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788 lines
34 KiB
788 lines
34 KiB
# Copyright 2021 The Fairseq Authors and The HuggingFace Inc. team. All rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""PyTorch TrOCR decoder model (based on RoBERTa)."""
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import math
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import torch
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from torch import nn
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from torch.nn import CrossEntropyLoss
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from ...activations import ACT2FN
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from ...cache_utils import Cache, DynamicCache, EncoderDecoderCache
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from ...generation import GenerationMixin
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from ...modeling_attn_mask_utils import (
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_prepare_4d_attention_mask,
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_prepare_4d_causal_attention_mask,
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)
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from ...modeling_layers import GradientCheckpointingLayer
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from ...modeling_outputs import BaseModelOutputWithPastAndCrossAttentions, CausalLMOutputWithCrossAttentions
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from ...modeling_utils import PreTrainedModel
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from ...utils import auto_docstring, logging
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from .configuration_trocr import TrOCRConfig
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logger = logging.get_logger(__name__)
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# Copied from transformers.models.bart.modeling_bart.BartLearnedPositionalEmbedding with Bart->TrOCR
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class TrOCRLearnedPositionalEmbedding(nn.Embedding):
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"""
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This module learns positional embeddings up to a fixed maximum size.
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"""
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def __init__(self, num_embeddings: int, embedding_dim: int):
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# TrOCR is set up so that if padding_idx is specified then offset the embedding ids by 2
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# and adjust num_embeddings appropriately. Other models don't have this hack
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self.offset = 2
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super().__init__(num_embeddings + self.offset, embedding_dim)
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def forward(
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self, input_ids: torch.Tensor, past_key_values_length: int = 0, position_ids: torch.Tensor | None = None
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):
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"""`input_ids' shape is expected to be [bsz x seqlen]."""
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if position_ids is None:
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bsz, seq_len = input_ids.shape[:2]
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position_ids = torch.arange(
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past_key_values_length, past_key_values_length + seq_len, dtype=torch.long, device=self.weight.device
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).expand(bsz, -1)
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else:
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position_ids = position_ids.unsqueeze(0)
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return super().forward(position_ids + self.offset)
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# Copied from transformers.models.bart.modeling_bart.BartScaledWordEmbedding with Bart->TrOCR
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class TrOCRScaledWordEmbedding(nn.Embedding):
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"""
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This module overrides nn.Embeddings' forward by multiplying with embeddings scale.
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"""
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def __init__(self, num_embeddings: int, embedding_dim: int, padding_idx: int, embed_scale: float | None = 1.0):
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super().__init__(num_embeddings, embedding_dim, padding_idx)
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self.embed_scale = embed_scale
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def forward(self, input_ids: torch.Tensor):
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return super().forward(input_ids) * self.embed_scale
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class TrOCRSinusoidalPositionalEmbedding(nn.Module):
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"""This module produces sinusoidal positional embeddings of any length."""
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def __init__(self, num_positions: int, embedding_dim: int, padding_idx: int | None = None):
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super().__init__()
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self.offset = 2
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self.embedding_dim = embedding_dim
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self.padding_idx = padding_idx
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self.weights = self.get_embedding(num_positions, embedding_dim, padding_idx)
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@staticmethod
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def get_embedding(num_embeddings: int, embedding_dim: int, padding_idx: int | None = None):
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"""
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Build sinusoidal embeddings. This matches the implementation in tensor2tensor, but differs slightly from the
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description in Section 3.5 of "Attention Is All You Need".
