File size: 33,858 Bytes
f225bf9 bbd070b f225bf9 |
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 |
# From: https://github.com/huggingface/transformers/blob/main/src/transformers/models/t5/modeling_t5.py
from dataclasses import dataclass
import copy
import math
from typing import Optional, Tuple, Union
import torch
from torch import nn
from torch.nn import CrossEntropyLoss
import torch.nn.functional as F
from transformers.modeling_utils import ModuleUtilsMixin
from transformers.modeling_outputs import ModelOutput, Seq2SeqModelOutput, BaseModelOutput
from transformers import PreTrainedModel
try:
from .rms_norm import fast_rms_layernorm
except ImportError:
fast_rms_layernorm = None
try:
from .cross_entropy_loss import fast_cross_entropy_loss
except ImportError:
fast_cross_entropy_loss = None
try:
from .flash_attention_v2_bias import attention as flash_attention_triton
except ImportError:
fast_cross_entropy_loss = None
try:
from .gated_mlp import gated_mlp
except ImportError:
gated_mlp = None
try:
#from flash_attn import flash_attn_kvpacked_func, flash_attn_func
from .fa2_compilable import flash_attn_kvpacked_func, flash_attn_func
except ImportError:
flash_attn_kvpacked_func, flash_attn_func = None, None
from .attn_ref import attn_ref
from .configuration_flash_t5 import FlashT5Config
from .positional_encoding import ALiBiPositionalEncoding, RelativePositionalEncoding, RotaryPositionalEncoding
@dataclass
class EncoderOutput(ModelOutput):
hidden_states: torch.FloatTensor = None
attention_mask: torch.FloatTensor = None
@dataclass
class Seq2SeqLMOutput(ModelOutput):
loss: torch.FloatTensor = None
logits: torch.FloatTensor = None
encoder_outputs: EncoderOutput = None
class FlashT5CrossEntropyLoss(nn.Module):
def __init__(self, z_loss_factor=0.0, label_smoothing=0.0, use_triton_crossentropy=False):
super().__init__()
if use_triton_crossentropy and fast_cross_entropy_loss is None:
raise ImportError("fast_cross_entropy_loss is not available")
self.use_triton_crossentropy = use_triton_crossentropy
self.z_loss_factor = z_loss_factor
self.cross_entropy_loss = nn.CrossEntropyLoss(label_smoothing=label_smoothing)
def compute_zloss(self, logits: torch.Tensor, z_loss: float):
logits_sum = torch.logsumexp(logits, dim=-1, keepdim=True)
log_z = torch.squeeze(logits_sum, axis=-1)
total_z_loss = z_loss * torch.square(log_z)
return total_z_loss.mean()
def forward(self, logits, labels):
if self.use_triton_crossentropy:
return fast_cross_entropy_loss(logits, labels, z_loss_factor=self.z_loss_factor)
# use standard method
batch, seq_len, d = logits.shape
logits_flatten = logits.float().view(batch*seq_len, d) # Must cast to float32 for numerical stability
labels_flatten = labels.view(-1)
loss = self.cross_entropy_loss(logits_flatten, labels_flatten)
z_loss = 0.0
if self.z_loss_factor != 0.0:
z_loss = self.compute_zloss(logits_flatten[labels_flatten != -100],
z_loss=self.z_loss_factor)
return loss, z_loss
class FlashT5LayerNorm(nn.Module):
def __init__(self, hidden_size, eps=1e-6, use_triton_layernorm=False):
"""
Construct a layernorm module in the T5 style. No bias and no subtraction of mean.
