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|
- # Copyright (c) 2017-present, Facebook, Inc.
- # All rights reserved.
- #
- # This source code is licensed under the license found in the LICENSE file in
- # the root directory of this source tree. An additional grant of patent rights
- # can be found in the PATENTS file in the same directory.
- import contextlib
- import itertools
- import glob
- import math
- import numbers
- import numpy as np
- import os
- import torch
- from torch.autograd import Variable
- import torch.utils.data
- from fairseq.dictionary import Dictionary
- from fairseq.indexed_dataset import IndexedDataset, IndexedInMemoryDataset, IndexedRawTextDataset
- def has_binary_files(data_dir, splits):
- for split in splits:
- if len(glob.glob(os.path.join(data_dir, '{}.*-*.*.bin'.format(split)))) < 2:
- return False
- return True
- def infer_language_pair(path, splits):
- """Infer language pair from filename: <split>.<lang1>-<lang2>.(...).idx"""
- src, dst = None, None
- for filename in os.listdir(path):
- parts = filename.split('.')
- for split in splits:
- if parts[0] == split and parts[-1] == 'idx':
- src, dst = parts[1].split('-')
- break
- return src, dst
- def load_dictionaries(path, src_lang, dst_lang):
- """Load dictionaries for a given language pair."""
- src_dict = Dictionary.load(os.path.join(path, 'dict.{}.txt'.format(src_lang)))
- dst_dict = Dictionary.load(os.path.join(path, 'dict.{}.txt'.format(dst_lang)))
- return src_dict, dst_dict
- def load_dataset(path, load_splits, src=None, dst=None):
- """Loads specified data splits (e.g., test, train or valid) from the
- specified folder and check that files exist."""
- if src is None and dst is None:
- # find language pair automatically
- src, dst = infer_language_pair(path, load_splits)
- assert src is not None and dst is not None, 'Source and target languages should be provided'
- src_dict, dst_dict = load_dictionaries(path, src, dst)
- dataset = LanguageDatasets(src, dst, src_dict, dst_dict)
- # Load dataset from binary files
- def all_splits_exist(src, dst, lang):
- for split in load_splits:
- filename = '{0}.{1}-{2}.{3}.idx'.format(split, src, dst, lang)
- if not os.path.exists(os.path.join(path, filename)):
- return False
- return True
- # infer langcode
- if all_splits_exist(src, dst, src):
- langcode = '{}-{}'.format(src, dst)
- elif all_splits_exist(dst, src, src):
- langcode = '{}-{}'.format(dst, src)
- else:
- raise Exception('Dataset cannot be loaded from path: ' + path)
- def fmt_path(fmt, *args):
- return os.path.join(path, fmt.format(*args))
- for split in load_splits:
- for k in itertools.count():
- prefix = "{}{}".format(split, k if k > 0 else '')
- src_path = fmt_path('{}.{}.{}', prefix, langcode, src)
- dst_path = fmt_path('{}.{}.{}', prefix, langcode, dst)
- if not IndexedInMemoryDataset.exists(src_path):
- break
- target_dataset = None
- if IndexedInMemoryDataset.exists(dst_path):
- target_dataset = IndexedInMemoryDataset(dst_path)
- dataset.splits[prefix] = LanguagePairDataset(
- IndexedInMemoryDataset(src_path),
- target_dataset,
- pad_idx=dataset.src_dict.pad(),
- eos_idx=dataset.src_dict.eos(),
- )
- return dataset
- def load_raw_text_dataset(path, load_splits, src=None, dst=None):
- """Loads specified data splits (e.g., test, train or valid) from raw text
- files in the specified folder."""