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"""
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half_dim = embedding_dim // 2
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emb = math.log(10000) / (half_dim - 1)
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emb = torch.exp(torch.arange(half_dim, dtype=torch.int64).float() * -emb)
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emb = torch.arange(num_embeddings, dtype=torch.int64).float().unsqueeze(1) * emb.unsqueeze(0)
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emb = torch.cat([torch.sin(emb), torch.cos(emb)], dim=1).view(num_embeddings, -1)
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if embedding_dim % 2 == 1:
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# zero pad
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emb = torch.cat([emb, torch.zeros(num_embeddings, 1)], dim=1)
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if padding_idx is not None:
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emb[padding_idx, :] = 0
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return emb.to(torch.get_default_dtype())
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@torch.no_grad()
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def forward(self, input_ids: torch.Tensor, past_key_values_length: int = 0):
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bsz, seq_len = input_ids.size()
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# Create the position ids from the input token ids. Any padded tokens remain padded.
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position_ids = self.create_position_ids_from_input_ids(input_ids, self.padding_idx, past_key_values_length).to(
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input_ids.device
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)
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# expand embeddings if needed
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max_pos = self.padding_idx + 1 + seq_len
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if self.weights is None or max_pos > self.weights.size(0):
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# recompute/expand embeddings if needed
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self.weights = self.get_embedding(max_pos, self.embedding_dim, self.padding_idx)
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x = self.weights.index_select(0, position_ids.view(-1)).view(bsz, seq_len, -1).detach()
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return x
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def create_position_ids_from_input_ids(
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self, input_ids: torch.Tensor, padding_idx: int, past_key_values_length: int | None = 0
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):
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"""
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Replace non-padding symbols with their position numbers. Position numbers begin at padding_idx+1. Padding
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symbols are ignored. This is modified from fairseq's `utils.make_positions`.
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"""
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# The series of casts and type-conversions here are carefully balanced to both work with ONNX export and XLA.
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mask = input_ids.ne(padding_idx).int()
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incremental_indices = (torch.cumsum(mask, dim=1).type_as(mask) + past_key_values_length) * mask
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return incremental_indices.long() + padding_idx
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class TrOCRAttention(nn.Module):
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"""Multi-headed attention from 'Attention Is All You Need' paper."""
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def __init__(
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self,
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config,
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embed_dim: int,
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num_heads: int,
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kdim: int | None = None,
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vdim: int | None = None,
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dropout: float | None = 0.0,
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is_decoder: bool | None = False,
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bias: bool | None = True,
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is_cross_attention: bool | None = False,
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layer_idx: bool | None = None,
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):
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super().__init__()
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self.embed_dim = embed_dim
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self.kdim = kdim if kdim is not None else embed_dim
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self.vdim = vdim if vdim is not None else embed_dim
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self.num_heads = num_heads
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self.dropout = dropout
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self.head_dim = embed_dim // num_heads
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if not (self.head_dim * num_heads == self.embed_dim):
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raise ValueError(
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f"embed_dim must be divisible by num_heads (got `embed_dim`: {self.embed_dim} and `num_heads`:"
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f" {num_heads})."
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)
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self.scaling = self.head_dim**-0.5
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self.is_decoder = is_decoder
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self.layer_idx = layer_idx
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self.k_proj = nn.Linear(self.kdim, embed_dim, bias=bias)
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self.v_proj = nn.Linear(self.vdim, embed_dim, bias=bias)
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self.q_proj = nn.Linear(embed_dim, embed_dim, bias=bias)
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self.out_proj = nn.Linear(embed_dim, embed_dim, bias=bias)
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def forward(
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self,