"""
super().__init__()
if use_triton_layernorm and fast_rms_layernorm is None:
raise ImportError("fast_rms_layernorm is not available")
self.use_triton_layernorm = use_triton_layernorm
self.weight = nn.Parameter(torch.ones(hidden_size))
self.variance_epsilon = eps
def forward(self, hidden_states):
if self.use_triton_layernorm:
return fast_rms_layernorm(hidden_states, self.weight, self.variance_epsilon)
# T5 uses a layer_norm which only scales and doesn't shift, which is also known as Root Mean
# Square Layer Normalization https://arxiv.org/abs/1910.07467 thus varience is calculated
# w/o mean and there is no bias. Additionally we want to make sure that the accumulation for
# half-precision inputs is done in fp32
variance = hidden_states.to(torch.float32).pow(2).mean(-1, keepdim=True)
hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
# convert into half-precision if necessary
if self.weight.dtype in [torch.float16, torch.bfloat16]:
hidden_states = hidden_states.to(self.weight.dtype)
return self.weight * hidden_states
class FlashT5DenseAct(nn.Module):
def __init__(self, config: FlashT5Config):
super().__init__()
self.wi = nn.Linear(config.d_model, config.d_ff, bias=False)
self.dropout = nn.Dropout(config.dropout_rate)
self.act = torch.nn.GELU(approximate='tanh') if config.use_gelu_act else torch.nn.ReLU()
def forward(self, hidden_states):
hidden_states = self.wi(hidden_states)
hidden_states = self.act(hidden_states)
hidden_states = self.dropout(hidden_states)
if (
isinstance(self.wo.weight, torch.Tensor)
and hidden_states.dtype != self.wo.weight.dtype
and self.wo.weight.dtype != torch.int8
):
hidden_states = hidden_states.to(self.wo.weight.dtype)
return hidden_states
class FlashT5DenseGatedAct(nn.Module):
def __init__(self, config: FlashT5Config):
super().__init__()
self.wi_0 = nn.Linear(config.d_model, config.d_ff, bias=False)
self.wi_1 = nn.Linear(config.d_model, config.d_ff, bias=False)
self.dropout = nn.Dropout(config.dropout_rate)
self.act = torch.nn.GELU(approximate='tanh') if config.use_gelu_act else torch.nn.ReLU()
self.use_triton_gated_mlp = config.use_triton_gated_mlp
if self.use_triton_gated_mlp and gated_mlp is None:
raise ImportError("gated_mlp is not available")
self.use_gelu_act = config.use_gelu_act
def forward(self, hidden_states):
if self.use_triton_gated_mlp:
return gated_mlp(hidden_states, self.wi_0.weight, self.wi_1.weight, self.use_gelu_act)
hidden_act = self.act(self.wi_0(hidden_states))
hidden_linear = self.wi_1(hidden_states)
hidden_states = hidden_act * hidden_linear
hidden_states = self.dropout(hidden_states)
return hidden_states
class FlashT5LayerFF(nn.Module):
def __init__(self, config: FlashT5Config):
super().__init__()
if config.use_glu_mlp:
self.act = FlashT5DenseGatedAct(config)
else:
self.act = FlashT5DenseAct(config)
self.layer_norm = FlashT5LayerNorm(config.d_model, eps=config.layer_norm_epsilon, use_triton_layernorm=config.use_triton_layernorm)
self.wo = nn.Linear(config.d_ff, config.d_model, bias=False)
self.dropout = nn.Dropout(config.dropout_rate)
def forward(self, hidden_states):
forwarded_states = self.layer_norm(hidden_states).type_as(hidden_states)
forwarded_states = self.act(forwarded_states)
forwarded_states = self.wo(forwarded_states)
hidden_states = hidden_states + self.dropout(forwarded_states)
return hidden_states
class FlashT5Attention(nn.Module, ModuleUtilsMixin):
def __init__(self, config: FlashT5Config, has_positional_encoding=False, is_causal=False):
super().__init__()
self.is_decoder = config.is_decoder