- if src is None and dst is None:
- # find language pair automatically
- src, dst = infer_language_pair(path, load_splits)
- assert src is not None and dst is not None, 'Source and target languages should be provided'
- src_dict, dst_dict = load_dictionaries(path, src, dst)
- dataset = LanguageDatasets(src, dst, src_dict, dst_dict)
- # Load dataset from raw text files
- for split in load_splits:
- src_path = os.path.join(path, '{}.{}'.format(split, src))
- dst_path = os.path.join(path, '{}.{}'.format(split, dst))
- dataset.splits[split] = LanguagePairDataset(
- IndexedRawTextDataset(src_path, src_dict),
- IndexedRawTextDataset(dst_path, dst_dict),
- pad_idx=dataset.src_dict.pad(),
- eos_idx=dataset.src_dict.eos(),
- )
- return dataset
- class LanguageDatasets(object):
- def __init__(self, src, dst, src_dict, dst_dict):
- self.src = src
- self.dst = dst
- self.src_dict = src_dict
- self.dst_dict = dst_dict
- self.splits = {}
- assert self.src_dict.pad() == self.dst_dict.pad()
- assert self.src_dict.eos() == self.dst_dict.eos()
- assert self.src_dict.unk() == self.dst_dict.unk()
- def train_dataloader_generator(
- self, split, max_tokens=None, max_sentences=None,
- max_positions=(1024, 1024), seed=None, sample_without_replacement=0,
- shard_id=0, num_shards=1
- ):
- dataset = self.splits[split]
- with numpy_seed(seed):
- batches = uneven_batches_by_size(
- dataset.src, dataset.dst, max_tokens=max_tokens,
- max_sentences=max_sentences, max_positions=max_positions,
- # FP16: during training keep the batch size a multiple of 8
- required_batch_size_multiple=8,
- )
- frozen_batches = tuple(batches) # freeze
- def dataloader(b):
- b = mask_batches(b, shard_id=shard_id, num_shards=num_shards) # shard dataset
- return torch.utils.data.DataLoader(dataset, collate_fn=dataset.collater, batch_sampler=b)
- for epoch in itertools.count(1):
- # set seed based on the seed and epoch number so that we get
- # reproducible results when resuming from checkpoints
- with numpy_seed(seed + epoch):
- batches = list(frozen_batches) # copy
- np.random.shuffle(batches)
- if sample_without_replacement > 0:
- # emit sub-epoch dataloaders
- while len(batches) >= sample_without_replacement:
- sampled_batches = batches[:sample_without_replacement]
- remaining_batches = batches[sample_without_replacement:]
- yield dataloader(sampled_batches)
- batches = remaining_batches
- if len(batches) > 0:
- yield dataloader(batches)
- else:
- # emit full dataloader
- yield dataloader(batches)
- def eval_dataloader(self, split, num_workers=0, max_tokens=None,
- max_sentences=None, max_positions=(1024, 1024),
- skip_invalid_size_inputs_valid_test=False,
- descending=False, shard_id=0, num_shards=1):
- dataset = self.splits[split]
- batch_sampler = batches_by_size(
- dataset.src, dataset.dst, max_tokens, max_sentences,
- max_positions=max_positions,
- ignore_invalid_inputs=skip_invalid_size_inputs_valid_test,
- descending=descending,
- allow_different_src_lens=True)
- batch_sampler = mask_batches(batch_sampler, shard_id=shard_id, num_shards=num_shards)
- return torch.utils.data.DataLoader(
- dataset, num_workers=num_workers, collate_fn=dataset.collater,
- batch_sampler=batch_sampler)
- class sharded_iterator(object):
- def __init__(self, itr, num_shards, shard_id):
- assert shard_id >= 0 and shard_id < num_shards
- self.itr = itr
- self.num_shards = num_shards
- self.shard_id = shard_id
- def __len__(self):
- return len(self.itr)
- def __iter__(self):
- for i, v in enumerate(self.itr):
- if i % self.num_shards == self.shard_id:
- yield v
- class LanguagePairDataset(torch.utils.data.Dataset):
- # padding constants
- LEFT_PAD_SOURCE = True
- LEFT_PAD_TARGET = False
- def __init__(self, src, dst, pad_idx, eos_idx):