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hidden_states: torch.Tensor,
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key_value_states: torch.Tensor | None = None,
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past_key_values: Cache | None = None,
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attention_mask: torch.Tensor | None = None,
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output_attentions: bool | None = False,
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cache_position: torch.Tensor | None = None,
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) -> tuple[torch.Tensor, torch.Tensor | None, tuple[torch.Tensor] | None]:
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"""Input shape: Batch x Time x Channel"""
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# if key_value_states are provided this layer is used as a cross-attention layer
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# for the decoder
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is_cross_attention = key_value_states is not None
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bsz, tgt_len, embed_dim = hidden_states.size()
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# get query proj
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query_states = self.q_proj(hidden_states) * self.scaling
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is_updated = False
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if past_key_values is not None:
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if isinstance(past_key_values, EncoderDecoderCache):
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is_updated = past_key_values.is_updated.get(self.layer_idx)
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if is_cross_attention:
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# after the first generated id, we can subsequently re-use all key/value_states from cache
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curr_past_key_values = past_key_values.cross_attention_cache
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else:
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curr_past_key_values = past_key_values.self_attention_cache
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else:
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curr_past_key_values = past_key_values
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current_states = key_value_states if is_cross_attention else hidden_states
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if is_cross_attention and past_key_values is not None and is_updated:
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# reuse k,v, cross_attentions
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key_states = curr_past_key_values.layers[self.layer_idx].keys
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value_states = curr_past_key_values.layers[self.layer_idx].values
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else:
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key_states = self.k_proj(current_states)
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value_states = self.v_proj(current_states)
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key_states = key_states.view(bsz, -1, self.num_heads, self.head_dim).transpose(1, 2)
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value_states = value_states.view(bsz, -1, self.num_heads, self.head_dim).transpose(1, 2)
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if past_key_values is not None:
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# save all key/value_states to cache to be re-used for fast auto-regressive generation
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cache_position = cache_position if not is_cross_attention else None
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key_states, value_states = curr_past_key_values.update(
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key_states, value_states, self.layer_idx, {"cache_position": cache_position}
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)
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# set flag that curr layer for cross-attn is already updated so we can re-use in subsequent calls
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if is_cross_attention and isinstance(past_key_values, EncoderDecoderCache):
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past_key_values.is_updated[self.layer_idx] = True
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proj_shape = (bsz * self.num_heads, -1, self.head_dim)
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query_states = query_states.view(bsz, tgt_len, self.num_heads, self.head_dim).transpose(1, 2)
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query_states = query_states.reshape(*proj_shape)
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key_states = key_states.reshape(*proj_shape)
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value_states = value_states.reshape(*proj_shape)
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src_len = key_states.size(1)
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attn_weights = torch.bmm(query_states, key_states.transpose(1, 2))
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if attn_weights.size() != (bsz * self.num_heads, tgt_len, src_len):
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raise ValueError(
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f"Attention weights should be of size {(bsz * self.num_heads, tgt_len, src_len)}, but is"
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f" {attn_weights.size()}"
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)
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if attention_mask is not None:
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if attention_mask.size() != (bsz, 1, tgt_len, src_len):
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raise ValueError(
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f"Attention mask should be of size {(bsz, 1, tgt_len, src_len)}, but is {attention_mask.size()}"
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)
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attn_weights = attn_weights.view(bsz, self.num_heads, tgt_len, src_len) + attention_mask
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attn_weights = attn_weights.view(bsz * self.num_heads, tgt_len, src_len)
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attn_weights = nn.functional.softmax(attn_weights, dim=-1)
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if output_attentions:
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# this operation is a bit awkward, but it's required to
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# make sure that attn_weights keeps its gradient.
