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import logging |
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import numpy as np |
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import torch |
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from fairseq.data import Dictionary, FairseqDataset |
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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("dummy_mt") |
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class DummyMTTask(LegacyFairseqTask): |
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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("--dict-size", default=49996, type=int) |
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parser.add_argument("--dataset-size", default=100000, type=int) |
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parser.add_argument("--src-len", default=30, type=int) |
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parser.add_argument("--tgt-len", default=30, type=int) |
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def __init__(self, args, dictionary): |
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super().__init__(args) |
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self.dictionary = dictionary |
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self.seed = args.seed |
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dictionary.pad_to_multiple_(8) |
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self.dummy_src = torch.arange(args.src_len + 1) + dictionary.pad() + 1 |
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self.dummy_tgt = torch.arange(args.tgt_len + 1) + dictionary.pad() + 1 |
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@classmethod |
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def setup_task(cls, args, **kwargs): |
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"""Setup the task. """ |
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dictionary = Dictionary() |
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for i in range(args.dict_size): |
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dictionary.add_symbol("word{}".format(i)) |
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logger.info("dictionary: {} types".format(len(dictionary))) |
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args.max_source_positions = args.src_len + dictionary.pad() + 2 |
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args.max_target_positions = args.tgt_len + dictionary.pad() + 2 |
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return cls(args, dictionary) |
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def load_dataset(self, split, epoch=1, combine=False, **kwargs): |
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"""Load a given dataset split. |
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Args: |
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split (str): name of the split (e.g., train, valid, test) |
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""" |
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item_size = max(self.args.src_len, self.args.tgt_len) |
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if self.args.batch_size is not None: |
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bsz = self.args.batch_size |
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else: |
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bsz = max(1, self.args.max_tokens // item_size) |
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tgt = torch.stack([self.dummy_tgt for _ in range(bsz)]) |
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self.datasets[split] = DummyDataset( |
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{ |
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"id": 1, |
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"net_input": { |
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"src_tokens": torch.stack([self.dummy_src for _ in range(bsz)]), |
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"src_lengths": torch.full( |
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(bsz,), self.args.src_len, dtype=torch.long |
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), |
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"prev_output_tokens": tgt.clone(), |
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}, |
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"target": tgt, |
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"nsentences": bsz, |
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"ntokens": bsz * self.args.tgt_len, |
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}, |
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num_items=self.args.dataset_size, |
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item_size=item_size, |
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) |
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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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class DummyDataset(FairseqDataset): |
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def __init__(self, batch, num_items, item_size): |
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super().__init__() |
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self.batch = batch |
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self.num_items = num_items |
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self.item_size = item_size |
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def __getitem__(self, index): |
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return index |
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def __len__(self): |
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return self.num_items |
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def collater(self, samples): |
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return self.batch |
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@property |
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def sizes(self): |
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return np.array([self.item_size] * self.num_items) |
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def num_tokens(self, index): |
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return self.item_size |
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def size(self, index): |
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return self.item_size |
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def ordered_indices(self): |
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return np.arange(self.num_items) |
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@property |
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def supports_prefetch(self): |
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return False |
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