self.has_positional_encoding = has_positional_encoding
self.is_causal = is_causal
self.relative_attention_num_buckets = config.relative_attention_num_buckets
self.relative_attention_max_distance = config.relative_attention_max_distance
self.d_model = config.d_model
self.key_value_proj_dim = config.d_kv
self.n_heads = config.num_heads
self.p_dropout = config.attention_dropout_rate
self.inner_dim = self.n_heads * self.key_value_proj_dim
self.use_flash_attention = config.use_flash_attention
self.position_encoding_type = config.position_encoding_type
self.max_sequence_length = config.max_sequence_length
self.softmax_scale = 1.0/math.sqrt(self.n_heads)
self.use_full_bias_size = config.use_full_bias_size
if self.use_flash_attention == "triton" and flash_attention_triton is None:
raise ImportError("flash_attention_triton is not available")
elif self.use_flash_attention == "fa2" and flash_attn_func is None:
raise ImportError("Flash Attention 2 is not available")
assert (self.p_dropout == 0.0) or (self.use_flash_attention != "triton"), "Triton attention does not support dropout"
self.pe_encoding = None
if self.position_encoding_type == "ALiBi" and has_positional_encoding:
# build alibi matrix with an upper bound on seq length
self.pe_encoding = ALiBiPositionalEncoding(self.max_sequence_length, self.n_heads, config.alibi_mode, config.use_randomized_position_encoding)
elif self.position_encoding_type == "t5" and has_positional_encoding:
self.pe_encoding = RelativePositionalEncoding(self.relative_attention_num_buckets, self.relative_attention_max_distance, self.n_heads, self.max_sequence_length, config.use_randomized_position_encoding)
elif self.position_encoding_type == "RoPE":
self.pe_encoding = RotaryPositionalEncoding(int(self.key_value_proj_dim * config.rotary_emb_fraction), self.max_sequence_length, config.rotary_base, config.rotary_interleaved, config.rotary_scale_base, config.use_randomized_position_encoding)
self.Wq = nn.Linear(self.d_model, self.inner_dim, bias=False)
self.Wk = nn.Linear(self.d_model, self.inner_dim, bias=False)
self.Wv = nn.Linear(self.d_model, self.inner_dim, bias=False)
self.o = nn.Linear(self.inner_dim, self.d_model, bias=False)
def forward(
self,
hidden_states,
mask=None,
key_value_states=None,
position_bias=None,
):
"""
Self-attention (if key_value_states is None) or attention over source sentence (provided by key_value_states).
"""
# Input is (batch_size, seq_length, dim)
# Mask is (batch_size, key_length) (non-causal) or (batch_size, key_length, key_length)
batch_size, seq_length = hidden_states.shape[:2]
key_length = seq_length if key_value_states is None else key_value_states.shape[1]
q = self.Wq(hidden_states)
if key_value_states is None:
k = self.Wk(hidden_states)
v = self.Wv(hidden_states)
else:
k = self.Wk(key_value_states)
v = self.Wv(key_value_states)
q = q.view(batch_size, seq_length, self.n_heads, self.key_value_proj_dim)
k = k.view(batch_size, key_length, self.n_heads, self.key_value_proj_dim)
v = v.view(batch_size, key_length, self.n_heads, self.key_value_proj_dim)
if position_bias is None and self.pe_encoding is not None:
q, k, v, position_bias = self.pe_encoding(q, k, v)
if position_bias is not None and self.use_full_bias_size and (self.use_flash_attention == "fa2" or self.use_flash_attention == "triton"):
position_bias = position_bias.expand(q.shape[0], q.shape[2], q.shape[1], k.shape[1]).contiguous()
if self.use_flash_attention == "fa2":
