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1
+ # coding=utf-8
2
+ # Copyright 2022 EleutherAI and the HuggingFace Inc. team. All rights reserved.
3
+ #
4
+ # This code is based on EleutherAI's GPT-NeoX library and the GPT-NeoX
5
+ # and OPT implementations in this library. It has been modified from its
6
+ # original forms to accommodate minor architectural differences compared
7
+ # to GPT-NeoX and OPT used by the Meta AI team that trained the model.
8
+ #
9
+ # Licensed under the Apache License, Version 2.0 (the "License");
10
+ # you may not use this file except in compliance with the License.
11
+ # You may obtain a copy of the License at
12
+ #
13
+ # http://www.apache.org/licenses/LICENSE-2.0
14
+ #
15
+ # Unless required by applicable law or agreed to in writing, software
16
+ # distributed under the License is distributed on an "AS IS" BASIS,
17
+ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18
+ # See the License for the specific language governing permissions and
19
+ # limitations under the License.
20
+ """PyTorch LLaMA model."""
21
+
22
+ import math
23
+ import warnings
24
+ from typing import List, Optional, Tuple, Union
25
+
26
+ import torch
27
+ import torch.nn.functional as F
28
+ import torch.utils.checkpoint
29
+ from torch import nn
30
+ from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss
31
+
32
+ from ...activations import ACT2FN
33
+ from ...cache_utils import Cache, DynamicCache, StaticCache
34
+ from ...modeling_attn_mask_utils import AttentionMaskConverter
35
+ from ...modeling_outputs import (
36
+ BaseModelOutputWithPast,
37
+ CausalLMOutputWithPast,
38
+ QuestionAnsweringModelOutput,
39
+ SequenceClassifierOutputWithPast,
40
+ )
41
+ from ...modeling_utils import PreTrainedModel
42
+ from ...pytorch_utils import ALL_LAYERNORM_LAYERS
43
+ from ...utils import (
44
+ add_start_docstrings,
45
+ add_start_docstrings_to_model_forward,
46
+ is_flash_attn_2_available,
47
+ is_flash_attn_greater_or_equal_2_10,
48
+ logging,
49
+ replace_return_docstrings,
50
+ )
51
+ from .configuration_llama import LlamaConfig
52
+
53
+
54
+ if is_flash_attn_2_available():
55
+ from flash_attn import flash_attn_func, flash_attn_varlen_func
56
+ from flash_attn.bert_padding import index_first_axis, pad_input, unpad_input # noqa
57
+
58
+
59
+ logger = logging.get_logger(__name__)
60
+
61
+ _CONFIG_FOR_DOC = "LlamaConfig"
62
+
63
+
64
+ def _get_unpad_data(attention_mask):
65
+ seqlens_in_batch = attention_mask.sum(dim=-1, dtype=torch.int32)
66
+ indices = torch.nonzero(attention_mask.flatten(), as_tuple=False).flatten()
67
+ max_seqlen_in_batch = seqlens_in_batch.max().item()
68
+ cu_seqlens = F.pad(torch.cumsum(seqlens_in_batch, dim=0, dtype=torch.int32), (1, 0))
69
+ return (
70
+ indices,
71
+ cu_seqlens,
72
+ max_seqlen_in_batch,
73
+ )
74
+
75
+
76
+ class LlamaRMSNorm(nn.Module):
77
+ def __init__(self, hidden_size, eps=1e-6):
78
+ """
79
+ LlamaRMSNorm is equivalent to T5LayerNorm
80
+ """
81
+ super().__init__()
82
+ self.weight = nn.Parameter(torch.ones(hidden_size))
83
+ self.variance_epsilon = eps
84
+
85
+ def forward(self, hidden_states):
86
+ input_dtype = hidden_states.dtype
87
+ hidden_states = hidden_states.to(torch.float32)
88
+ variance = hidden_states.pow(2).mean(-1, keepdim=True)
89
+ hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
90
+ return self.weight * hidden_states.to(input_dtype)
91
+
92
+
93
+ ALL_LAYERNORM_LAYERS.append(LlamaRMSNorm)
94
+
95
+
96
+ class LlamaRotaryEmbedding(nn.Module):
97
+ def __init__(self, dim, max_position_embeddings=2048, base=10000, device=None, scaling_factor=1.0):
98
+ super().__init__()
99
+ self.scaling_factor = scaling_factor
100
+ self.dim = dim
101
+ self.max_position_embeddings = max_position_embeddings
102
+ self.base = base
103
+ inv_freq = 1.0 / (self.base ** (torch.arange(0, self.dim, 2, dtype=torch.int64).float().to(device) / self.dim))
104
+ self.register_buffer("inv_freq", inv_freq, persistent=False)
105
+ # For BC we register cos and sin cached
106
+ self.max_seq_len_cached = max_position_embeddings
107
+ t = torch.arange(self.max_seq_len_cached, device=device, dtype=torch.int64).type_as(self.inv_freq)
108
+ t = t / self.scaling_factor
109
+ freqs = torch.outer(t, self.inv_freq)
110
+ # Different from paper, but it uses a different permutation in order to obtain the same calculation
111
+ emb = torch.cat((freqs, freqs), dim=-1)
112
+ self.register_buffer("_cos_cached", emb.cos().to(torch.get_default_dtype()), persistent=False)
113
+ self.register_buffer("_sin_cached", emb.sin().to(torch.get_default_dtype()), persistent=False)
114
+
115
+ @property
116
+ def sin_cached(self):
117
+ logger.warning_once(
118
+ "The sin_cached attribute will be removed in 4.39. Bear in mind that its contents changed in v4.38. Use "
119
+ "the forward method of RoPE from now on instead. It is not used in the `LlamaAttention` class"
120
+ )
121
+ return self._sin_cached
122
+
123
+ @property
124
+ def cos_cached(self):
125
+ logger.warning_once(
126
+ "The cos_cached attribute will be removed in 4.39. Bear in mind that its contents changed in v4.38. Use "
127
+ "the forward method of RoPE from now on instead. It is not used in the `LlamaAttention` class"
128
+ )
129
+ return self._cos_cached
130
+
131
+ @torch.no_grad()
132
+ def forward(self, x, position_ids):
133
+ # x: [bs, num_attention_heads, seq_len, head_size]
134
+ inv_freq_expanded = self.inv_freq[None, :, None].float().expand(position_ids.shape[0], -1, 1)
135
+ position_ids_expanded = position_ids[:, None, :].float()
136
+ # Force float32 since bfloat16 loses precision on long contexts
137
+ # See https://github.com/huggingface/transformers/pull/29285
138
+ device_type = x.device.type
139
+ device_type = device_type if isinstance(device_type, str) and device_type != "mps" else "cpu"
140
+ with torch.autocast(device_type=device_type, enabled=False):
141
+ freqs = (inv_freq_expanded.float() @ position_ids_expanded.float()).transpose(1, 2)
142
+ emb = torch.cat((freqs, freqs), dim=-1)
143
+ cos = emb.cos()
144
+ sin = emb.sin()
145
+ return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype)
146
+
147
+
148
+ class LlamaLinearScalingRotaryEmbedding(LlamaRotaryEmbedding):
149
+ """LlamaRotaryEmbedding extended with linear scaling. Credits to the Reddit user /u/kaiokendev"""
150
+
151
+ def forward(self, x, position_ids):
152
+ # difference to the original RoPE: a scaling factor is aplied to the position ids
153
+ position_ids = position_ids.float() / self.scaling_factor
154
+ cos, sin = super().forward(x, position_ids)
155
+ return cos, sin
156
+
157
+
158
+ class LlamaDynamicNTKScalingRotaryEmbedding(LlamaRotaryEmbedding):
159
+ """LlamaRotaryEmbedding extended with Dynamic NTK scaling. Credits to the Reddit users /u/bloc97 and /u/emozilla"""
160
+
161
+ def forward(self, x, position_ids):
162
+ # difference to the original RoPE: inv_freq is recomputed when the sequence length > original length
163
+ seq_len = torch.max(position_ids) + 1
164
+ if seq_len > self.max_position_embeddings:
165
+ base = self.base * (
166
+ (self.scaling_factor * seq_len / self.max_position_embeddings) - (self.scaling_factor - 1)
167
+ ) ** (self.dim / (self.dim - 2))
168
+ inv_freq = 1.0 / (
169
+ base ** (torch.arange(0, self.dim, 2, dtype=torch.int64).float().to(x.device) / self.dim)
170
+ )
171
+ self.register_buffer("inv_freq", inv_freq, persistent=False) # TODO joao: this may break with compilation
172
+
173
+ cos, sin = super().forward(x, position_ids)
174
+ return cos, sin
175
+
176
+
177
+ def rotate_half(x):
178
+ """Rotates half the hidden dims of the input."""
179
+ x1 = x[..., : x.shape[-1] // 2]
180
+ x2 = x[..., x.shape[-1] // 2 :]
181
+ return torch.cat((-x2, x1), dim=-1)
182
+
183
+
184
+ def apply_rotary_pos_emb(q, k, cos, sin, position_ids=None, unsqueeze_dim=1):
185
+ """Applies Rotary Position Embedding to the query and key tensors.
186
+
187
+ Args:
188
+ q (`torch.Tensor`): The query tensor.
189
+ k (`torch.Tensor`): The key tensor.
190
+ cos (`torch.Tensor`): The cosine part of the rotary embedding.
191
+ sin (`torch.Tensor`): The sine part of the rotary embedding.
192
+ position_ids (`torch.Tensor`, *optional*):
193
+ Deprecated and unused.