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# In order to do so, attn_weights have to be reshaped
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# twice and have to be reused in the following
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attn_weights_reshaped = attn_weights.view(bsz, self.num_heads, tgt_len, src_len)
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attn_weights = attn_weights_reshaped.view(bsz * self.num_heads, tgt_len, src_len)
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else:
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attn_weights_reshaped = None
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attn_probs = nn.functional.dropout(attn_weights, p=self.dropout, training=self.training)
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attn_output = torch.bmm(attn_probs, value_states)
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if attn_output.size() != (bsz * self.num_heads, tgt_len, self.head_dim):
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raise ValueError(
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f"`attn_output` should be of size {(bsz, self.num_heads, tgt_len, self.head_dim)}, but is"
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f" {attn_output.size()}"
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)
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attn_output = attn_output.view(bsz, self.num_heads, tgt_len, self.head_dim)
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attn_output = attn_output.transpose(1, 2)
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attn_output = attn_output.reshape(bsz, tgt_len, embed_dim)
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attn_output = self.out_proj(attn_output)
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return attn_output, attn_weights_reshaped
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class TrOCRDecoderLayer(GradientCheckpointingLayer):
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def __init__(self, config: TrOCRConfig, layer_idx=None):
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super().__init__()
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self.embed_dim = config.hidden_size
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self.self_attn = TrOCRAttention(
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config,
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embed_dim=self.embed_dim,
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num_heads=config.decoder_attention_heads,
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dropout=config.attention_dropout,
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is_decoder=True,
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layer_idx=layer_idx,
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)
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self.dropout = config.dropout
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self.activation_fn = ACT2FN[config.activation_function]
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self.activation_dropout = config.activation_dropout
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self.self_attn_layer_norm = nn.LayerNorm(self.embed_dim)
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if config.is_decoder:
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self.encoder_attn = TrOCRAttention(
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config,
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embed_dim=self.embed_dim,
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num_heads=config.decoder_attention_heads,
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kdim=config.cross_attention_hidden_size,
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vdim=config.cross_attention_hidden_size,
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dropout=config.attention_dropout,
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is_decoder=True,
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is_cross_attention=True,
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layer_idx=layer_idx,
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)
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self.encoder_attn_layer_norm = nn.LayerNorm(self.embed_dim)
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self.fc1 = nn.Linear(self.embed_dim, config.decoder_ffn_dim)
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self.fc2 = nn.Linear(config.decoder_ffn_dim, self.embed_dim)
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self.final_layer_norm = nn.LayerNorm(self.embed_dim)
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def forward(
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self,
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hidden_states: torch.Tensor,
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attention_mask: torch.Tensor | None = None,
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encoder_hidden_states: torch.Tensor | None = None,
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encoder_attention_mask: torch.Tensor | None = None,
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past_key_values: Cache | None = None,
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output_attentions: bool | None = False,
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use_cache: bool | None = True,
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cache_position: torch.Tensor | None = None,
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):
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"""
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Args:
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hidden_states (`torch.FloatTensor`): input to the layer of shape `(batch, seq_len, embed_dim)`
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attention_mask (`torch.FloatTensor`): attention mask of size
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`(batch, 1, tgt_len, src_len)` where padding elements are indicated by very large negative values.
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encoder_hidden_states (`torch.FloatTensor`):
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cross attention input to the layer of shape `(batch, seq_len, embed_dim)`
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encoder_attention_mask (`torch.FloatTensor`): encoder attention mask of size
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`(batch, 1, tgt_len, src_len)` where padding elements are indicated by very large negative values.
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past_key_values (`Cache`): cached past key and value projection states
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output_attentions (`bool`, *optional*):
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Whether or not to return the attentions tensors of all attention layers. See `attentions` under
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returned tensors for more detail.