- self.src = src
- self.dst = dst
- self.pad_idx = pad_idx
- self.eos_idx = eos_idx
- def __getitem__(self, i):
- # subtract 1 for 0-based indexing
- source = self.src[i].long() - 1
- res = {'id': i, 'source': source}
- if self.dst:
- res['target'] = self.dst[i].long() - 1
- return res
- def __len__(self):
- return len(self.src)
- def collater(self, samples):
- return LanguagePairDataset.collate(samples, self.pad_idx, self.eos_idx, self.dst is not None)
- @staticmethod
- def collate(samples, pad_idx, eos_idx, has_target=True):
- if len(samples) == 0:
- return {}
- def merge(key, left_pad, move_eos_to_beginning=False):
- return LanguagePairDataset.collate_tokens(
- [s[key] for s in samples],
- pad_idx, eos_idx, left_pad, move_eos_to_beginning,
- )
- id = torch.LongTensor([s['id'] for s in samples])
- src_tokens = merge('source', left_pad=LanguagePairDataset.LEFT_PAD_SOURCE)
- # sort by descending source length
- src_lengths = torch.LongTensor([s['source'].numel() for s in samples])
- src_lengths, sort_order = src_lengths.sort(descending=True)
- id = id.index_select(0, sort_order)
- src_tokens = src_tokens.index_select(0, sort_order)
- prev_output_tokens = None
- target = None
- ntokens = None
- if has_target:
- target = merge('target', left_pad=LanguagePairDataset.LEFT_PAD_TARGET)
- # we create a shifted version of targets for feeding the
- # previous output token(s) into the next decoder step
- prev_output_tokens = merge(
- 'target',
- left_pad=LanguagePairDataset.LEFT_PAD_TARGET,
- move_eos_to_beginning=True,
- )
- prev_output_tokens = prev_output_tokens.index_select(0, sort_order)
- target = target.index_select(0, sort_order)
- ntokens = sum(len(s['target']) for s in samples)
- return {
- 'id': id,
- 'ntokens': ntokens,
- 'net_input': {
- 'src_tokens': src_tokens,
- 'src_lengths': src_lengths,
- 'prev_output_tokens': prev_output_tokens,
- },
- 'target': target,
- }
- @staticmethod
- def collate_tokens(values, pad_idx, eos_idx, left_pad, move_eos_to_beginning=False):
- size = max(v.size(0) for v in values)
- res = values[0].new(len(values), size).fill_(pad_idx)
- def copy_tensor(src, dst):
- assert dst.numel() == src.numel()
- if move_eos_to_beginning:
- assert src[-1] == eos_idx
- dst[0] = eos_idx
- dst[1:] = src[:-1]
- else:
- dst.copy_(src)
- for i, v in enumerate(values):
- if left_pad:
- copy_tensor(v, res[i][size-len(v):])
- else:
- copy_tensor(v, res[i][:len(v)])
- return res
- def _valid_size(src_size, dst_size, max_positions):
- if isinstance(max_positions, numbers.Number):
- max_src_positions, max_dst_positions = max_positions, max_positions
- else:
- max_src_positions, max_dst_positions = max_positions
- if src_size < 1 or src_size > max_src_positions:
- return False
- if dst_size is not None and (dst_size < 1 or dst_size > max_dst_positions):
- return False
- return True
- def _make_batches(src, dst, indices, max_tokens, max_sentences, max_positions,
- ignore_invalid_inputs=False, allow_different_src_lens=False,
- required_batch_size_multiple=1):
- batch = []
- mult = required_batch_size_multiple
- def yield_batch(next_idx, num_tokens):
- if len(batch) == 0:
- return False
- if len(batch) == max_sentences:
- return True
- if num_tokens > max_tokens:
- return True
- if not allow_different_src_lens and \
- (src.sizes[batch[0]] != src.sizes[next_idx]):
- return True
- return False
- sample_len = 0
- sample_lens = []
- ignored = []
- for idx in map(int, indices):
- src_size = src.sizes[idx]
- dst_size = dst.sizes[idx] if dst else src_size
- if not _valid_size(src_size, dst_size, max_positions):
- if ignore_invalid_inputs:
- ignored.append(idx)
- continue
- raise Exception((
- "Sample #{} has size (src={}, dst={}) but max size is {}."