194
+ unsqueeze_dim (`int`, *optional*, defaults to 1):
195
+ The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
196
+ sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
197
+ that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
198
+ k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
199
+ cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
200
+ the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
201
+ Returns:
202
+ `tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
203
+ """
204
+ cos = cos.unsqueeze(unsqueeze_dim)
205
+ sin = sin.unsqueeze(unsqueeze_dim)
206
+ q_embed = (q * cos) + (rotate_half(q) * sin)
207
+ k_embed = (k * cos) + (rotate_half(k) * sin)
208
+ return q_embed, k_embed
209
+
210
+
211
+ class LlamaMLP(nn.Module):
212
+ def __init__(self, config):
213
+ super().__init__()
214
+ self.config = config
215
+ self.hidden_size = config.hidden_size
216
+ self.intermediate_size = config.intermediate_size
217
+ self.gate_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
218
+ self.up_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
219
+ self.down_proj = nn.Linear(self.intermediate_size, self.hidden_size, bias=False)
220
+ self.act_fn = ACT2FN[config.hidden_act]
221
+
222
+ def forward(self, x):
223
+ if self.config.pretraining_tp > 1:
224
+ slice = self.intermediate_size // self.config.pretraining_tp
225
+ gate_proj_slices = self.gate_proj.weight.split(slice, dim=0)
226
+ up_proj_slices = self.up_proj.weight.split(slice, dim=0)
227
+ down_proj_slices = self.down_proj.weight.split(slice, dim=1)
228
+
229
+ gate_proj = torch.cat(
230
+ [F.linear(x, gate_proj_slices[i]) for i in range(self.config.pretraining_tp)], dim=-1
231
+ )
232
+ up_proj = torch.cat([F.linear(x, up_proj_slices[i]) for i in range(self.config.pretraining_tp)], dim=-1)
233
+
234
+ intermediate_states = (self.act_fn(gate_proj) * up_proj).split(slice, dim=2)
235
+ down_proj = [
236
+ F.linear(intermediate_states[i], down_proj_slices[i]) for i in range(self.config.pretraining_tp)
237
+ ]
238
+ down_proj = sum(down_proj)
239
+ else:
240
+ down_proj = self.down_proj(self.act_fn(self.gate_proj(x)) * self.up_proj(x))
241
+
242
+ return down_proj
243
+
244
+
245
+ def repeat_kv(hidden_states: torch.Tensor, n_rep: int) -> torch.Tensor:
246
+ """
247
+ This is the equivalent of torch.repeat_interleave(x, dim=1, repeats=n_rep). The hidden states go from (batch,
248
+ num_key_value_heads, seqlen, head_dim) to (batch, num_attention_heads, seqlen, head_dim)
249
+ """
250
+ batch, num_key_value_heads, slen, head_dim = hidden_states.shape
251
+ if n_rep == 1:
252
+ return hidden_states
253
+ hidden_states = hidden_states[:, :, None, :, :].expand(batch, num_key_value_heads, n_rep, slen, head_dim)
254
+ return hidden_states.reshape(batch, num_key_value_heads * n_rep, slen, head_dim)
255
+
256
+
257
+ class LlamaAttention(nn.Module):
258
+ """Multi-headed attention from 'Attention Is All You Need' paper"""
259
+
260
+ def __init__(self, config: LlamaConfig, layer_idx: Optional[int] = None):
261
+ super().__init__()
262
+ self.config = config
263
+ self.layer_idx = layer_idx
264
+ if layer_idx is None:
265
+ logger.warning_once(
266
+ f"Instantiating {self.__class__.__name__} without passing a `layer_idx` is not recommended and will "
267
+ "lead to errors during the forward call if caching is used. Please make sure to provide a `layer_idx` "
268
+ "when creating this class."
269
+ )
270
+
271
+ self.attention_dropout = config.attention_dropout
272
+ self.hidden_size = config.hidden_size
273
+ self.num_heads = config.num_attention_heads
274
+ self.head_dim = self.hidden_size // self.num_heads
275
+ self.num_key_value_heads = config.num_key_value_heads
276
+ self.num_key_value_groups = self.num_heads // self.num_key_value_heads
277
+ self.max_position_embeddings = config.max_position_embeddings
278
+ self.rope_theta = config.rope_theta
279
+ self.is_causal = True
280
+
281
+ if (self.head_dim * self.num_heads) != self.hidden_size:
282
+ raise ValueError(
283
+ f"hidden_size must be divisible by num_heads (got `hidden_size`: {self.hidden_size}"
284
+ f" and `num_heads`: {self.num_heads})."
285
+ )
286
+
287
+ self.q_proj = nn.Linear(self.hidden_size, self.num_heads * self.head_dim, bias=config.attention_bias)
288
+ self.k_proj = nn.Linear(self.hidden_size, self.num_key_value_heads * self.head_dim, bias=config.attention_bias)
289
+ self.v_proj = nn.Linear(self.hidden_size, self.num_key_value_heads * self.head_dim, bias=config.attention_bias)
290
+ self.o_proj = nn.Linear(self.hidden_size, self.hidden_size, bias=config.attention_bias)
291
+ self._init_rope()
292
+
293
+ def _init_rope(self):
294
+ if self.config.rope_scaling is None:
295
+ self.rotary_emb = LlamaRotaryEmbedding(
296
+ self.head_dim,
297
+ max_position_embeddings=self.max_position_embeddings,
298
+ base=self.rope_theta,
299
+ )
300
+ else:
301
+ scaling_type = self.config.rope_scaling["type"]
302
+ scaling_factor = self.config.rope_scaling["factor"]
303
+ if scaling_type == "linear":
304
+ self.rotary_emb = LlamaLinearScalingRotaryEmbedding(
305
+ self.head_dim,
306
+ max_position_embeddings=self.max_position_embeddings,
307
+ scaling_factor=scaling_factor,
308
+ base=self.rope_theta,
309
+ )
310
+ elif scaling_type == "dynamic":
311
+ self.rotary_emb = LlamaDynamicNTKScalingRotaryEmbedding(
312
+ self.head_dim,
313
+ max_position_embeddings=self.max_position_embeddings,
314
+ scaling_factor=scaling_factor,
315
+ base=self.rope_theta,
316
+ )
317
+ else:
318
+ raise ValueError(f"Unknown RoPE scaling type {scaling_type}")
319
+
320
+ def forward(
321
+ self,
322
+ hidden_states: torch.Tensor,
323
+ attention_mask: Optional[torch.Tensor] = None,
324
+ position_ids: Optional[torch.LongTensor] = None,
325
+ past_key_value: Optional[Cache] = None,
326
+ output_attentions: bool = False,
327
+ use_cache: bool = False,
328
+ cache_position: Optional[torch.LongTensor] = None,
329
+ **kwargs,
330
+ ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
331
+ bsz, q_len, _ = hidden_states.size()
332
+
333
+ if self.config.pretraining_tp > 1:
334
+ key_value_slicing = (self.num_key_value_heads * self.head_dim) // self.config.pretraining_tp
335
+ query_slices = self.q_proj.weight.split(
336
+ (self.num_heads * self.head_dim) // self.config.pretraining_tp, dim=0
337
+ )
338
+ key_slices = self.k_proj.weight.split(key_value_slicing, dim=0)
339
+ value_slices = self.v_proj.weight.split(key_value_slicing, dim=0)
340
+
341
+ query_states = [F.linear(hidden_states, query_slices[i]) for i in range(self.config.pretraining_tp)]
342
+ query_states = torch.cat(query_states, dim=-1)
343
+
344
+ key_states = [F.linear(hidden_states, key_slices[i]) for i in range(self.config.pretraining_tp)]
345
+ key_states = torch.cat(key_states, dim=-1)
346
+
347
+ value_states = [F.linear(hidden_states, value_slices[i]) for i in range(self.config.pretraining_tp)]
348
+ value_states = torch.cat(value_states, dim=-1)
349
+
350
+ else:
351
+ query_states = self.q_proj(hidden_states)
352
+ key_states = self.k_proj(hidden_states)
353
+ value_states = self.v_proj(hidden_states)
354
+
355
+ query_states = query_states.view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
356
+ key_states = key_states.view(bsz, q_len, self.num_key_value_heads, self.head_dim).transpose(1, 2)
357
+ value_states = value_states.view(bsz, q_len, self.num_key_value_heads, self.head_dim).transpose(1, 2)
358
+
359
+ past_key_value = getattr(self, "past_key_value", past_key_value)
360
+ cos, sin = self.rotary_emb(value_states, position_ids)
361
+ query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin)
362
+
363
+ if past_key_value is not None:
364
+ # sin and cos are specific to RoPE models; cache_position needed for the static cache
365
+ cache_kwargs = {"sin": sin, "cos": cos, "cache_position": cache_position}
366
+ key_states, value_states = past_key_value.update(key_states, value_states, self.layer_idx, cache_kwargs)
367
+
368
+ key_states = repeat_kv(key_states, self.num_key_value_groups)
369
+ value_states = repeat_kv(value_states, self.num_key_value_groups)
370
+
371
+ attn_weights = torch.matmul(query_states, key_states.transpose(2, 3)) / math.sqrt(self.head_dim)
372
+
373
+ if attention_mask is not None: # no matter the length, we just slice it
374
+ causal_mask = attention_mask[:, :, :, : key_states.shape[-2]]
375
+ attn_weights = attn_weights + causal_mask
376
+
377
+ # upcast attention to fp32
378
+ attn_weights = nn.functional.softmax(attn_weights, dim=-1, dtype=torch.float32).to(query_states.dtype)
379
+ attn_weights = nn.functional.dropout(attn_weights, p=self.attention_dropout, training=self.training)
380
+ attn_output = torch.matmul(attn_weights, value_states)
381
+
382
+ if attn_output.size() != (bsz, self.num_heads, q_len, self.head_dim):
383
+ raise ValueError(
384
+ f"`attn_output` should be of size {(bsz, self.num_heads, q_len, self.head_dim)}, but is"
385
+ f" {attn_output.size()}"
386
+ )
387
+
388
+ attn_output = attn_output.transpose(1, 2).contiguous()
389
+
390
+ attn_output = attn_output.reshape(bsz, q_len, self.hidden_size)
391
+
392
+ if self.config.pretraining_tp > 1:
393
+ attn_output = attn_output.split(self.hidden_size // self.config.pretraining_tp, dim=2)
394
+ o_proj_slices = self.o_proj.weight.split(self.hidden_size // self.config.pretraining_tp, dim=1)
395
+ attn_output = sum([F.linear(attn_output[i], o_proj_slices[i]) for i in range(self.config.pretraining_tp)])
396
+ else:
397
+ attn_output = self.o_proj(attn_output)
398
+
399
+ if not output_attentions:
400
+ attn_weights = None
401
+
402
+ return attn_output, attn_weights, past_key_value
403
+
404
+
405
+ class LlamaFlashAttention2(LlamaAttention):
406
+ """
407
+ Llama flash attention module. This module inherits from `LlamaAttention` as the weights of the module stays
408
+ untouched. The only required change would be on the forward pass where it needs to correctly call the public API of
409
+ flash attention and deal with padding tokens in case the input contains any of them.