output = flash_attn_func(q, k, v, dropout_p=self.p_dropout, softmax_scale=self.softmax_scale, attn_bias=position_bias, causal=self.is_causal)
elif self.use_flash_attention == "triton":
q = q.permute(0, 2, 1, 3)
k = k.permute(0, 2, 1, 3)
v = v.permute(0, 2, 1, 3)
output = flash_attention_triton(q, k, v, position_bias, self.is_causal, self.softmax_scale)
output = output.permute(0, 2, 1, 3)
else: # use flash attention
q = q.permute(0, 2, 1, 3)
k = k.permute(0, 2, 1, 3)
v = v.permute(0, 2, 1, 3)
output = attn_ref(q, k, v, position_bias, dropout_p=self.p_dropout, sm_scale=self.softmax_scale, causal=self.is_causal)
output = output.permute(0, 2, 1, 3)
output = self.o(output.reshape(output.shape[0], output.shape[1], self.inner_dim))
return (output, position_bias)
class FlashT5LayerSelfAttention(nn.Module):
def __init__(self, config, has_positional_encoding=False):
super().__init__()
self.self_attention = FlashT5Attention(config, has_positional_encoding=has_positional_encoding, is_causal=config.is_decoder)
self.layer_norm = FlashT5LayerNorm(config.d_model, eps=config.layer_norm_epsilon, use_triton_layernorm=config.use_triton_layernorm)
self.dropout = nn.Dropout(config.dropout_rate)
def forward(
self,
hidden_states,
attention_mask=None,
position_bias=None,
):
normed_hidden_states = self.layer_norm(hidden_states).type_as(hidden_states)
attention_output = self.self_attention(
normed_hidden_states,
mask=attention_mask,
position_bias=position_bias,
)
hidden_states = hidden_states + self.dropout(attention_output[0])
outputs = (hidden_states,) + attention_output[1:]
return outputs
class FlashT5LayerCrossAttention(nn.Module):
def __init__(self, config):
super().__init__()
self.cross_attention = FlashT5Attention(config, has_positional_encoding=False)
self.layer_norm = FlashT5LayerNorm(config.d_model, eps=config.layer_norm_epsilon, use_triton_layernorm=config.use_triton_layernorm)
self.dropout = nn.Dropout(config.dropout_rate)
def forward(
self,
hidden_states,
key_value_states,
attention_mask=None,
position_bias=None,
):
normed_hidden_states = self.layer_norm(hidden_states)
attention_output = self.cross_attention(
normed_hidden_states,
mask=attention_mask,
key_value_states=key_value_states,
position_bias=position_bias,
)
layer_output = hidden_states + self.dropout(attention_output[0])
outputs = (layer_output,) + attention_output[1:]
return outputs
class FlashT5Block(nn.Module):
def __init__(self, config, has_positional_encoding=False):
super().__init__()
self.is_decoder = config.is_decoder
self.self_attention_layer = FlashT5LayerSelfAttention(config, has_positional_encoding=has_positional_encoding)
if self.is_decoder:
self.cross_attention_layer = FlashT5LayerCrossAttention(config)
self.ff_layer = FlashT5LayerFF(config)
def forward(
self,
hidden_states,
attention_mask=None,
position_bias=None,
encoder_hidden_states=None,
encoder_attention_mask=None,
encoder_decoder_position_bias=None,
):
self_attention_outputs = self.self_attention_layer(
hidden_states,
attention_mask=attention_mask,
position_bias=position_bias,
)
hidden_states = self_attention_outputs[0]
attention_outputs = self_attention_outputs[1:] # Relative position weights
if self.is_decoder and encoder_hidden_states is not None:
cross_attention_outputs = self.cross_attention_layer(
hidden_states,
key_value_states=encoder_hidden_states,
attention_mask=encoder_attention_mask,
position_bias=encoder_decoder_position_bias,
)
hidden_states = cross_attention_outputs[0]
# Keep relative position weights
attention_outputs = attention_outputs + cross_attention_outputs[1:]