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"""
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residual = hidden_states
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# Self Attention
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hidden_states, self_attn_weights = self.self_attn(
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hidden_states=hidden_states,
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past_key_values=past_key_values,
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attention_mask=attention_mask,
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output_attentions=output_attentions,
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cache_position=cache_position,
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)
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hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training)
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hidden_states = residual + hidden_states
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hidden_states = self.self_attn_layer_norm(hidden_states)
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# Cross-Attention Block
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cross_attn_weights = None
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if encoder_hidden_states is not None:
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residual = hidden_states
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hidden_states, cross_attn_weights = self.encoder_attn(
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hidden_states=hidden_states,
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key_value_states=encoder_hidden_states,
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attention_mask=encoder_attention_mask,
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past_key_values=past_key_values,
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output_attentions=output_attentions,
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cache_position=cache_position,
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)
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hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training)
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hidden_states = residual + hidden_states
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hidden_states = self.encoder_attn_layer_norm(hidden_states)
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# Fully Connected
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residual = hidden_states
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hidden_states = self.activation_fn(self.fc1(hidden_states))
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hidden_states = nn.functional.dropout(hidden_states, p=self.activation_dropout, training=self.training)
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hidden_states = self.fc2(hidden_states)
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hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training)
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hidden_states = residual + hidden_states
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hidden_states = self.final_layer_norm(hidden_states)
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outputs = (hidden_states,)
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if output_attentions:
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outputs += (self_attn_weights, cross_attn_weights)
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return outputs
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@auto_docstring
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class TrOCRPreTrainedModel(PreTrainedModel):
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config: TrOCRConfig
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base_model_prefix = "model"
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supports_gradient_checkpointing = True
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_no_split_modules = ["TrOCRDecoderLayer"]
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class TrOCRDecoder(TrOCRPreTrainedModel):
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"""
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Transformer decoder consisting of *config.decoder_layers* layers. Each layer is a [`TrOCRDecoderLayer`]
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Args:
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config: TrOCRConfig
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"""
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def __init__(self, config: TrOCRConfig):
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super().__init__(config)
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self.dropout = config.dropout
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self.layerdrop = config.decoder_layerdrop
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self.padding_idx = config.pad_token_id
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embed_scale = math.sqrt(config.hidden_size) if config.scale_embedding else 1.0
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self.embed_tokens = TrOCRScaledWordEmbedding(
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config.vocab_size, config.hidden_size, self.padding_idx, embed_scale=embed_scale
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)
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if config.use_learned_position_embeddings:
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self.embed_positions = TrOCRLearnedPositionalEmbedding(config.max_position_embeddings, config.hidden_size)
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else:
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self.embed_positions = TrOCRSinusoidalPositionalEmbedding(
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config.max_position_embeddings + self.padding_idx + 1,
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config.hidden_size,
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self.padding_idx,
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)
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if config.layernorm_embedding:
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|
self.layernorm_embedding = nn.LayerNorm(config.hidden_size)
|
|
else:
|
|
self.layernorm_embedding = None
|
|
|
|
self.layers = nn.ModuleList([TrOCRDecoderLayer(config, layer_idx=i) for i in range(config.decoder_layers)])
|
|
|
|
self.gradient_checkpointing = False
|
|
# Initialize weights and apply final processing
|
|
self.post_init()
|
|
|
|
def forward(
|
|
self,
|
|
input_ids=None,
|
|
attention_mask=None,
|
|
encoder_hidden_states=None,
|
|
encoder_attention_mask=None,
|
|
past_key_values=None,
|
|
inputs_embeds=None,
|
|
use_cache=None,
|
|
output_attentions=None,
|
|
output_hidden_states=None,
|
|
return_dict=None,
|
|
cache_position=None,
|
|
**kwargs,
|
|
):
|
|
r"""
|
|
Args:
|
|
input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
|
|
Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you
|
|
provide it.
|
|
|
|
Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
|
|
[`PreTrainedTokenizer.__call__`] for details.
|
|
|
|
[What are input IDs?](../glossary#input-ids)
|
|
attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*):
|
|
Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`:
|
|
|
|
- 1 for tokens that are **not masked**,
|
|
- 0 for tokens that are **masked**.
|
|
|
|
[What are attention masks?](../glossary#attention-mask)
|
|
encoder_hidden_states (`torch.FloatTensor` of shape `(batch_size, encoder_sequence_length, hidden_size)`, *optional*):
|
|
Sequence of hidden-states at the output of the last layer of the encoder. Used in the cross-attention
|
|
of the decoder.
|
|
encoder_attention_mask (`torch.LongTensor` of shape `(batch_size, encoder_sequence_length)`, *optional*):
|
|
Mask to avoid performing cross-attention on padding tokens indices of encoder input_ids. Mask values
|
|
selected in `[0, 1]`:
|
|
|
|
- 1 for tokens that are **not masked**,
|
|
- 0 for tokens that are **masked**.