410
+ """
411
+
412
+ def __init__(self, *args, **kwargs):
413
+ super().__init__(*args, **kwargs)
414
+
415
+ # TODO: Should be removed once Flash Attention for RoCm is bumped to 2.1.
416
+ # flash_attn<2.1 generates top-left aligned causal mask, while what is needed here is bottom-right alignement, that was made default for flash_attn>=2.1. This attribute is used to handle this difference. Reference: https://github.com/Dao-AILab/flash-attention/releases/tag/v2.1.0.
417
+ # Beware that with flash_attn<2.1, using q_seqlen != k_seqlen (except for the case q_seqlen == 1) produces a wrong mask (top-left).
418
+ self._flash_attn_uses_top_left_mask = not is_flash_attn_greater_or_equal_2_10()
419
+
420
+ def forward(
421
+ self,
422
+ hidden_states: torch.Tensor,
423
+ attention_mask: Optional[torch.LongTensor] = None,
424
+ position_ids: Optional[torch.LongTensor] = None,
425
+ past_key_value: Optional[Cache] = None,
426
+ output_attentions: bool = False,
427
+ use_cache: bool = False,
428
+ cache_position: Optional[torch.LongTensor] = None,
429
+ **kwargs,
430
+ ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
431
+ output_attentions = False
432
+
433
+ bsz, q_len, _ = hidden_states.size()
434
+
435
+ query_states = self.q_proj(hidden_states)
436
+ key_states = self.k_proj(hidden_states)
437
+ value_states = self.v_proj(hidden_states)
438
+
439
+ # Flash attention requires the input to have the shape
440
+ # batch_size x seq_length x head_dim x hidden_dim
441
+ # therefore we just need to keep the original shape
442
+ query_states = query_states.view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
443
+ key_states = key_states.view(bsz, q_len, self.num_key_value_heads, self.head_dim).transpose(1, 2)
444
+ value_states = value_states.view(bsz, q_len, self.num_key_value_heads, self.head_dim).transpose(1, 2)
445
+
446
+ cos, sin = self.rotary_emb(value_states, position_ids)
447
+ query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin)
448
+
449
+ past_key_value = getattr(self, "past_key_value", past_key_value)
450
+
451
+ if past_key_value is not None:
452
+ # sin and cos are specific to RoPE models; cache_position needed for the static cache
453
+ cache_kwargs = {"sin": sin, "cos": cos, "cache_position": cache_position}
454
+ key_states, value_states = past_key_value.update(key_states, value_states, self.layer_idx, cache_kwargs)
455
+
456
+ # TODO: These transpose are quite inefficient but Flash Attention requires the layout [batch_size, sequence_length, num_heads, head_dim]. We would need to refactor the KV cache
457
+ # to be able to avoid many of these transpose/reshape/view.
458
+ query_states = query_states.transpose(1, 2)
459
+ key_states = key_states.transpose(1, 2)
460
+ value_states = value_states.transpose(1, 2)
461
+
462
+ dropout_rate = self.attention_dropout if self.training else 0.0
463
+
464
+ # In PEFT, usually we cast the layer norms in float32 for training stability reasons
465
+ # therefore the input hidden states gets silently casted in float32. Hence, we need
466
+ # cast them back in the correct dtype just to be sure everything works as expected.
467
+ # This might slowdown training & inference so it is recommended to not cast the LayerNorms
468
+ # in fp32. (LlamaRMSNorm handles it correctly)
469
+
470
+ input_dtype = query_states.dtype
471
+ if input_dtype == torch.float32:
472
+ if torch.is_autocast_enabled():
473
+ target_dtype = torch.get_autocast_gpu_dtype()
474
+ # Handle the case where the model is quantized
475
+ elif hasattr(self.config, "_pre_quantization_dtype"):
476
+ target_dtype = self.config._pre_quantization_dtype
477
+ else:
478
+ target_dtype = self.q_proj.weight.dtype
479
+
480
+ logger.warning_once(
481
+ f"The input hidden states seems to be silently casted in float32, this might be related to"
482
+ f" the fact you have upcasted embedding or layer norm layers in float32. We will cast back the input in"
483
+ f" {target_dtype}."
484
+ )
485
+
486
+ query_states = query_states.to(target_dtype)
487
+ key_states = key_states.to(target_dtype)
488
+ value_states = value_states.to(target_dtype)
489
+
490
+ attn_output = self._flash_attention_forward(
491
+ query_states, key_states, value_states, attention_mask, q_len, dropout=dropout_rate
492
+ )
493
+
494
+ attn_output = attn_output.reshape(bsz, q_len, self.hidden_size).contiguous()
495
+ attn_output = self.o_proj(attn_output)
496
+
497
+ if not output_attentions:
498
+ attn_weights = None
499
+
500
+ return attn_output, attn_weights, past_key_value
501
+
502
+ def _flash_attention_forward(
503
+ self, query_states, key_states, value_states, attention_mask, query_length, dropout=0.0, softmax_scale=None
504
+ ):
505
+ """
506
+ Calls the forward method of Flash Attention - if the input hidden states contain at least one padding token
507
+ first unpad the input, then computes the attention scores and pad the final attention scores.
508
+
509
+ Args:
510
+ query_states (`torch.Tensor`):
511
+ Input query states to be passed to Flash Attention API
512
+ key_states (`torch.Tensor`):
513
+ Input key states to be passed to Flash Attention API
514
+ value_states (`torch.Tensor`):
515
+ Input value states to be passed to Flash Attention API
516
+ attention_mask (`torch.Tensor`):
517
+ The padding mask - corresponds to a tensor of size `(batch_size, seq_len)` where 0 stands for the
518
+ position of padding tokens and 1 for the position of non-padding tokens.
519
+ dropout (`float`):
520
+ Attention dropout
521
+ softmax_scale (`float`, *optional*):
522
+ The scaling of QK^T before applying softmax. Default to 1 / sqrt(head_dim)
523
+ """
524
+ if not self._flash_attn_uses_top_left_mask:
525
+ causal = self.is_causal
526
+ else:
527
+ # TODO: Remove the `query_length != 1` check once Flash Attention for RoCm is bumped to 2.1. For details, please see the comment in LlamaFlashAttention2 __init__.
528
+ causal = self.is_causal and query_length != 1
529
+
530
+ # Contains at least one padding token in the sequence
531
+ if attention_mask is not None:
532
+ batch_size = query_states.shape[0]
533
+ query_states, key_states, value_states, indices_q, cu_seq_lens, max_seq_lens = self._upad_input(
534
+ query_states, key_states, value_states, attention_mask, query_length
535
+ )
536
+
537
+ cu_seqlens_q, cu_seqlens_k = cu_seq_lens
538
+ max_seqlen_in_batch_q, max_seqlen_in_batch_k = max_seq_lens
539
+
540
+ attn_output_unpad = flash_attn_varlen_func(
541
+ query_states,
542
+ key_states,
543
+ value_states,
544
+ cu_seqlens_q=cu_seqlens_q,
545
+ cu_seqlens_k=cu_seqlens_k,
546
+ max_seqlen_q=max_seqlen_in_batch_q,
547
+ max_seqlen_k=max_seqlen_in_batch_k,
548
+ dropout_p=dropout,
549
+ softmax_scale=softmax_scale,
550
+ causal=causal,
551
+ )
552
+
553
+ attn_output = pad_input(attn_output_unpad, indices_q, batch_size, query_length)
554
+ else:
555
+ attn_output = flash_attn_func(
556
+ query_states, key_states, value_states, dropout, softmax_scale=softmax_scale, causal=causal
557
+ )
558
+
559
+ return attn_output
560
+
561
+ def _upad_input(self, query_layer, key_layer, value_layer, attention_mask, query_length):
562
+ indices_k, cu_seqlens_k, max_seqlen_in_batch_k = _get_unpad_data(attention_mask)
563
+ batch_size, kv_seq_len, num_key_value_heads, head_dim = key_layer.shape
564
+
565
+ key_layer = index_first_axis(
566
+ key_layer.reshape(batch_size * kv_seq_len, num_key_value_heads, head_dim), indices_k
567
+ )
568
+ value_layer = index_first_axis(
569
+ value_layer.reshape(batch_size * kv_seq_len, num_key_value_heads, head_dim), indices_k
570
+ )
571
+ if query_length == kv_seq_len:
572
+ query_layer = index_first_axis(
573
+ query_layer.reshape(batch_size * kv_seq_len, self.num_heads, head_dim), indices_k
574
+ )
575
+ cu_seqlens_q = cu_seqlens_k
576
+ max_seqlen_in_batch_q = max_seqlen_in_batch_k
577
+ indices_q = indices_k
578
+ elif query_length == 1:
579
+ max_seqlen_in_batch_q = 1
580
+ cu_seqlens_q = torch.arange(
581
+ batch_size + 1, dtype=torch.int32, device=query_layer.device
582
+ ) # There is a memcpy here, that is very bad.