# Apply Feed Forward layer
hidden_states = self.ff_layer(hidden_states)
outputs = (hidden_states,) + attention_outputs
return outputs # hidden-states, (self-attention position bias), (cross-attention position bias)
class FlashT5Stack(nn.Module, ModuleUtilsMixin):
def __init__(self, config, embed_tokens):
super().__init__()
assert embed_tokens is not None
self.config = config
self.embed_tokens = embed_tokens
self.is_decoder = config.is_decoder
self.use_flash_attention = config.use_flash_attention
self.block = nn.ModuleList(
[FlashT5Block(config, has_positional_encoding=bool(i == 0)) for i in range(config.num_layers)]
)
self.final_layer_norm = FlashT5LayerNorm(config.d_model, eps=config.layer_norm_epsilon, use_triton_layernorm=config.use_triton_layernorm)
self.dropout = nn.Dropout(config.dropout_rate)
def forward(
self,
input_ids=None,
attention_mask=None,
encoder_hidden_states=None,
encoder_attention_mask=None,
inputs_embeds=None,
head_mask=None,
cross_attn_head_mask=None,
past_key_values=None,
use_cache=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None) -> BaseModelOutput:
input_shape = input_ids.size()
batch_size, seq_length = input_shape
if inputs_embeds is None:
inputs_embeds = self.embed_tokens(input_ids)
if torch.is_autocast_enabled() and input_ids.device.type == 'cuda':
inputs_embeds = inputs_embeds.to(torch.get_autocast_gpu_dtype())
# Masking
if attention_mask is None:
attention_mask = torch.ones(batch_size, seq_length, device=inputs_embeds.device, dtype=torch.bool)
if self.is_decoder and encoder_attention_mask is None and encoder_hidden_states is not None:
encoder_seq_length = encoder_hidden_states.shape[1]
encoder_attention_mask = torch.ones(
batch_size, encoder_seq_length, device=inputs_embeds.device, dtype=torch.bool
)
position_bias = None
encoder_decoder_position_bias = None
hidden_states = self.dropout(inputs_embeds)
for _, layer_module in enumerate(self.block):
layer_outputs = layer_module(
hidden_states,
attention_mask=attention_mask,
position_bias=position_bias,
encoder_hidden_states=encoder_hidden_states,
encoder_attention_mask=encoder_attention_mask,
encoder_decoder_position_bias=encoder_decoder_position_bias,
)
# We share the position biases between the layers - the first layer store them
position_bias = layer_outputs[1]
if self.is_decoder and encoder_hidden_states is not None:
encoder_decoder_position_bias = layer_outputs[2]
hidden_states = layer_outputs[0]
hidden_states = self.final_layer_norm(hidden_states).type_as(hidden_states)
hidden_states = self.dropout(hidden_states)
return BaseModelOutput(
last_hidden_state=hidden_states
)
class FlashT5PreTrainedModel(PreTrainedModel):
"""
An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
models.
"""
config_class = FlashT5Config
base_model_prefix = "transformer"
is_parallelizable = False
supports_gradient_checkpointing = True
_no_split_modules = ["FlashT5Block"]
_keep_in_fp32_modules = []
def _init_weights(self, module):
factor = self.config.initializer_factor # Used for testing weights initialization
if isinstance(module, FlashT5LayerNorm):
module.weight.data.fill_(factor * 1.0)
elif isinstance(module, (FlashT5ForConditionalGeneration)):
module.shared.weight.data.normal_(mean=0.0, std=factor * 1.0)
if hasattr(module, "lm_head") and not self.config.tie_word_embeddings:
module.lm_head.weight.data.normal_(mean=0.0, std=factor * self.config.d_model ** -0.5)
elif isinstance(module, FlashT5DenseGatedAct):
d_ff, d_model = module.wi_0.weight.data.size()