- " Skip this example with --skip-invalid-size-inputs-valid-test"
- ).format(idx, src_size, dst_size, max_positions))
- sample_lens.append(max(src_size, dst_size))
- sample_len = max(sample_len, sample_lens[-1])
- num_tokens = (len(batch) + 1) * sample_len
- if yield_batch(idx, num_tokens):
- mod8_len = max(mult * (len(batch) // mult), len(batch) % mult)
- yield batch[:mod8_len]
- batch = batch[mod8_len:]
- sample_lens = sample_lens[mod8_len:]
- sample_len = max(sample_lens) if len(sample_lens) > 0 else 0
- batch.append(idx)
- if len(batch) > 0:
- yield batch
- if len(ignored) > 0:
- print("Warning! {} samples are either too short or too long "
- "and will be ignored, first few sample ids={}".format(len(ignored), ignored[:10]))
- def batches_by_size(src, dst, max_tokens=None, max_sentences=None,
- max_positions=(1024, 1024), ignore_invalid_inputs=False,
- descending=False, required_batch_size_multiple=1, allow_different_src_lens=False):
- """Returns batches of indices sorted by size. Sequences with different
- source lengths are not allowed in the same batch."""
- assert isinstance(src, IndexedDataset) and (dst is None or isinstance(dst, IndexedDataset))
- if max_tokens is None:
- max_tokens = float('Inf')
- if max_sentences is None:
- max_sentences = float('Inf')
- indices = np.argsort(src.sizes, kind='mergesort')
- if descending:
- indices = np.flip(indices, 0)
- return list(_make_batches(
- src, dst, indices, max_tokens, max_sentences, max_positions,
- ignore_invalid_inputs, allow_different_src_lens=allow_different_src_lens,
- required_batch_size_multiple=required_batch_size_multiple,
- ))
- def uneven_batches_by_size(src, dst, max_tokens=None, max_sentences=None,
- max_positions=(1024, 1024),
- required_batch_size_multiple=1):
- """Returns batches of indices bucketed by size. Batches may contain
- sequences of different lengths."""
- assert isinstance(src, IndexedDataset) and isinstance(dst, IndexedDataset)
- if max_tokens is None:
- max_tokens = float('Inf')
- if max_sentences is None:
- max_sentences = float('Inf')
- indices = np.random.permutation(len(src))
- # sort by sizes
- indices = indices[np.argsort(dst.sizes[indices], kind='mergesort')]
- indices = indices[np.argsort(src.sizes[indices], kind='mergesort')]
- batches = list(_make_batches(
- src, dst, indices, max_tokens, max_sentences, max_positions,
- ignore_invalid_inputs=True, allow_different_src_lens=True,
- required_batch_size_multiple=required_batch_size_multiple,
- ))
- return batches
- def mask_batches(batch_sampler, shard_id, num_shards):
- if num_shards == 1:
- return batch_sampler
- res = [
- batch
- for i, batch in enumerate(batch_sampler)
- if i % num_shards == shard_id
- ]
- expected_length = int(math.ceil(len(batch_sampler) / num_shards))
- return res + [[]] * (expected_length - len(res))
- @contextlib.contextmanager
- def numpy_seed(seed):
- """Context manager which seeds the NumPy PRNG with the specified seed and
- restores the state afterward"""
- if seed is None:
- yield
- return
- state = np.random.get_state()
- np.random.seed(seed)
- try:
- yield
- finally:
- np.random.set_state(state)
- def get_dummy_batch(ntokens, src_dict, dst_dict, src_len=128, tgt_len=128):
- bsz = int(ntokens / max(src_len, tgt_len))
- bsz = math.ceil(bsz / 8) * 8
- assert src_dict.pad() == dst_dict.pad()
- pad_idx = src_dict.pad()
- src_vocab, dst_vocab = len(src_dict), len(dst_dict)
- dummy_batch = {}
- dummy_batch['id'] = Variable(torch.arange(bsz).long().cuda())
- dummy_batch['ntokens'] = tgt_len * bsz
- dummy_batch['target'] = Variable(torch.Tensor(bsz, tgt_len).uniform_(pad_idx + 1, dst_vocab - 1).long().cuda())
- input = {}
- input['prev_output_tokens'] = Variable(dummy_batch['target'].data.clone())
- input['src_lengths'] = Variable(torch.LongTensor(bsz).fill_(src_len).cuda())
- input['src_tokens'] = Variable(torch.Tensor(bsz, src_len).uniform_(pad_idx + 1, src_vocab - 1).long().cuda())
- dummy_batch['net_input'] = input
- return dummy_batch
|