583
+ indices_q = cu_seqlens_q[:-1]
584
+ query_layer = query_layer.squeeze(1)
585
+ else:
586
+ # The -q_len: slice assumes left padding.
587
+ attention_mask = attention_mask[:, -query_length:]
588
+ query_layer, indices_q, cu_seqlens_q, max_seqlen_in_batch_q = unpad_input(query_layer, attention_mask)
589
+
590
+ return (
591
+ query_layer,
592
+ key_layer,
593
+ value_layer,
594
+ indices_q,
595
+ (cu_seqlens_q, cu_seqlens_k),
596
+ (max_seqlen_in_batch_q, max_seqlen_in_batch_k),
597
+ )
598
+
599
+
600
+ class LlamaSdpaAttention(LlamaAttention):
601
+ """
602
+ Llama attention module using torch.nn.functional.scaled_dot_product_attention. This module inherits from
603
+ `LlamaAttention` as the weights of the module stays untouched. The only changes are on the forward pass to adapt to
604
+ SDPA API.
605
+ """
606
+
607
+ # Adapted from LlamaAttention.forward
608
+ def forward(
609
+ self,
610
+ hidden_states: torch.Tensor,
611
+ attention_mask: Optional[torch.Tensor] = None,
612
+ position_ids: Optional[torch.LongTensor] = None,
613
+ past_key_value: Optional[Cache] = None,
614
+ output_attentions: bool = False,
615
+ use_cache: bool = False,
616
+ cache_position: Optional[torch.LongTensor] = None,
617
+ ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
618
+ if output_attentions:
619
+ # TODO: Improve this warning with e.g. `model.config.attn_implementation = "manual"` once this is implemented.
620
+ logger.warning_once(
621
+ "LlamaModel is using LlamaSdpaAttention, but `torch.nn.functional.scaled_dot_product_attention` does not support `output_attentions=True`. Falling back to the manual attention implementation, "
622
+ 'but specifying the manual implementation will be required from Transformers version v5.0.0 onwards. This warning can be removed using the argument `attn_implementation="eager"` when loading the model.'
623
+ )
624
+ return super().forward(
625
+ hidden_states=hidden_states,
626
+ attention_mask=attention_mask,
627
+ position_ids=position_ids,
628
+ past_key_value=past_key_value,
629
+ output_attentions=output_attentions,
630
+ use_cache=use_cache,
631
+ cache_position=cache_position,
632
+ )
633
+
634
+ bsz, q_len, _ = hidden_states.size()
635
+
636
+ query_states = self.q_proj(hidden_states)
637
+ key_states = self.k_proj(hidden_states)
638
+ value_states = self.v_proj(hidden_states)
639
+
640
+ query_states = query_states.view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
641
+ key_states = key_states.view(bsz, q_len, self.num_key_value_heads, self.head_dim).transpose(1, 2)
642
+ value_states = value_states.view(bsz, q_len, self.num_key_value_heads, self.head_dim).transpose(1, 2)
643
+
644
+ cos, sin = self.rotary_emb(value_states, position_ids)
645
+ query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin)
646
+
647
+ # In case static cache is used, it is an instance attribute.
648
+ past_key_value = getattr(self, "past_key_value", past_key_value)
649
+
650
+ if past_key_value is not None:
651
+ # sin and cos are specific to RoPE models; cache_position needed for the static cache
652
+ cache_kwargs = {"sin": sin, "cos": cos, "cache_position": cache_position}
653
+ key_states, value_states = past_key_value.update(key_states, value_states, self.layer_idx, cache_kwargs)
654
+
655
+ key_states = repeat_kv(key_states, self.num_key_value_groups)
656
+ value_states = repeat_kv(value_states, self.num_key_value_groups)
657
+
658
+ causal_mask = attention_mask
659
+ if attention_mask is not None:
660
+ causal_mask = causal_mask[:, :, :, : key_states.shape[-2]]
661
+
662
+ # SDPA with memory-efficient backend is currently (torch==2.1.2) bugged with non-contiguous inputs with custom attn_mask,
663
+ # Reference: https://github.com/pytorch/pytorch/issues/112577.
664
+ if query_states.device.type == "cuda" and causal_mask is not None:
665
+ query_states = query_states.contiguous()
666
+ key_states = key_states.contiguous()
667
+ value_states = value_states.contiguous()
668
+
669
+ # In case we are not compiling, we may set `causal_mask` to None, which is required to dispatch to SDPA's Flash Attention 2 backend, rather
670
+ # relying on the `is_causal` argument.
671
+ attn_output = torch.nn.functional.scaled_dot_product_attention(
672
+ query_states,
673
+ key_states,
674
+ value_states,
675
+ attn_mask=causal_mask,
676
+ dropout_p=self.attention_dropout if self.training else 0.0,
677
+ is_causal=causal_mask is None and q_len > 1,
678
+ )
679
+
680
+ attn_output = attn_output.transpose(1, 2).contiguous()
681
+ attn_output = attn_output.view(bsz, q_len, self.hidden_size)
682
+
683
+ attn_output = self.o_proj(attn_output)
684
+
685
+ return attn_output, None, past_key_value
686
+
687
+
688
+ LLAMA_ATTENTION_CLASSES = {
689
+ "eager": LlamaAttention,
690
+ "flash_attention_2": LlamaFlashAttention2,
691
+ "sdpa": LlamaSdpaAttention,
692
+ }
693
+
694
+
695
+ class LlamaDecoderLayer(nn.Module):
696
+ def __init__(self, config: LlamaConfig, layer_idx: int):
697
+ super().__init__()
698
+ self.hidden_size = config.hidden_size
699
+
700
+ self.self_attn = LLAMA_ATTENTION_CLASSES[config._attn_implementation](config=config, layer_idx=layer_idx)
701
+
702
+ self.mlp = LlamaMLP(config)
703
+ self.input_layernorm = LlamaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
704
+ self.post_attention_layernorm = LlamaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
705
+
706
+ def forward(
707
+ self,
708
+ hidden_states: torch.Tensor,
709
+ attention_mask: Optional[torch.Tensor] = None,
710
+ position_ids: Optional[torch.LongTensor] = None,
711
+ past_key_value: Optional[Tuple[torch.Tensor]] = None,
712
+ output_attentions: Optional[bool] = False,
713
+ use_cache: Optional[bool] = False,
714
+ cache_position: Optional[torch.LongTensor] = None,
715
+ **kwargs,
716
+ ) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]:
717
+ """
718
+ Args:
719
+ hidden_states (`torch.FloatTensor`): input to the layer of shape `(batch, seq_len, embed_dim)`
720
+ attention_mask (`torch.FloatTensor`, *optional*):
721
+ attention mask of size `(batch_size, sequence_length)` if flash attention is used or `(batch_size, 1,
722
+ query_sequence_length, key_sequence_length)` if default attention is used.
723
+ output_attentions (`bool`, *optional*):
724
+ Whether or not to return the attentions tensors of all attention layers. See `attentions` under
725
+ returned tensors for more detail.
726
+ use_cache (`bool`, *optional*):
727
+ If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding
728
+ (see `past_key_values`).
729
+ past_key_value (`Tuple(torch.FloatTensor)`, *optional*): cached past key and value projection states
730
+ """
731
+ if "padding_mask" in kwargs:
732
+ warnings.warn(
733
+ "Passing `padding_mask` is deprecated and will be removed in v4.37. Please make sure use `attention_mask` instead.`"
734
+ )
735
+
736
+ residual = hidden_states
737
+
738
+ hidden_states = self.input_layernorm(hidden_states)
739
+
740
+ # Self Attention
741
+ hidden_states, self_attn_weights, present_key_value = self.self_attn(
742
+ hidden_states=hidden_states,
743
+ attention_mask=attention_mask,
744
+ position_ids=position_ids,
745
+ past_key_value=past_key_value,
746
+ output_attentions=output_attentions,
747
+ use_cache=use_cache,
748
+ cache_position=cache_position,
749
+ **kwargs,
750
+ )
751
+ hidden_states = residual + hidden_states
752
+
753
+ # Fully Connected
754
+ residual = hidden_states
755
+ hidden_states = self.post_attention_layernorm(hidden_states)
756
+ hidden_states = self.mlp(hidden_states)
757
+ hidden_states = residual + hidden_states
758
+
759
+ outputs = (hidden_states,)
760
+
761
+ if output_attentions:
762
+ outputs += (self_attn_weights,)
763
+
764
+ if use_cache:
765
+ outputs += (present_key_value,)
766
+
767
+ return outputs
768
+
769
+
770
+ LLAMA_START_DOCSTRING = r"""
771
+ This model inherits from [`PreTrainedModel`]. Check the superclass documentation for the generic methods the
772
+ library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads
773
+ etc.)