module.wi_0.weight.data.normal_(mean=0.0, std=factor * ((d_model) ** -0.5))
module.wi_1.weight.data.normal_(mean=0.0, std=factor * ((d_model) ** -0.5))
elif isinstance(module, FlashT5LayerFF):
d_ff, d_model = module.wo.weight.data.size()
module.wo.weight.data.normal_(mean=0.0, std=factor * ((d_ff) ** -0.5))
elif isinstance(module, FlashT5Attention):
d_model = self.config.d_model
key_value_proj_dim = self.config.d_kv
n_heads = self.config.num_heads
module.Wq.weight.data.normal_(mean=0.0, std=factor * ((d_model * key_value_proj_dim) ** -0.5))
module.Wk.weight.data.normal_(mean=0.0, std=factor * (d_model**-0.5))
module.Wv.weight.data.normal_(mean=0.0, std=factor * (d_model**-0.5))
module.o.weight.data.normal_(mean=0.0, std=factor * ((n_heads * key_value_proj_dim) ** -0.5))
if module.has_positional_encoding:
if hasattr(module.pe_encoding, "relative_attention_bias"):
module.pe_encoding.relative_attention_bias.weight.data.normal_(mean=0.0, std=factor * ((d_model) ** -0.5))
def _shift_right(self, input_ids):
decoder_start_token_id = self.config.decoder_start_token_id
pad_token_id = self.config.pad_token_id
shifted_input_ids = input_ids.new_zeros(input_ids.shape)
shifted_input_ids[..., 1:] = input_ids[..., :-1].clone()
shifted_input_ids[..., 0] = decoder_start_token_id
# replace possible -100 values in labels by `pad_token_id`
shifted_input_ids.masked_fill_(shifted_input_ids == -100, pad_token_id)
return shifted_input_ids
class FlashT5Model(FlashT5PreTrainedModel):
def __init__(self, config: FlashT5Config):
super().__init__(config)
self.shared = nn.Embedding(config.vocab_size, config.d_model)
encoder_config = copy.deepcopy(config)
encoder_config.is_decoder = False
encoder_config.use_cache = False
encoder_config.is_encoder_decoder = False
self.encoder = FlashT5Stack(encoder_config, self.shared)
decoder_config = copy.deepcopy(config)
decoder_config.is_decoder = True
decoder_config.is_encoder_decoder = False
decoder_config.num_layers = config.num_decoder_layers
self.decoder = FlashT5Stack(decoder_config, self.shared)
# Initialize weights and apply final processing
self.post_init()
# Model parallel
self.model_parallel = False
self.device_map = None
def get_input_embeddings(self):
return self.shared
def set_input_embeddings(self, new_embeddings):
self.shared = new_embeddings
self.encoder.set_input_embeddings(new_embeddings)
self.decoder.set_input_embeddings(new_embeddings)
def get_encoder(self):
return self.encoder
def get_decoder(self):
return self.decoder
def forward(
self,
input_ids: Optional[torch.LongTensor] = None,
attention_mask: Optional[torch.FloatTensor] = None,
decoder_input_ids: Optional[torch.LongTensor] = None,
decoder_attention_mask: Optional[torch.BoolTensor] = None,
head_mask: Optional[torch.FloatTensor] = None,
decoder_head_mask: Optional[torch.FloatTensor] = None,
cross_attn_head_mask: Optional[torch.Tensor] = None,
encoder_outputs: Optional[Tuple[Tuple[torch.FloatTensor]]] = None,
past_key_values: Optional[Tuple[Tuple[torch.FloatTensor]]] = None,
inputs_embeds: Optional[torch.Tensor] = None,
decoder_inputs_embeds: Optional[torch.Tensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
) -> Union[Tuple[torch.FloatTensor], Seq2SeqModelOutput]:
# Encode if needed (training, first prediction pass)
if encoder_outputs is None:
encoder_outputs = self.encoder(
input_ids=input_ids,
attention_mask=attention_mask,
inputs_embeds=inputs_embeds
)
hidden_states = encoder_outputs[0]
# Decode
decoder_outputs = self.decoder(
input_ids=decoder_input_ids,
