File size: 7,480 Bytes
18d81cd
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
c870645
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
from typing import Unpack
import torch
from transformers import (
    Cache,
    EncoderDecoderCache,
    DynamicCache,
    DataCollatorWithFlattening,
    XLMRobertaModel,
    XLMRobertaForSequenceClassification,
    XLMRobertaForMaskedLM,
    XLMRobertaForCausalLM,
    XLMRobertaForTokenClassification,
    XLMRobertaForMultipleChoice,
    XLMRobertaForQuestionAnswering
)
from transformers.modeling_outputs import BaseModelOutputWithPoolingAndCrossAttentions
from transformers.utils import TransformersKwargs


def _unpad_input(input_ids: torch.Tensor, attention_mask: torch.Tensor):
    collator = DataCollatorWithFlattening(return_flash_attn_kwargs=True)
    features = collator([{"input_ids": i[a.bool()].tolist()} for i, a in zip(input_ids, attention_mask)])
    return features


def _pad_output(inputs: torch.Tensor, indices: torch.Tensor, batch: int, seqlen: int,) -> torch.Tensor:
    if inputs.dim() == 3:
        inputs = inputs.squeeze()
    if inputs.dim() == 1:
        output = torch.zeros(batch * seqlen, dtype=inputs.dtype, device=inputs.device)
        output[indices] = inputs
        padded_inputs = output.view(batch, seqlen)
    else:
        _, *rest = inputs.shape
        output = torch.zeros(batch * seqlen, *rest, dtype=inputs.dtype, device=inputs.device)
        output[indices] = inputs
        padded_inputs = output.view(batch, seqlen, *rest)
    return padded_inputs


class UnpadXLMRobertaModel(XLMRobertaModel):
    _no_split_modules = ["XLMRobertaEmbeddings", "XLMRobertaLayer"]

    def __init__(self, config, add_pooling_layer=True):
        super().__init__(config, add_pooling_layer=add_pooling_layer)

    def forward(
        self,
        input_ids: torch.Tensor | None = None,
        attention_mask: torch.Tensor | None = None,
        token_type_ids: torch.Tensor | None = None,
        position_ids: torch.Tensor | None = None,
        inputs_embeds: torch.Tensor | None = None,
        encoder_hidden_states: torch.Tensor | None = None,
        encoder_attention_mask: torch.Tensor | None = None,
        past_key_values: Cache | None = None,
        use_cache: bool | None = None,
        cache_position: torch.Tensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple[torch.Tensor] | BaseModelOutputWithPoolingAndCrossAttentions:

        if (input_ids is None) ^ (inputs_embeds is not None):
            raise ValueError("You must specify exactly one of input_ids or inputs_embeds")

        if self.config.is_decoder:
            use_cache = use_cache if use_cache is not None else self.config.use_cache
        else:
            use_cache = False

        if use_cache and past_key_values is None:
            past_key_values = (
                EncoderDecoderCache(DynamicCache(config=self.config), DynamicCache(config=self.config))
                if encoder_hidden_states is not None or self.config.is_encoder_decoder
                else DynamicCache(config=self.config)
            )

        past_key_values_length = past_key_values.get_seq_length() if past_key_values is not None else 0

        if input_ids is not None:
            device = input_ids.device
            seq_length = input_ids.shape[1]
            batch_size = input_ids.shape[0]
        else:
            device = inputs_embeds.device
            seq_length = inputs_embeds.shape[1]
            batch_size = inputs_embeds.shape[0]

        indices = None
        if self.config._attn_implementation.startswith("flash_attention"):
            if input_ids is None or attention_mask is None:
                raise ValueError("Unpadding requires both input_ids and attention_mask")
            with torch.no_grad():
                indices = torch.nonzero(attention_mask.flatten(), as_tuple=False).flatten()
                features = _unpad_input(input_ids, attention_mask)
                input_ids = features["input_ids"].to(device=device)
                # roberta requires shifting position_ids by 2
                position_ids = (features["position_ids"] + 2).to(device=device)
                attention_mask = None
                kwargs["cu_seq_lens_k"] = features["cu_seq_lens_k"].to(device=device)
                kwargs["cu_seq_lens_q"] = features["cu_seq_lens_q"].to(device=device)
                kwargs["max_length_k"] = features["max_length_k"]
                kwargs["max_length_q"] = features["max_length_q"]

        embedding_output = self.embeddings(
            input_ids=input_ids,
            position_ids=position_ids,
            token_type_ids=token_type_ids,
            inputs_embeds=inputs_embeds,
            past_key_values_length=past_key_values_length,
        )

        attention_mask, encoder_attention_mask = self._create_attention_masks(
            attention_mask=attention_mask,
            encoder_attention_mask=encoder_attention_mask,
            embedding_output=embedding_output,
            encoder_hidden_states=encoder_hidden_states,
            past_key_values=past_key_values,
        )

        encoder_outputs = self.encoder(
            embedding_output,
            attention_mask=attention_mask,
            encoder_hidden_states=encoder_hidden_states,
            encoder_attention_mask=encoder_attention_mask,
            past_key_values=past_key_values,
            use_cache=use_cache,
            position_ids=position_ids,
            **kwargs,
        )

        sequence_output = encoder_outputs.last_hidden_state
        if self.config._attn_implementation.startswith("flash_attention"):
            sequence_output = _pad_output(
                inputs=sequence_output, indices=indices, batch=batch_size, seqlen=seq_length
            )

        pooled_output = self.pooler(sequence_output) if self.pooler is not None else None
        return BaseModelOutputWithPoolingAndCrossAttentions(
            last_hidden_state=sequence_output,
            pooler_output=pooled_output,
            past_key_values=encoder_outputs.past_key_values,
        )


class UnpadXLMRobertaForCausalLM(XLMRobertaForCausalLM):

    def __init__(self, config):
        super().__init__(config)
        self.roberta = UnpadXLMRobertaModel(config, add_pooling_layer=False)
        self.post_init()


class UnpadXLMRobertaForMaskedLM(XLMRobertaForMaskedLM):

    def __init__(self, config):
        super().__init__(config)
        self.roberta = UnpadXLMRobertaModel(config, add_pooling_layer=False)
        self.post_init()


class UnpadXLMRobertaForSequenceClassification(XLMRobertaForSequenceClassification):

    def __init__(self, config):
        super().__init__(config)
        self.roberta = UnpadXLMRobertaModel(config, add_pooling_layer=False)
        self.post_init()


class UnpadXLMRobertaForTokenClassification(XLMRobertaForTokenClassification):

    def __init__(self, config):
        super().__init__(config)
        self.roberta = UnpadXLMRobertaModel(config, add_pooling_layer=False)
        self.post_init()


class UnpadXLMRobertaForMultipleChoice(XLMRobertaForMultipleChoice):

    def __init__(self, config):
        super().__init__(config)
        self.roberta = UnpadXLMRobertaModel(config)
        self.post_init()


class UnpadXLMRobertaForQuestionAnswering(XLMRobertaForQuestionAnswering):

    def __init__(self, config):
        super().__init__(config)
        self.roberta = UnpadXLMRobertaModel(config, add_pooling_layer=False)
        self.post_init()


def enable_xlm_roberta_unpadding():
    XLMRobertaModel.forward = UnpadXLMRobertaModel.forward