774
+
775
+ This model is also a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) subclass.
776
+ Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage
777
+ and behavior.
778
+
779
+ Parameters:
780
+ config ([`LlamaConfig`]):
781
+ Model configuration class with all the parameters of the model. Initializing with a config file does not
782
+ load the weights associated with the model, only the configuration. Check out the
783
+ [`~PreTrainedModel.from_pretrained`] method to load the model weights.
784
+ """
785
+
786
+
787
+ @add_start_docstrings(
788
+ "The bare LLaMA Model outputting raw hidden-states without any specific head on top.",
789
+ LLAMA_START_DOCSTRING,
790
+ )
791
+ class LlamaPreTrainedModel(PreTrainedModel):
792
+ config_class = LlamaConfig
793
+ base_model_prefix = "model"
794
+ supports_gradient_checkpointing = True
795
+ _no_split_modules = ["LlamaDecoderLayer"]
796
+ _skip_keys_device_placement = ["past_key_values"]
797
+ _supports_flash_attn_2 = True
798
+ _supports_sdpa = True
799
+ _supports_cache_class = True
800
+
801
+ def _init_weights(self, module):
802
+ std = self.config.initializer_range
803
+ if isinstance(module, nn.Linear):
804
+ module.weight.data.normal_(mean=0.0, std=std)
805
+ if module.bias is not None:
806
+ module.bias.data.zero_()
807
+ elif isinstance(module, nn.Embedding):
808
+ module.weight.data.normal_(mean=0.0, std=std)
809
+ if module.padding_idx is not None:
810
+ module.weight.data[module.padding_idx].zero_()
811
+
812
+ def _setup_cache(self, cache_cls, max_batch_size, max_cache_len: Optional[int] = None):
813
+ if self.config._attn_implementation == "flash_attention_2" and cache_cls == StaticCache:
814
+ raise ValueError(
815
+ "`static` cache implementation is not compatible with `attn_implementation==flash_attention_2` "
816
+ "make sure to use `sdpa` in the mean time, and open an issue at https://github.com/huggingface/transformers"
817
+ )
818
+
819
+ for layer in self.model.layers:
820
+ device = layer.input_layernorm.weight.device
821
+ if hasattr(self.config, "_pre_quantization_dtype"):
822
+ dtype = self.config._pre_quantization_dtype
823
+ else:
824
+ dtype = layer.self_attn.o_proj.weight.dtype
825
+ layer.self_attn.past_key_value = cache_cls(
826
+ self.config, max_batch_size, max_cache_len, device=device, dtype=dtype
827
+ )
828
+
829
+ def _reset_cache(self):
830
+ for layer in self.model.layers:
831
+ layer.self_attn.past_key_value = None
832
+
833
+
834
+ LLAMA_INPUTS_DOCSTRING = r"""
835
+ Args:
836
+ input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
837
+ Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you provide
838
+ it.
839
+
840
+ Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
841
+ [`PreTrainedTokenizer.__call__`] for details.
842
+
843
+ [What are input IDs?](../glossary#input-ids)
844
+ attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*):
845
+ Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`:
846
+
847
+ - 1 for tokens that are **not masked**,
848
+ - 0 for tokens that are **masked**.
849
+
850
+ [What are attention masks?](../glossary#attention-mask)
851
+
852
+ Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
853
+ [`PreTrainedTokenizer.__call__`] for details.
854
+
855
+ If `past_key_values` is used, optionally only the last `input_ids` have to be input (see
856
+ `past_key_values`).
857
+
858
+ If you want to change padding behavior, you should read [`modeling_opt._prepare_decoder_attention_mask`]
859
+ and modify to your needs. See diagram 1 in [the paper](https://arxiv.org/abs/1910.13461) for more
860
+ information on the default strategy.
861
+
862
+ - 1 indicates the head is **not masked**,
863
+ - 0 indicates the head is **masked**.
864
+ position_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
865
+ Indices of positions of each input sequence tokens in the position embeddings. Selected in the range `[0,
866
+ config.n_positions - 1]`.
867
+
868
+ [What are position IDs?](../glossary#position-ids)
869
+ past_key_values (`Cache` or `tuple(tuple(torch.FloatTensor))`, *optional*):
870
+ Pre-computed hidden-states (key and values in the self-attention blocks and in the cross-attention
871
+ blocks) that can be used to speed up sequential decoding. This typically consists in the `past_key_values`
872
+ returned by the model at a previous stage of decoding, when `use_cache=True` or `config.use_cache=True`.
873
+
874
+ Two formats are allowed:
875
+ - a [`~cache_utils.Cache`] instance;
876
+ - Tuple of `tuple(torch.FloatTensor)` of length `config.n_layers`, with each tuple having 2 tensors of
877
+ shape `(batch_size, num_heads, sequence_length, embed_size_per_head)`). This is also known as the legacy
878
+ cache format.
879
+
880
+ The model will output the same cache format that is fed as input. If no `past_key_values` are passed, the
881
+ legacy cache format will be returned.
882
+
883
+ If `past_key_values` are used, the user can optionally input only the last `input_ids` (those that don't
884
+ have their past key value states given to this model) of shape `(batch_size, 1)` instead of all `input_ids`
885
+ of shape `(batch_size, sequence_length)`.
886
+ inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*):
887
+ Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. This
888
+ is useful if you want more control over how to convert `input_ids` indices into associated vectors than the
889
+ model's internal embedding lookup matrix.
890
+ use_cache (`bool`, *optional*):
891
+ If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding (see
892
+ `past_key_values`).
893
+ output_attentions (`bool`, *optional*):
894
+ Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned
895
+ tensors for more detail.
896
+ output_hidden_states (`bool`, *optional*):
897
+ Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for
898
+ more detail.
899
+ return_dict (`bool`, *optional*):
900
+ Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
901
+ cache_position (`torch.LongTensor` of shape `(sequence_length)`, *optional*):
902
+ Indices depicting the position of the input sequence tokens in the sequence. Contrarily to `position_ids`,
903
+ this tensor is not affected by padding. It is used to update the cache in the correct position and to infer
904
+ the complete sequence length.
905
+ """
906
+
907
+
908
+ @add_start_docstrings(
909
+ "The bare LLaMA Model outputting raw hidden-states without any specific head on top.",
910
+ LLAMA_START_DOCSTRING,
911
+ )
912
+ class LlamaModel(LlamaPreTrainedModel):
913
+ """
914
+ Transformer decoder consisting of *config.num_hidden_layers* layers. Each layer is a [`LlamaDecoderLayer`]
915
+
916
+ Args:
917
+ config: LlamaConfig
918
+ """
919
+
920
+ def __init__(self, config: LlamaConfig):
921
+ super().__init__(config)
922
+ self.padding_idx = config.pad_token_id
923
+ self.vocab_size = config.vocab_size
924
+
925
+ self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size, self.padding_idx)
926
+ self.layers = nn.ModuleList(
927
+ [LlamaDecoderLayer(config, layer_idx) for layer_idx in range(config.num_hidden_layers)]
928
+ )
929
+ self.norm = LlamaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
930
+ self.gradient_checkpointing = False
931
+
932
+ # Initialize weights and apply final processing
933
+ self.post_init()
934
+
935
+ def get_input_embeddings(self):
936
+ return self.embed_tokens
937
+
938
+ def set_input_embeddings(self, value):
939
+ self.embed_tokens = value
940
+
941
+ @add_start_docstrings_to_model_forward(LLAMA_INPUTS_DOCSTRING)
942
+ def forward(
943
+ self,
944
+ input_ids: torch.LongTensor = None,
945
+ attention_mask: Optional[torch.Tensor] = None,
946
+ position_ids: Optional[torch.LongTensor] = None,
947
+ past_key_values: Optional[List[torch.FloatTensor]] = None,
948
+ inputs_embeds: Optional[torch.FloatTensor] = None,
949
+ use_cache: Optional[bool] = None,
950
+ output_attentions: Optional[bool] = None,
951
+ output_hidden_states: Optional[bool] = None,
952
+ return_dict: Optional[bool] = None,
953
+ cache_position: Optional[torch.LongTensor] = None,
954
+ ) -> Union[Tuple, BaseModelOutputWithPast]:
955
+ output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
956
+ output_hidden_states = (
957
+ output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
958
+ )
959
+ use_cache = use_cache if use_cache is not None else self.config.use_cache
960
+ return_dict = return_dict if return_dict is not None else self.config.use_return_dict
961
+
962
+ if (input_ids is None) ^ (inputs_embeds is not None):
963
+ raise ValueError(
964
+ "You cannot specify both input_ids and inputs_embeds at the same time, and must specify either one"
965
+ )
966
+
967
+ if self.gradient_checkpointing and self.training and use_cache:
968
+ logger.warning_once(
969
+ "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`."
970
+ )
971
+ use_cache = False
972
+
973
+ if inputs_embeds is None:
974
+ inputs_embeds = self.embed_tokens(input_ids)
975
+
976
+ past_seen_tokens = 0
977
+ if use_cache: # kept for BC (cache positions)
978
+ if not isinstance(past_key_values, StaticCache):
979
+ past_key_values = DynamicCache.from_legacy_cache(past_key_values)
980
+ past_seen_tokens = past_key_values.get_seq_length()
981
+
982
+ if cache_position is None:
983
+ if isinstance(past_key_values, StaticCache):
984
+ raise ValueError("cache_position is a required argument when using StaticCache.")