attention_mask=decoder_attention_mask,
inputs_embeds=decoder_inputs_embeds,
encoder_hidden_states=hidden_states,
encoder_attention_mask=attention_mask
)
return Seq2SeqModelOutput(
last_hidden_state=decoder_outputs.last_hidden_state,
decoder_hidden_states=decoder_outputs.hidden_states,
encoder_last_hidden_state=encoder_outputs.last_hidden_state,
encoder_hidden_states=encoder_outputs.hidden_states,
)
class FlashT5ForConditionalGeneration(FlashT5PreTrainedModel):
def __init__(self, config: FlashT5Config):
super().__init__(config)
config.is_encoder_decoder = False
assert not config.tie_word_embeddings
self.config = config
self.model_dim = config.d_model
self.shared = nn.Embedding(config.vocab_size, config.d_model)
encoder_config = copy.deepcopy(config)
encoder_config.is_decoder = False
self.encoder = FlashT5Stack(encoder_config, self.shared)
decoder_config = copy.deepcopy(config)
decoder_config.is_decoder = True
decoder_config.num_layers = config.num_decoder_layers
self.decoder = FlashT5Stack(decoder_config, self.shared)
self.lm_head = nn.Linear(config.d_model, config.vocab_size, bias=False)
self.loss_fct = FlashT5CrossEntropyLoss(z_loss_factor=config.z_loss,
label_smoothing=config.label_smoothing,
use_triton_crossentropy=config.use_triton_crossentropy)
# Initialize weights and apply final processing
self.post_init()
def prepare_inputs_for_generation(
self, input_ids, past_key_values=None, attention_mask=None, inputs_embeds=None, **kwargs
):
# do nothing
model_inputs = {"input_ids": input_ids, "attention_mask": attention_mask}
return model_inputs
def get_input_embeddings(self):
return self.shared
def set_input_embeddings(self, value):
self.shared = value
def generate(
self,
input_ids: Optional[torch.LongTensor] = None,
attention_mask: Optional[torch.FloatTensor] = None,
max_length = 32,
**kwargs,
) -> torch.LongTensor:
"""
input_ids: B x L_encoder, int64
attention_mask: B x L_encoder, int64
1 for tokens to attend to, 0 for tokens to ignore
Generation:
Starts with 0, ends with 1, padding is 0
# For 20 input/outputs, the diff between my implementation and HF is 9.8s vs 11.4s
"""
B, _ = input_ids.size()
labels = torch.zeros(B, 1, dtype=torch.long, device=input_ids.device)
encoder_outputs = None
for _ in range(max_length):
out = self.forward(
input_ids=input_ids,
attention_mask=attention_mask,
decoder_input_ids=labels,
encoder_outputs=encoder_outputs,
)
encoder_outputs = out.encoder_outputs
top_labels = out.logits[:, -1].argmax(-1).unsqueeze(-1)
labels = torch.cat([labels, top_labels], dim=-1)
if (labels == 1).sum(-1).clamp(min=0, max=1).sum().item() == B:
break
labels[:, -1] = 1
# Mask out the padding, i.e., all positions after the first 1 with 0
B, L = labels.size()
mask = torch.arange(L, device=labels.device).unsqueeze(0) <= (labels == 1).long().argmax(-1).unsqueeze(-1)
labels = labels.masked_fill(~mask, 0)
return labels
def forward(
self,
input_ids: Optional[torch.LongTensor] = None,
attention_mask: Optional[torch.FloatTensor] = None,
decoder_input_ids: Optional[torch.LongTensor] = None,
decoder_attention_mask: Optional[torch.BoolTensor] = None,
labels: Optional[torch.LongTensor] = None,
encoder_outputs = None,
) -> Seq2SeqLMOutput:
"""
input_ids: B x L_encoder, int64
attention_mask: B x L_encoder, int64
1 for tokens to attend to, 0 for tokens to ignore
labels: B x L_decoder, int64
"""
if encoder_outputs is None:
encoder_outputs = self.encoder(
input_ids=input_ids,
attention_mask=attention_mask,
)
hidden_states = encoder_outputs.hidden_states
