("<mask>")
        return dictionary

    @classmethod
    def setup_task(cls, args, **kwargs):
        assert args.criterion == "wsc", "Must set --criterion=wsc"

        # load data and label dictionaries
        vocab = cls.load_dictionary(os.path.join(args.data, "dict.txt"))
        print("| dictionary: {} types".format(len(vocab)))

        return cls(args, vocab)

    def binarize(self, s: str, append_eos: bool = False):
        if self.tokenizer is not None:
            s = self.tokenizer.encode(s)
        if self.bpe is not None:
            s = self.bpe.encode(s)
        tokens = self.vocab.encode_line(
            s,
            append_eos=append_eos,
            add_if_not_exist=False,
        ).long()
        if self.args.init_token is not None:
            tokens = torch.cat([tokens.new([self.args.init_token]), tokens])
        return tokens

    def binarize_with_mask(self, txt, prefix, suffix, leading_space, trailing_space):
        toks = self.binarize(
            prefix + leading_space + txt + trailing_space + suffix,
            append_eos=True,
        )
        mask = torch.zeros_like(toks, dtype=torch.bool)
        mask_start = len(self.binarize(prefix))
        mask_size = len(self.binarize(leading_space + txt))
        mask[mask_start : mask_start + mask_size] = 1
        return toks, mask

    def load_dataset(
        self, split, epoch=1, combine=False, data_path=None, return_only=False, **kwargs
    ):
        """Load a given dataset split.

        Args:
            split (str): name of the split (e.g., train, valid, test)
        """
        if data_path is None:
            data_path = os.path.join(self.args.data, split + ".jsonl")
        if not os.path.exists(data_path):
            raise FileNotFoundError("Cannot find data: {}".format(data_path))

        query_tokens = []
        query_masks = []
        query_lengths = []
        candidate_tokens = []
        candidate_masks = []
        candidate_lengths = []
        labels = []

        for sentence, pronoun_span, query, label in wsc_utils.jsonl_iterator(data_path):
            prefix = sentence[: pronoun_span.start].text
            suffix = sentence[pronoun_span.end :].text_with_ws

            # spaCy spans include trailing spaces, but we need to know about
            # leading spaces for the GPT-2 BPE
            leading_space = (
                " " if sentence[: pronoun_span.start].text_with_ws.endswith(" ") else ""
            )
            trailing_space = " " if pronoun_span.text_with_ws.endswith(" ") else ""

            # get noun phrases, excluding pronouns and anything overlapping with the query
            cand_spans = wsc_utils.filter_noun_chunks(
                wsc_utils.extended_noun_chunks(sentence),
                exclude_pronouns=True,
                exclude_query=query,
                exact_match=False,
            )

            if query is not None:
                query_toks, query_mask = self.binarize_with_mask(
                    query, prefix, suffix, leading_space, trailing_space
                )
                query_len = len(query_toks)
            else:
                query_toks, query_mask, query_len = None, None, 0

            query_tokens.append(query_toks)
            query_masks.append(query_mask)
            query_lengths.append(query_len)

            cand_toks, cand_masks = [], []
            for cand_span in cand_spans:
                toks, mask = self.binarize_with_mask(
                    cand_span.text,
                    prefix,
                    suffix,
                    leading_space,
                    trailing_space,
                )
                cand_toks.append(toks)
                cand_masks.append(mask)

            # collate candidates
            cand_toks = data_utils.collate_tokens(cand_toks, pad_idx=self.vocab.pad())
            cand_masks = data_utils.collate_tokens(cand_masks, pad_idx=0)
            assert cand_toks.size() == cand_masks.size()

            candidate_tokens.append(cand_toks)
            candidate_masks.append(cand_masks)
            candidate_lengths.append(cand_toks.size(1))

            labels.append(label)

        query_lengths = np.array(query_lengths)
        query_tokens = ListDataset(query_tokens, query_lengths)
        query_masks = ListDataset(query_masks, query_lengths)

        candidate_lengths = np.array(candidate_lengths)
        candidate_tokens = ListDataset(candidate_tokens, candidate_lengths)
        candidate_masks = ListDataset(candidate_masks, candidate_lengths)

        labels = ListDataset(labels, [1] * len(labels))

        dataset = {
            "id": IdDataset(),
            "query_tokens": query_tokens,
            "query_masks": query_masks,
            "candidate_tokens": candidate_tokens,
            "candidate_masks": candidate_masks,
            "labels": labels,
            "nsentences": NumSamplesDataset(),
            "ntokens": NumelDataset(query_tokens, reduce=True),
        }

        nested_dataset = NestedDictionaryDataset(
            dataset,
            sizes=[query_lengths],
        )

        with data_utils.numpy_seed(self.args.seed):
            shuffle = np.random.permutation(len(query_tokens))
        dataset = SortDataset(
            nested_dataset,
            # shuffle
            sort_order=[shuffle],
        )

        if return_only:
            return dataset

        self.datasets[split] = dataset
        return self.datasets[split]

    def build_dataset_for_inference(self, sample_json):
        with tempfile.NamedTemporaryFile(buffering=0) as h:
            h.write((json.dumps(sample_json) + "\n").encode("utf-8"))
            dataset = self.load_dataset(
                "disambiguate_pronoun",
                data_path=h.name,
                return_only=True,
            )
        return dataset