985
+ cache_position = torch.arange(
986
+ past_seen_tokens, past_seen_tokens + inputs_embeds.shape[1], device=inputs_embeds.device
987
+ )
988
+
989
+ if position_ids is None:
990
+ position_ids = cache_position.unsqueeze(0)
991
+
992
+ causal_mask = self._update_causal_mask(attention_mask, inputs_embeds, cache_position, past_seen_tokens)
993
+
994
+ # embed positions
995
+ hidden_states = inputs_embeds
996
+
997
+ # decoder layers
998
+ all_hidden_states = () if output_hidden_states else None
999
+ all_self_attns = () if output_attentions else None
1000
+ next_decoder_cache = None
1001
+
1002
+ for decoder_layer in self.layers:
1003
+ if output_hidden_states:
1004
+ all_hidden_states += (hidden_states,)
1005
+
1006
+ if self.gradient_checkpointing and self.training:
1007
+ layer_outputs = self._gradient_checkpointing_func(
1008
+ decoder_layer.__call__,
1009
+ hidden_states,
1010
+ causal_mask,
1011
+ position_ids,
1012
+ past_key_values,
1013
+ output_attentions,
1014
+ use_cache,
1015
+ cache_position,
1016
+ )
1017
+ else:
1018
+ layer_outputs = decoder_layer(
1019
+ hidden_states,
1020
+ attention_mask=causal_mask,
1021
+ position_ids=position_ids,
1022
+ past_key_value=past_key_values,
1023
+ output_attentions=output_attentions,
1024
+ use_cache=use_cache,
1025
+ cache_position=cache_position,
1026
+ )
1027
+
1028
+ hidden_states = layer_outputs[0]
1029
+
1030
+ if use_cache:
1031
+ next_decoder_cache = layer_outputs[2 if output_attentions else 1]
1032
+
1033
+ if output_attentions:
1034
+ all_self_attns += (layer_outputs[1],)
1035
+
1036
+ hidden_states = self.norm(hidden_states)
1037
+
1038
+ # add hidden states from the last decoder layer
1039
+ if output_hidden_states:
1040
+ all_hidden_states += (hidden_states,)
1041
+
1042
+ next_cache = None
1043
+ if use_cache:
1044
+ next_cache = (
1045
+ next_decoder_cache.to_legacy_cache() if isinstance(next_decoder_cache, Cache) else next_decoder_cache
1046
+ )
1047
+ if not return_dict:
1048
+ return tuple(v for v in [hidden_states, next_cache, all_hidden_states, all_self_attns] if v is not None)
1049
+ return BaseModelOutputWithPast(
1050
+ last_hidden_state=hidden_states,
1051
+ past_key_values=next_cache,
1052
+ hidden_states=all_hidden_states,
1053
+ attentions=all_self_attns,
1054
+ )
1055
+
1056
+ def _update_causal_mask(
1057
+ self,
1058
+ attention_mask: torch.Tensor,
1059
+ input_tensor: torch.Tensor,
1060
+ cache_position: torch.Tensor,
1061
+ past_seen_tokens: int,
1062
+ ):
1063
+ # TODO: As of torch==2.2.0, the `attention_mask` passed to the model in `generate` is 2D and of dynamic length even when the static
1064
+ # KV cache is used. This is an issue for torch.compile which then recaptures cudagraphs at each decode steps due to the dynamic shapes.
1065
+ # (`recording cudagraph tree for symint key 13`, etc.), which is VERY slow. A workaround is `@torch.compiler.disable`, but this prevents using
1066
+ # `fullgraph=True`. See more context in https://github.com/huggingface/transformers/pull/29114
1067
+
1068
+ if self.config._attn_implementation == "flash_attention_2":
1069
+ if attention_mask is not None and 0.0 in attention_mask:
1070
+ return attention_mask
1071
+ return None
1072
+
1073
+ if self.config._attn_implementation == "sdpa":
1074
+ # For SDPA, when possible, we will rely on its `is_causal` argument instead of its `attn_mask` argument,
1075
+ # in order to dispatch on Flash Attention 2.
1076
+ if AttentionMaskConverter._ignore_causal_mask_sdpa(
1077
+ attention_mask, inputs_embeds=input_tensor, past_key_values_length=past_seen_tokens
1078
+ ):
1079
+ return None
1080
+
1081
+ dtype, device = input_tensor.dtype, input_tensor.device
1082
+ min_dtype = torch.finfo(dtype).min
1083
+ sequence_length = input_tensor.shape[1]
1084
+ if hasattr(getattr(self.layers[0], "self_attn", {}), "past_key_value"): # static cache
1085
+ target_length = self.config.max_position_embeddings
1086
+ else: # dynamic cache
1087
+ target_length = (
1088
+ attention_mask.shape[-1]
1089
+ if isinstance(attention_mask, torch.Tensor)
1090
+ else past_seen_tokens + sequence_length + 1
1091
+ )
1092
+
1093
+ causal_mask = torch.full((sequence_length, target_length), fill_value=min_dtype, dtype=dtype, device=device)
1094
+ if sequence_length != 1:
1095
+ causal_mask = torch.triu(causal_mask, diagonal=1)
1096
+ causal_mask *= torch.arange(target_length, device=device) > cache_position.reshape(-1, 1)
1097
+ causal_mask = causal_mask[None, None, :, :].expand(input_tensor.shape[0], 1, -1, -1)
1098
+ if attention_mask is not None:
1099
+ causal_mask = causal_mask.clone() # copy to contiguous memory for in-place edit
1100
+ if attention_mask.dim() == 2:
1101
+ mask_length = attention_mask.shape[-1]
1102
+ padding_mask = causal_mask[..., :mask_length].eq(0.0) * attention_mask[:, None, None, :].eq(0.0)
1103
+ causal_mask[..., :mask_length] = causal_mask[..., :mask_length].masked_fill(padding_mask, min_dtype)
1104
+ elif attention_mask.dim() == 4:
1105
+ # backwards compatibility: we allow passing a 4D attention mask shorter than the input length with
1106
+ # cache. In that case, the 4D attention mask attends to the newest tokens only.
1107
+ if attention_mask.shape[-2] < cache_position[0] + sequence_length:
1108
+ offset = cache_position[0]
1109
+ else:
1110
+ offset = 0
1111
+ mask_shape = attention_mask.shape
1112
+ mask_slice = (attention_mask.eq(0.0)).to(dtype=dtype) * min_dtype
1113
+ causal_mask[
1114
+ : mask_shape[0], : mask_shape[1], offset : mask_shape[2] + offset, : mask_shape[3]
1115
+ ] = mask_slice
1116
+
1117
+ if (
1118
+ self.config._attn_implementation == "sdpa"
1119
+ and attention_mask is not None
1120
+ and attention_mask.device.type == "cuda"
1121
+ ):
1122
+ # Attend to all tokens in fully masked rows in the causal_mask, for example the relevant first rows when
1123
+ # using left padding. This is required by F.scaled_dot_product_attention memory-efficient attention path.
1124
+ # Details: https://github.com/pytorch/pytorch/issues/110213
1125
+ causal_mask = AttentionMaskConverter._unmask_unattended(causal_mask, min_dtype)
1126
+
1127
+ return causal_mask
1128
+
1129
+
1130
+ class LlamaForCausalLM(LlamaPreTrainedModel):
1131
+ _tied_weights_keys = ["lm_head.weight"]
1132
+
1133
+ def __init__(self, config):
1134
+ super().__init__(config)
1135
+ self.model = LlamaModel(config)
1136
+ self.vocab_size = config.vocab_size
1137
+ self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
1138
+
1139
+ # Initialize weights and apply final processing
1140
+ self.post_init()
1141
+
1142
+ def get_input_embeddings(self):
1143
+ return self.model.embed_tokens
1144
+
1145
+ def set_input_embeddings(self, value):
1146
+ self.model.embed_tokens = value
1147
+
1148
+ def get_output_embeddings(self):
1149
+ return self.lm_head
1150
+
1151
+ def set_output_embeddings(self, new_embeddings):
1152
+ self.lm_head = new_embeddings
1153
+
1154
+ def set_decoder(self, decoder):
1155
+ self.model = decoder
1156
+
1157
+ def get_decoder(self):
1158
+ return self.model
1159
+
1160
+ @add_start_docstrings_to_model_forward(LLAMA_INPUTS_DOCSTRING)
1161
+ @replace_return_docstrings(output_type=CausalLMOutputWithPast, config_class=_CONFIG_FOR_DOC)
1162
+ def forward(
1163
+ self,
1164
+ input_ids: torch.LongTensor = None,
1165
+ attention_mask: Optional[torch.Tensor] = None,
1166
+ position_ids: Optional[torch.LongTensor] = None,
1167
+ past_key_values: Optional[List[torch.FloatTensor]] = None,
1168
+ inputs_embeds: Optional[torch.FloatTensor] = None,
1169
+ labels: Optional[torch.LongTensor] = None,
1170
+ use_cache: Optional[bool] = None,
1171
+ output_attentions: Optional[bool] = None,
1172
+ output_hidden_states: Optional[bool] = None,
1173
+ return_dict: Optional[bool] = None,
1174
+ cache_position: Optional[torch.LongTensor] = None,
1175
+ ) -> Union[Tuple, CausalLMOutputWithPast]:
1176
+ r"""
1177
+ Args:
1178
+ labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
1179
+ Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
1180
+ config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
1181
+ (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.