if labels is not None and decoder_input_ids is None:
decoder_input_ids = self._shift_right(labels)
decoder_outputs = self.decoder(
input_ids=decoder_input_ids,
attention_mask=decoder_attention_mask,
encoder_hidden_states=hidden_states,
encoder_attention_mask=attention_mask,
)
sequence_output = decoder_outputs[0]
lm_logits = self.lm_head(sequence_output)
loss = None
if labels is not None:
loss, z_loss = self.loss_fct(lm_logits, labels)
loss += z_loss
return Seq2SeqLMOutput(
loss=loss,
logits=lm_logits,
encoder_outputs=encoder_outputs,
)
class FlashT5EncoderModel(FlashT5PreTrainedModel):
_tied_weights_keys = ["encoder.embed_tokens.weight"]
def __init__(self, config: FlashT5Config):
super().__init__(config)
self.shared = nn.Embedding(config.vocab_size, config.d_model)
encoder_config = copy.deepcopy(config)
encoder_config.use_cache = False
encoder_config.is_encoder_decoder = False
self.encoder = FlashT5Stack(encoder_config, self.shared)
# Initialize weights and apply final processing
self.post_init()
# Model parallel
self.model_parallel = False
self.device_map = None
def parallelize(self, device_map=None):
warnings.warn(
"`T5EncoderModel.parallelize` is deprecated and will be removed in v5 of Transformers, you should load"
" your model with `device_map='balanced'` in the call to `from_pretrained`. You can also provide your own"
" `device_map` but it needs to be a dictionary module_name to device, so for instance {'block.0': 0,"
" 'block.1': 1, ...}",
FutureWarning,
)
self.device_map = (
get_device_map(len(self.encoder.block), range(torch.cuda.device_count()))
if device_map is None
else device_map
)
assert_device_map(self.device_map, len(self.encoder.block))
self.encoder.parallelize(self.device_map)
self.model_parallel = True
def deparallelize(self):
warnings.warn(
"Like `parallelize`, `deparallelize` is deprecated and will be removed in v5 of Transformers.",
FutureWarning,
)
self.encoder.deparallelize()
self.encoder = self.encoder.to("cpu")
self.model_parallel = False
self.device_map = None
torch.cuda.empty_cache()
def get_input_embeddings(self):
return self.shared
def set_input_embeddings(self, new_embeddings):
self.shared = new_embeddings
self.encoder.set_input_embeddings(new_embeddings)
def get_encoder(self):
return self.encoder
def _prune_heads(self, heads_to_prune):
"""
Prunes heads of the model. heads_to_prune: dict of {layer_num: list of heads to prune in this layer} See base
class PreTrainedModel
"""
for layer, heads in heads_to_prune.items():
self.encoder.block[layer].layer[0].SelfAttention.prune_heads(heads)
def forward(
self,
input_ids: Optional[torch.LongTensor] = None,
attention_mask: Optional[torch.FloatTensor] = None,
head_mask: Optional[torch.FloatTensor] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
) -> Union[Tuple[torch.FloatTensor], BaseModelOutput]:
r"""
Returns:
Example:
```python
>>> from transformers import AutoTokenizer, T5EncoderModel
>>> tokenizer = AutoTokenizer.from_pretrained("t5-small")
>>> model = T5EncoderModel.from_pretrained("t5-small")
>>> input_ids = tokenizer(
... "Studies have been shown that owning a dog is good for you", return_tensors="pt"
... ).input_ids # Batch size 1
>>> outputs = model(input_ids=input_ids)
>>> last_hidden_states = outputs.last_hidden_state
```"""
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
encoder_outputs = self.encoder(
input_ids=input_ids,
attention_mask=attention_mask,
inputs_embeds=inputs_embeds,
head_mask=head_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
)
return encoder_outputs |