File size: 6,474 Bytes
6dc7c27
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
from abc import ABC, abstractmethod
from typing import Callable, Iterable, List, Any, Tuple, Dict, Union, Optional

import numpy as np
import torch

from torch.nn.utils.rnn import pad_sequence
from torch.utils.data import IterableDataset

from src.utils.collections import chunks, flatten

import logging


logger = logging.getLogger(__name__)


def batchify(tensors: List[torch.Tensor], padding_value: int) -> torch.Tensor:
    return pad_sequence(tensors, batch_first=True, padding_value=padding_value)


def batchify_matrices(tensors: List[torch.Tensor], padding_value: int) -> torch.Tensor:
    x = max([t.shape[0] for t in tensors])
    y = max([t.shape[1] for t in tensors])
    out_matrix = torch.zeros((len(tensors), x, y))
    out_matrix += padding_value
    for i, tensor in enumerate(tensors):
        out_matrix[i][0 : tensor.shape[0], 0 : tensor.shape[1]] = tensor
    return out_matrix


def batchify_matrices(tensors: List[torch.Tensor], padding_value: int) -> torch.Tensor:
    x = max([t.shape[0] for t in tensors])
    y = max([t.shape[1] for t in tensors])
    out_matrix = torch.zeros((len(tensors), x, y))
    out_matrix += padding_value
    for i, tensor in enumerate(tensors):
        out_matrix[i][0 : tensor.shape[0], 0 : tensor.shape[1]] = tensor
    return out_matrix


class BaseDataset(IterableDataset):
    def __init__(

        self,

        dataset_iterator_func: Optional[Callable[[], Iterable[Dict[str, Any]]]],

        tokens_per_batch: int,

        max_batch_size: Optional[int],

        main_field: str,

        fields_batchers: Optional[Dict[str, Union[None, Callable[[list], Any]]]],

        section_size: int,

        prebatch: bool,

        shuffle: bool,

        max_length: int,

    ):
        super().__init__()

        # you can subclass TokenBasedDataset in this way
        if dataset_iterator_func is not None:
            self.dataset_iterator_func = dataset_iterator_func

        self.tokens_per_batch = tokens_per_batch
        self.max_batch_size = max_batch_size
        self.main_field = main_field
        self.fields_batcher = fields_batchers
        self.section_size = section_size
        self.prebatch = prebatch
        self.shuffle = shuffle
        self.max_length = max_length

        if self.shuffle and not self.prebatch:
            logger.warning("If you set prebatch to False the shuffle parameters has no effect")

    def prebatch_elements(self, dataset_elements: list) -> list:
        if self.shuffle:
            dataset_elements = sorted(
                dataset_elements,
                key=lambda de: len(de[self.main_field]) + torch.randint(0, 10, (1,)),
            )
            dataset_elements = list(chunks(dataset_elements, 2048))
            np.random.shuffle(dataset_elements)
            dataset_elements = flatten(dataset_elements)
        else:
            dataset_elements = sorted(dataset_elements, key=lambda de: len(de[self.main_field]))

        return dataset_elements

    def materialize_batches(self, dataset_elements: List[Dict[str, Any]]) -> List[Dict[str, Any]]:

        if self.prebatch:
            dataset_elements = self.prebatch_elements(dataset_elements)

        batches = []
        current_batch = []

        # function that creates a batch from the 'current_batch' list
        def output_batch() -> Dict[str, Any]:

            batch_dict = dict()

            de_values_by_field = {fn: [de[fn] for de in current_batch if fn in de] for fn in self.fields_batcher}

            # in case you provide fields batchers but in the batch there are no elements for that field
            de_values_by_field = {fn: fvs for fn, fvs in de_values_by_field.items() if len(fvs) > 0}

            assert len(set([len(v) for v in de_values_by_field.values()]))

            de_values_by_field = {
                fn: fvs for fn, fvs in de_values_by_field.items() if all([fv is not None for fv in fvs])
            }

            for field_name, field_values in de_values_by_field.items():
                field_batch = (
                    self.fields_batcher[field_name](field_values)
                    if self.fields_batcher[field_name] is not None
                    else field_values
                )

                batch_dict[field_name] = field_batch

            return batch_dict

        for de in dataset_elements:

            if self.max_batch_size is not None and len(current_batch) == self.max_batch_size:
                batches.append(output_batch())
                current_batch = []

            de_main_len = len(de[self.main_field])

            # some callback to filter out samples for example

            if de_main_len > self.max_length:
                logger.warning(f"Discarding element: max length exceeded ({de_main_len} > {self.max_length})")
                continue

            if de_main_len > self.tokens_per_batch:
                logger.warning(
                    f'Discarding element: length greater than "tokens per batch"'
                    f" ({de_main_len} > {self.tokens_per_batch})"
                )
                continue

            future_max_len = max(
                de_main_len,
                max([len(bde[self.main_field]) for bde in current_batch], default=0),
            )

            future_tokens_per_batch = future_max_len * (len(current_batch) + 1)

            if future_tokens_per_batch >= self.tokens_per_batch:
                batches.append(output_batch())
                current_batch = []

            current_batch.append(de)

        if len(current_batch) != 0:
            batches.append(output_batch())

        return batches

    def __iter__(self):

        current_dataset_elements = []

        for i, dataset_elem in enumerate(self.dataset_iterator_func()):

            if len(current_dataset_elements) == self.section_size:
                for batch in self.materialize_batches(current_dataset_elements):
                    yield batch
                current_dataset_elements = []

            current_dataset_elements.append(dataset_elem)

            if i % 10_000 == 0:
                logger.info(f"Processed: {i} number of elements")

        if len(current_dataset_elements) != 0:
            for batch in self.materialize_batches(current_dataset_elements):
                yield batch