1182
+
1183
+ Returns:
1184
+
1185
+ Example:
1186
+
1187
+ ```python
1188
+ >>> from transformers import AutoTokenizer, LlamaForCausalLM
1189
+
1190
+ >>> model = LlamaForCausalLM.from_pretrained("meta-llama/Llama-2-7b-hf")
1191
+ >>> tokenizer = AutoTokenizer.from_pretrained("meta-llama/Llama-2-7b-hf")
1192
+
1193
+ >>> prompt = "Hey, are you conscious? Can you talk to me?"
1194
+ >>> inputs = tokenizer(prompt, return_tensors="pt")
1195
+
1196
+ >>> # Generate
1197
+ >>> generate_ids = model.generate(inputs.input_ids, max_length=30)
1198
+ >>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
1199
+ "Hey, are you conscious? Can you talk to me?\nI'm not conscious, but I can talk to you."
1200
+ ```"""
1201
+ output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
1202
+ output_hidden_states = (
1203
+ output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
1204
+ )
1205
+ return_dict = return_dict if return_dict is not None else self.config.use_return_dict
1206
+
1207
+ # decoder outputs consists of (dec_features, layer_state, dec_hidden, dec_attn)
1208
+ outputs = self.model(
1209
+ input_ids=input_ids,
1210
+ attention_mask=attention_mask,
1211
+ position_ids=position_ids,
1212
+ past_key_values=past_key_values,
1213
+ inputs_embeds=inputs_embeds,
1214
+ use_cache=use_cache,
1215
+ output_attentions=output_attentions,
1216
+ output_hidden_states=output_hidden_states,
1217
+ return_dict=return_dict,
1218
+ cache_position=cache_position,
1219
+ )
1220
+
1221
+ hidden_states = outputs[0]
1222
+ if self.config.pretraining_tp > 1:
1223
+ lm_head_slices = self.lm_head.weight.split(self.vocab_size // self.config.pretraining_tp, dim=0)
1224
+ logits = [F.linear(hidden_states, lm_head_slices[i]) for i in range(self.config.pretraining_tp)]
1225
+ logits = torch.cat(logits, dim=-1)
1226
+ else:
1227
+ logits = self.lm_head(hidden_states)
1228
+ logits = logits.float()
1229
+
1230
+ loss = None
1231
+ if labels is not None:
1232
+ # Shift so that tokens < n predict n
1233
+ shift_logits = logits[..., :-1, :].contiguous()
1234
+ shift_labels = labels[..., 1:].contiguous()
1235
+ # Flatten the tokens
1236
+ loss_fct = CrossEntropyLoss()
1237
+ shift_logits = shift_logits.view(-1, self.config.vocab_size)
1238
+ shift_labels = shift_labels.view(-1)
1239
+ # Enable model parallelism
1240
+ shift_labels = shift_labels.to(shift_logits.device)
1241
+ loss = loss_fct(shift_logits, shift_labels)
1242
+
1243
+ if not return_dict:
1244
+ output = (logits,) + outputs[1:]
1245
+ return (loss,) + output if loss is not None else output
1246
+
1247
+ return CausalLMOutputWithPast(
1248
+ loss=loss,
1249
+ logits=logits,
1250
+ past_key_values=outputs.past_key_values,
1251
+ hidden_states=outputs.hidden_states,
1252
+ attentions=outputs.attentions,
1253
+ )
1254
+
1255
+ def prepare_inputs_for_generation(
1256
+ self,
1257
+ input_ids,
1258
+ past_key_values=None,
1259
+ attention_mask=None,
1260
+ inputs_embeds=None,
1261
+ cache_position=None,
1262
+ use_cache=True,
1263
+ **kwargs,
1264
+ ):
1265
+ # With static cache, the `past_key_values` is None
1266
+ # TODO joao: standardize interface for the different Cache classes and remove of this if
1267
+ has_static_cache = False
1268
+ if past_key_values is None:
1269
+ past_key_values = getattr(getattr(self.model.layers[0], "self_attn", {}), "past_key_value", None)
1270
+ has_static_cache = past_key_values is not None
1271
+
1272
+ past_length = 0
1273
+ if past_key_values is not None:
1274
+ if isinstance(past_key_values, Cache):
1275
+ past_length = cache_position[0] if cache_position is not None else past_key_values.get_seq_length()
1276
+ max_cache_length = (
1277
+ torch.tensor(past_key_values.get_max_length(), device=input_ids.device)
1278
+ if past_key_values.get_max_length() is not None
1279
+ else None
1280
+ )
1281
+ cache_length = past_length if max_cache_length is None else torch.min(max_cache_length, past_length)
1282
+ # TODO joao: remove this `else` after `generate` prioritizes `Cache` objects
1283
+ else:
1284
+ cache_length = past_length = past_key_values[0][0].shape[2]
1285
+ max_cache_length = None
1286
+
1287
+ # Keep only the unprocessed tokens:
1288
+ # 1 - If the length of the attention_mask exceeds the length of input_ids, then we are in a setting where
1289
+ # some of the inputs are exclusively passed as part of the cache (e.g. when passing input_embeds as
1290
+ # input)
1291
+ if attention_mask is not None and attention_mask.shape[1] > input_ids.shape[1]:
1292
+ input_ids = input_ids[:, -(attention_mask.shape[1] - past_length) :]
1293
+ # 2 - If the past_length is smaller than input_ids', then input_ids holds all input tokens. We can discard
1294
+ # input_ids based on the past_length.
1295
+ elif past_length < input_ids.shape[1]:
1296
+ input_ids = input_ids[:, past_length:]
1297
+ # 3 - Otherwise (past_length >= input_ids.shape[1]), let's assume input_ids only has unprocessed tokens.
1298
+
1299
+ # If we are about to go beyond the maximum cache length, we need to crop the input attention mask.
1300
+ if (
1301
+ max_cache_length is not None
1302
+ and attention_mask is not None
1303
+ and cache_length + input_ids.shape[1] > max_cache_length
1304
+ ):
1305
+ attention_mask = attention_mask[:, -max_cache_length:]
1306
+
1307
+ position_ids = kwargs.get("position_ids", None)
1308
+ if attention_mask is not None and position_ids is None:
1309
+ # create position_ids on the fly for batch generation
1310
+ position_ids = attention_mask.long().cumsum(-1) - 1
1311
+ position_ids.masked_fill_(attention_mask == 0, 1)
1312
+ if past_key_values:
1313
+ position_ids = position_ids[:, -input_ids.shape[1] :]
1314
+
1315
+ # if `inputs_embeds` are passed, we only want to use them in the 1st generation step
1316
+ if inputs_embeds is not None and past_key_values is None:
1317
+ model_inputs = {"inputs_embeds": inputs_embeds}
1318
+ else:
1319
+ # The `contiguous()` here is necessary to have a static stride during decoding. torchdynamo otherwise
1320
+ # recompiles graphs as the stride of the inputs is a guard. Ref: https://github.com/huggingface/transformers/pull/29114
1321
+ # TODO: use `next_tokens` directly instead.
1322
+ model_inputs = {"input_ids": input_ids.contiguous()}
1323
+
1324
+ input_length = position_ids.shape[-1] if position_ids is not None else input_ids.shape[-1]
1325
+ if cache_position is None:
1326
+ cache_position = torch.arange(past_length, past_length + input_length, device=input_ids.device)
1327
+ elif use_cache:
1328
+ cache_position = cache_position[-input_length:]
1329
+
1330
+ if has_static_cache:
1331
+ past_key_values = None
1332
+
1333
+ model_inputs.update(
1334
+ {
1335
+ "position_ids": position_ids,
1336
+ "cache_position": cache_position,
1337
+ "past_key_values": past_key_values,
1338
+ "use_cache": use_cache,
1339
+ "attention_mask": attention_mask,
1340
+ }
1341
+ )
1342
+ return model_inputs
1343
+
1344
+ @staticmethod
1345
+ def _reorder_cache(past_key_values, beam_idx):
1346
+ reordered_past = ()
1347
+ for layer_past in past_key_values:
1348
+ reordered_past += (
1349
+ tuple(past_state.index_select(0, beam_idx.to(past_state.device)) for past_state in layer_past),
1350
+ )
1351
+ return reordered_past
1352
+
1353
+
1354
+ @add_start_docstrings(
1355
+ """
1356
+ The LLaMa Model transformer with a sequence classification head on top (linear layer).
1357
+
1358
+ [`LlamaForSequenceClassification`] uses the last token in order to do the classification, as other causal models
1359
+ (e.g. GPT-2) do.
1360
+
1361
+ Since it does classification on the last token, it requires to know the position of the last token. If a
1362
+ `pad_token_id` is defined in the configuration, it finds the last token that is not a padding token in each row. If
1363
+ no `pad_token_id` is defined, it simply takes the last value in each row of the batch. Since it cannot guess the
1364
+ padding tokens when `inputs_embeds` are passed instead of `input_ids`, it does the same (take the last value in
1365
+ each row of the batch).