    def disambiguate_pronoun(self, model, sentence, use_cuda=False):
        sample_json = wsc_utils.convert_sentence_to_json(sentence)
        dataset = self.build_dataset_for_inference(sample_json)
        sample = dataset.collater([dataset[0]])
        if use_cuda:
            sample = utils.move_to_cuda(sample)

        def get_masked_input(tokens, mask):
            masked_tokens = tokens.clone()
            masked_tokens[mask.bool()] = self.mask
            return masked_tokens

        def get_lprobs(tokens, mask):
            logits, _ = model(src_tokens=get_masked_input(tokens, mask))
            lprobs = F.log_softmax(logits, dim=-1, dtype=torch.float)
            scores = lprobs.gather(2, tokens.unsqueeze(-1)).squeeze(-1)
            mask = mask.type_as(scores)
            scores = (scores * mask).sum(dim=-1) / mask.sum(dim=-1)
            return scores

        cand_lprobs = get_lprobs(
            sample["candidate_tokens"][0],
            sample["candidate_masks"][0],
        )
        if sample["query_tokens"][0] is not None:
            query_lprobs = get_lprobs(
                sample["query_tokens"][0].unsqueeze(0),
                sample["query_masks"][0].unsqueeze(0),
            )
            return (query_lprobs >= cand_lprobs).all().item() == 1
        else:
            best_idx = cand_lprobs.argmax().item()
            full_cand = sample["candidate_tokens"][0][best_idx]
            mask = sample["candidate_masks"][0][best_idx]
            toks = full_cand[mask.bool()]
            return self.bpe.decode(self.source_dictionary.string(toks)).strip()

    @property
    def source_dictionary(self):
        return self.vocab

    @property
    def target_dictionary(self):
        return self.vocab


@register_task("winogrande")
class WinograndeTask(WSCTask):
    """
    Task for WinoGrande dataset. Efficient implementation for Winograd schema
    tasks with exactly two candidates, one of which is correct.
    """

    @classmethod
    def setup_task(cls, args, **kwargs):
        assert args.criterion == "winogrande", "Must set --criterion=winogrande"

        # load data and label dictionaries
        vocab = cls.load_dictionary(os.path.join(args.data, "dict.txt"))
        print("| dictionary: {} types".format(len(vocab)))

        return cls(args, vocab)

    def load_dataset(
        self, split, epoch=1, combine=False, data_path=None, return_only=False, **kwargs
    ):
        """Load a given dataset split.

        Args:
            split (str): name of the split (e.g., train, valid, test)
        """
        if data_path is None:
            data_path = os.path.join(self.args.data, split + ".jsonl")
        if not os.path.exists(data_path):
            raise FileNotFoundError("Cannot find data: {}".format(data_path))

        query_tokens = []
        query_masks = []
        query_lengths = []
        candidate_tokens = []
        candidate_masks = []
        candidate_lengths = []

        itr = wsc_utils.winogrande_jsonl_iterator(data_path, eval=(split == "test"))

        for sample in itr:
            sentence, pronoun_span, query, cand_text = sample
            prefix = sentence[: pronoun_span[0]].rstrip()
            suffix = sentence[pronoun_span[1] :]

            leading_space = " " if sentence[: pronoun_span[0]].endswith(" ") else ""
            trailing_space = ""

            if query is not None:
                query_toks, query_mask = self.binarize_with_mask(
                    query,
                    prefix,
                    suffix,
                    leading_space,
                    trailing_space,
                )
                query_len = len(query_toks)
            else:
                query_toks, query_mask, query_len = None, None, 0

            query_tokens.append(query_toks)
            query_masks.append(query_mask)
            query_lengths.append(query_len)

            cand_toks, cand_mask = self.binarize_with_mask(
                cand_text,
                prefix,
                suffix,
                leading_space,
                trailing_space,
            )

            candidate_tokens.append(cand_toks)
            candidate_masks.append(cand_mask)
            candidate_lengths.append(cand_toks.size(0))

        query_lengths = np.array(query_lengths)

        def get_pad_dataset_fn(tokens, length, pad_idx):
            return PadDataset(
                ListDataset(tokens, length),
                pad_idx=pad_idx,
                left_pad=False,
            )

        query_tokens = get_pad_dataset_fn(query_tokens, query_lengths, self.vocab.pad())
        query_masks = get_pad_dataset_fn(query_masks, query_lengths, 0)

        candidate_lengths = np.array(candidate_lengths)
        candidate_tokens = get_pad_dataset_fn(
            candidate_tokens, candidate_lengths, self.vocab.pad()
        )
        candidate_masks = get_pad_dataset_fn(candidate_masks, candidate_lengths, 0)

        dataset = {
            "id": IdDataset(),
            "query_tokens": query_tokens,
            "query_masks": query_masks,
            "candidate_tokens": candidate_tokens,
            "candidate_masks": candidate_masks,
            "nsentences": NumSamplesDataset(),
            "ntokens": NumelDataset(query_tokens, reduce=True),
        }

        nested_dataset = NestedDictionaryDataset(
            dataset,
            sizes=[query_lengths],
        )

        with data_utils.numpy_seed(self.args.seed):
            shuffle = np.random.permutation(len(query_tokens))
        dataset = SortDataset(
            nested_dataset,
            # shuffle
            sort_order=[shuffle],
        )

        if return_only:
            return dataset

        self.datasets[split] = dataset
        return self.datasets[split]