280 lines
8.8 KiB
Python
280 lines
8.8 KiB
Python
# Copyright (c) Facebook, Inc. and its affiliates.
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#
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# This source code is licensed under the MIT license found in the
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# LICENSE file in the root directory of this source tree.
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import logging
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import os
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import numpy as np
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from fairseq import utils
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from fairseq.data import (
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ConcatSentencesDataset,
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Dictionary,
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IdDataset,
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NestedDictionaryDataset,
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NumelDataset,
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NumSamplesDataset,
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OffsetTokensDataset,
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PrependTokenDataset,
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RawLabelDataset,
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RightPadDataset,
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RollDataset,
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SortDataset,
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StripTokenDataset,
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data_utils,
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)
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from fairseq.data.shorten_dataset import maybe_shorten_dataset
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from fairseq.tasks import LegacyFairseqTask, register_task
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logger = logging.getLogger(__name__)
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@register_task("sentence_prediction")
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class SentencePredictionTask(LegacyFairseqTask):
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"""
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Sentence (or sentence pair) prediction (classification or regression) task.
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Args:
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dictionary (Dictionary): the dictionary for the input of the task
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"""
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@staticmethod
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def add_args(parser):
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"""Add task-specific arguments to the parser."""
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parser.add_argument("data", metavar="FILE", help="file prefix for data")
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parser.add_argument(
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"--num-classes",
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type=int,
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default=-1,
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help="number of classes or regression targets",
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)
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parser.add_argument(
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"--init-token",
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type=int,
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default=None,
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help="add token at the beginning of each batch item",
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)
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parser.add_argument(
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"--separator-token",
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type=int,
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default=None,
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help="add separator token between inputs",
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)
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parser.add_argument("--regression-target", action="store_true", default=False)
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parser.add_argument("--no-shuffle", action="store_true", default=False)
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parser.add_argument(
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"--shorten-method",
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default="none",
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choices=["none", "truncate", "random_crop"],
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help="if not none, shorten sequences that exceed --tokens-per-sample",
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)
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parser.add_argument(
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"--shorten-data-split-list",
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default="",
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help="comma-separated list of dataset splits to apply shortening to, "
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'e.g., "train,valid" (default: all dataset splits)',
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)
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parser.add_argument(
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"--add-prev-output-tokens",
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action="store_true",
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default=False,
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help="add prev_output_tokens to sample, used for encoder-decoder arch",
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)
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def __init__(self, args, data_dictionary, label_dictionary):
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super().__init__(args)
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self.dictionary = data_dictionary
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self._label_dictionary = label_dictionary
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if not hasattr(args, "max_positions"):
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self._max_positions = (
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args.max_source_positions,
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args.max_target_positions,
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)
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else:
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self._max_positions = args.max_positions
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args.tokens_per_sample = self._max_positions
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@classmethod
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def load_dictionary(cls, args, filename, source=True):
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"""Load the dictionary from the filename
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Args:
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filename (str): the filename
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"""
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dictionary = Dictionary.load(filename)
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dictionary.add_symbol("<mask>")
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return dictionary
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@classmethod
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def setup_task(cls, args, **kwargs):
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assert args.num_classes > 0, "Must set --num-classes"
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# load data dictionary
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data_dict = cls.load_dictionary(
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args,
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os.path.join(args.data, "input0", "dict.txt"),
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source=True,
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)
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logger.info("[input] dictionary: {} types".format(len(data_dict)))
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# load label dictionary
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if not args.regression_target:
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label_dict = cls.load_dictionary(
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args,
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os.path.join(args.data, "label", "dict.txt"),
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source=False,
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)
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logger.info("[label] dictionary: {} types".format(len(label_dict)))
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else:
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label_dict = data_dict
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return cls(args, data_dict, label_dict)
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def load_dataset(self, split, combine=False, **kwargs):
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"""Load a given dataset split (e.g., train, valid, test)."""
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def get_path(key, split):
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return os.path.join(self.args.data, key, split)
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def make_dataset(key, dictionary):
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split_path = get_path(key, split)
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dataset = data_utils.load_indexed_dataset(
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split_path,
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dictionary,
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self.args.dataset_impl,
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combine=combine,
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)
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return dataset
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input0 = make_dataset("input0", self.source_dictionary)
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assert input0 is not None, "could not find dataset: {}".format(
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get_path("input0", split)
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)
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input1 = make_dataset("input1", self.source_dictionary)
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if self.args.init_token is not None:
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input0 = PrependTokenDataset(input0, self.args.init_token)
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if input1 is None:
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src_tokens = input0
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else:
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if self.args.separator_token is not None:
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input1 = PrependTokenDataset(input1, self.args.separator_token)
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src_tokens = ConcatSentencesDataset(input0, input1)
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with data_utils.numpy_seed(self.args.seed):
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shuffle = np.random.permutation(len(src_tokens))
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src_tokens = maybe_shorten_dataset(
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src_tokens,
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split,
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self.args.shorten_data_split_list,
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self.args.shorten_method,
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self.max_positions(),
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self.args.seed,
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)
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dataset = {
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"id": IdDataset(),
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"net_input": {
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"src_tokens": RightPadDataset(
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src_tokens,
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pad_idx=self.source_dictionary.pad(),
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),
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"src_lengths": NumelDataset(src_tokens, reduce=False),
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},
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"nsentences": NumSamplesDataset(),
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"ntokens": NumelDataset(src_tokens, reduce=True),
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}
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if self.args.add_prev_output_tokens:
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prev_tokens_dataset = RightPadDataset(
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RollDataset(src_tokens, 1),
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pad_idx=self.dictionary.pad(),
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)
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dataset["net_input"].update(
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prev_output_tokens=prev_tokens_dataset,
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)
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if not self.args.regression_target:
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label_dataset = make_dataset("label", self.label_dictionary)
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if label_dataset is not None:
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dataset.update(
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target=OffsetTokensDataset(
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StripTokenDataset(
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label_dataset,
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id_to_strip=self.label_dictionary.eos(),
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),
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offset=-self.label_dictionary.nspecial,
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)
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)
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else:
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label_path = "{0}.label".format(get_path("label", split))
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if os.path.exists(label_path):
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def parse_regression_target(i, line):
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values = line.split()
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assert (
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len(values) == self.args.num_classes
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), f'expected num_classes={self.args.num_classes} regression target values on line {i}, found: "{line}"'
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return [float(x) for x in values]
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with open(label_path) as h:
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dataset.update(
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target=RawLabelDataset(
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[
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parse_regression_target(i, line.strip())
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for i, line in enumerate(h.readlines())
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]
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)
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)
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nested_dataset = NestedDictionaryDataset(
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dataset,
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sizes=[src_tokens.sizes],
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)
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if self.args.no_shuffle:
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dataset = nested_dataset
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else:
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dataset = SortDataset(
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nested_dataset,
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# shuffle
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sort_order=[shuffle],
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)
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logger.info("Loaded {0} with #samples: {1}".format(split, len(dataset)))
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self.datasets[split] = dataset
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return self.datasets[split]
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def build_model(self, args):
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from fairseq import models
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model = models.build_model(args, self)
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model.register_classification_head(
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getattr(args, "classification_head_name", "sentence_classification_head"),
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num_classes=self.args.num_classes,
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)
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return model
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def max_positions(self):
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return self._max_positions
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@property
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def source_dictionary(self):
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return self.dictionary
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@property
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def target_dictionary(self):
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return self.dictionary
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@property
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def label_dictionary(self):
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return self._label_dictionary
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