1366
+ """,
1367
+ LLAMA_START_DOCSTRING,
1368
+ )
1369
+ class LlamaForSequenceClassification(LlamaPreTrainedModel):
1370
+ def __init__(self, config):
1371
+ super().__init__(config)
1372
+ self.num_labels = config.num_labels
1373
+ self.model = LlamaModel(config)
1374
+ self.score = nn.Linear(config.hidden_size, self.num_labels, bias=False)
1375
+
1376
+ # Initialize weights and apply final processing
1377
+ self.post_init()
1378
+
1379
+ def get_input_embeddings(self):
1380
+ return self.model.embed_tokens
1381
+
1382
+ def set_input_embeddings(self, value):
1383
+ self.model.embed_tokens = value
1384
+
1385
+ @add_start_docstrings_to_model_forward(LLAMA_INPUTS_DOCSTRING)
1386
+ def forward(
1387
+ self,
1388
+ input_ids: torch.LongTensor = None,
1389
+ attention_mask: Optional[torch.Tensor] = None,
1390
+ position_ids: Optional[torch.LongTensor] = None,
1391
+ past_key_values: Optional[List[torch.FloatTensor]] = None,
1392
+ inputs_embeds: Optional[torch.FloatTensor] = None,
1393
+ labels: Optional[torch.LongTensor] = None,
1394
+ use_cache: Optional[bool] = None,
1395
+ output_attentions: Optional[bool] = None,
1396
+ output_hidden_states: Optional[bool] = None,
1397
+ return_dict: Optional[bool] = None,
1398
+ ) -> Union[Tuple, SequenceClassifierOutputWithPast]:
1399
+ r"""
1400
+ labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
1401
+ Labels for computing the sequence classification/regression loss. Indices should be in `[0, ...,
1402
+ config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If
1403
+ `config.num_labels > 1` a classification loss is computed (Cross-Entropy).
1404
+ """
1405
+ return_dict = return_dict if return_dict is not None else self.config.use_return_dict
1406
+
1407
+ transformer_outputs = self.model(
1408
+ input_ids,
1409
+ attention_mask=attention_mask,
1410
+ position_ids=position_ids,
1411
+ past_key_values=past_key_values,
1412
+ inputs_embeds=inputs_embeds,
1413
+ use_cache=use_cache,
1414
+ output_attentions=output_attentions,
1415
+ output_hidden_states=output_hidden_states,
1416
+ return_dict=return_dict,
1417
+ )
1418
+ hidden_states = transformer_outputs[0]
1419
+ logits = self.score(hidden_states)
1420
+
1421
+ if input_ids is not None:
1422
+ batch_size = input_ids.shape[0]
1423
+ else:
1424
+ batch_size = inputs_embeds.shape[0]
1425
+
1426
+ if self.config.pad_token_id is None and batch_size != 1:
1427
+ raise ValueError("Cannot handle batch sizes > 1 if no padding token is defined.")
1428
+ if self.config.pad_token_id is None:
1429
+ sequence_lengths = -1
1430
+ else:
1431
+ if input_ids is not None:
1432
+ # if no pad token found, use modulo instead of reverse indexing for ONNX compatibility
1433
+ sequence_lengths = torch.eq(input_ids, self.config.pad_token_id).int().argmax(-1) - 1
1434
+ sequence_lengths = sequence_lengths % input_ids.shape[-1]
1435
+ sequence_lengths = sequence_lengths.to(logits.device)
1436
+ else:
1437
+ sequence_lengths = -1
1438
+
1439
+ pooled_logits = logits[torch.arange(batch_size, device=logits.device), sequence_lengths]
1440
+
1441
+ loss = None
1442
+ if labels is not None:
1443
+ labels = labels.to(logits.device)
1444
+ if self.config.problem_type is None:
1445
+ if self.num_labels == 1:
1446
+ self.config.problem_type = "regression"
1447
+ elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int):
1448
+ self.config.problem_type = "single_label_classification"
1449
+ else:
1450
+ self.config.problem_type = "multi_label_classification"
1451
+
1452
+ if self.config.problem_type == "regression":
1453
+ loss_fct = MSELoss()
1454
+ if self.num_labels == 1:
1455
+ loss = loss_fct(pooled_logits.squeeze(), labels.squeeze())
1456
+ else:
1457
+ loss = loss_fct(pooled_logits, labels)
1458
+ elif self.config.problem_type == "single_label_classification":
1459
+ loss_fct = CrossEntropyLoss()
1460
+ loss = loss_fct(pooled_logits.view(-1, self.num_labels), labels.view(-1))
1461
+ elif self.config.problem_type == "multi_label_classification":
1462
+ loss_fct = BCEWithLogitsLoss()
1463
+ loss = loss_fct(pooled_logits, labels)
1464
+ if not return_dict:
1465
+ output = (pooled_logits,) + transformer_outputs[1:]
1466
+ return ((loss,) + output) if loss is not None else output
1467
+
1468
+ return SequenceClassifierOutputWithPast(
1469
+ loss=loss,
1470
+ logits=pooled_logits,
1471
+ past_key_values=transformer_outputs.past_key_values,
1472
+ hidden_states=transformer_outputs.hidden_states,
1473
+ attentions=transformer_outputs.attentions,
1474
+ )
1475
+
1476
+
1477
+ @add_start_docstrings(
1478
+ """
1479
+ The Llama Model transformer with a span classification head on top for extractive question-answering tasks like
1480
+ SQuAD (a linear layer on top of the hidden-states output to compute `span start logits` and `span end logits`).
1481
+ """,
1482
+ LLAMA_START_DOCSTRING,
1483
+ )
1484
+ class LlamaForQuestionAnswering(LlamaPreTrainedModel):
1485
+ base_model_prefix = "transformer"
1486
+
1487
+ # Copied from transformers.models.bloom.modeling_bloom.BloomForQuestionAnswering.__init__ with Bloom->Llama
1488
+ def __init__(self, config):
1489
+ super().__init__(config)
1490
+ self.transformer = LlamaModel(config)
1491
+ self.qa_outputs = nn.Linear(config.hidden_size, 2)
1492
+
1493
+ # Initialize weights and apply final processing
1494
+ self.post_init()
1495
+
1496
+ def get_input_embeddings(self):
1497
+ return self.transformer.embed_tokens
1498
+
1499
+ def set_input_embeddings(self, value):
1500
+ self.transformer.embed_tokens = value
1501
+
1502
+ @add_start_docstrings_to_model_forward(LLAMA_INPUTS_DOCSTRING)
1503
+ def forward(
1504
+ self,
1505
+ input_ids: Optional[torch.LongTensor] = None,
1506
+ attention_mask: Optional[torch.FloatTensor] = None,
1507
+ position_ids: Optional[torch.LongTensor] = None,
1508
+ past_key_values: Optional[List[torch.FloatTensor]] = None,
1509
+ inputs_embeds: Optional[torch.FloatTensor] = None,
1510
+ start_positions: Optional[torch.LongTensor] = None,
1511
+ end_positions: Optional[torch.LongTensor] = None,
1512
+ output_attentions: Optional[bool] = None,
1513
+ output_hidden_states: Optional[bool] = None,
1514
+ return_dict: Optional[bool] = None,
1515
+ ) -> Union[Tuple, QuestionAnsweringModelOutput]:
1516
+ r"""
1517
+ start_positions (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
1518
+ Labels for position (index) of the start of the labelled span for computing the token classification loss.
1519
+ Positions are clamped to the length of the sequence (`sequence_length`). Position outside of the sequence
1520
+ are not taken into account for computing the loss.
1521
+ end_positions (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
1522
+ Labels for position (index) of the end of the labelled span for computing the token classification loss.
1523
+ Positions are clamped to the length of the sequence (`sequence_length`). Position outside of the sequence
1524
+ are not taken into account for computing the loss.
1525
+ """
1526
+ return_dict = return_dict if return_dict is not None else self.config.use_return_dict
1527
+
1528
+ outputs = self.transformer(
1529
+ input_ids,
1530
+ attention_mask=attention_mask,
1531
+ position_ids=position_ids,
1532
+ past_key_values=past_key_values,
1533
+ inputs_embeds=inputs_embeds,
1534
+ output_attentions=output_attentions,
1535
+ output_hidden_states=output_hidden_states,
1536
+ return_dict=return_dict,
1537
+ )
1538
+
1539
+ sequence_output = outputs[0]
1540
+
1541
+ logits = self.qa_outputs(sequence_output)
1542
+ start_logits, end_logits = logits.split(1, dim=-1)
1543
+ start_logits = start_logits.squeeze(-1).contiguous()
1544
+ end_logits = end_logits.squeeze(-1).contiguous()
1545
+
1546
+ total_loss = None
1547
+ if start_positions is not None and end_positions is not None:
1548
+ # If we are on multi-GPU, split add a dimension
1549
+ if len(start_positions.size()) > 1:
1550
+ start_positions = start_positions.squeeze(-1).to(start_logits.device)
1551
+ if len(end_positions.size()) > 1:
1552
+ end_positions = end_positions.squeeze(-1).to(end_logits.device)
1553
+ # sometimes the start/end positions are outside our model inputs, we ignore these terms
1554
+ ignored_index = start_logits.size(1)
1555
+ start_positions = start_positions.clamp(0, ignored_index)
1556
+ end_positions = end_positions.clamp(0, ignored_index)
1557
+
1558
+ loss_fct = CrossEntropyLoss(ignore_index=ignored_index)
1559
+ start_loss = loss_fct(start_logits, start_positions)
1560
+ end_loss = loss_fct(end_logits, end_positions)
1561
+ total_loss = (start_loss + end_loss) / 2
1562
+
1563
+ if not return_dict:
1564
+ output = (start_logits, end_logits) + outputs[2:]
1565
+ return ((total_loss,) + output) if total_loss is not None else output
1566
+
1567
+ return QuestionAnsweringModelOutput(
1568
+ loss=total_loss,
1569
+ start_logits=start_logits,
1570
+ end_logits=end_logits,
1571
+ hidden_states=outputs.hidden_states,
1572
+ attentions=outputs.attentions,
1573
+ )