|
|
|
|
[What are attention masks?](../glossary#attention-mask)
|
|
past_key_values (`Cache`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`):
|
|
It is a [`~cache_utils.Cache`] instance. For more details, see our [kv cache guide](https://huggingface.co/docs/transformers/en/kv_cache).
|
|
|
|
Contains pre-computed hidden-states (key and values in the self-attention blocks and in the
|
|
cross-attention blocks) that can be used (see `past_key_values` input) to speed up sequential decoding.
|
|
|
|
If `past_key_values` are used, the user can optionally input only the last `decoder_input_ids` (those
|
|
that don't have their past key value states given to this model) of shape `(batch_size, 1)` instead of
|
|
all `decoder_input_ids` of shape `(batch_size, sequence_length)`.
|
|
inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*):
|
|
Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation.
|
|
This is useful if you want more control over how to convert `input_ids` indices into associated vectors
|
|
than the model's internal embedding lookup matrix.
|
|
output_attentions (`bool`, *optional*):
|
|
Whether or not to return the attentions tensors of all attention layers. See `attentions` under
|
|
returned tensors for more detail.
|
|
output_hidden_states (`bool`, *optional*):
|
|
Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors
|
|
for more detail.
|
|
return_dict (`bool`, *optional*):
|
|
Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
|
|
"""
|
|
output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
|
|
output_hidden_states = (
|
|
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
|
|
)
|
|
use_cache = use_cache if use_cache is not None else self.config.use_cache
|
|
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
|
|
|
|
# retrieve input_ids and inputs_embeds
|
|
if input_ids is not None and inputs_embeds is not None:
|
|
raise ValueError("You cannot specify both decoder_input_ids and decoder_inputs_embeds at the same time")
|
|
elif input_ids is not None:
|
|
input = input_ids
|
|
input_ids = input_ids.view(-1, input.shape[-1])
|
|
elif inputs_embeds is not None:
|
|
input_shape = inputs_embeds.size()[:-1]
|
|
input = inputs_embeds[:, :, -1]
|
|
else:
|
|
raise ValueError("You have to specify either decoder_input_ids or decoder_inputs_embeds")
|
|
|
|
if self.gradient_checkpointing and self.training:
|
|
if use_cache:
|
|
logger.warning_once(
|
|
"`use_cache = True` is incompatible with gradient checkpointing. Setting `use_cache = False`..."
|
|
)
|
|
use_cache = False
|
|
|
|
if use_cache and past_key_values is None:
|
|
past_key_values = (
|
|
EncoderDecoderCache(DynamicCache(config=self.config), DynamicCache(config=self.config))
|
|
if encoder_hidden_states is not None or self.config.is_encoder_decoder
|
|
else DynamicCache(config=self.config)
|
|
)
|
|
|
|
past_key_values_length = past_key_values.get_seq_length() if past_key_values is not None else 0
|
|
|
|
if inputs_embeds is None:
|
|
inputs_embeds = self.embed_tokens(input_ids)
|
|
|
|
if self.config.use_learned_position_embeddings:
|
|
embed_pos = self.embed_positions(input, past_key_values_length=past_key_values_length)
|
|
else:
|
|
embed_pos = self.embed_positions(input_ids, past_key_values_length=past_key_values_length)
|
|
|
|
hidden_states = inputs_embeds + embed_pos
|
|
|
|
if self.layernorm_embedding is not None:
|
|
hidden_states = self.layernorm_embedding(hidden_states)
|
|
|
|
hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training)
|
|
|
|
input_shape = input.shape
|
|
|
|
attention_mask = _prepare_4d_causal_attention_mask(
|
|
attention_mask, input_shape, inputs_embeds, past_key_values_length
|
|
)
|
|
|
|
# expand encoder attention mask
|
|
if encoder_hidden_states is not None and encoder_attention_mask is not None:
|
|
# [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len]
|
|
encoder_attention_mask = _prepare_4d_attention_mask(
|
|
encoder_attention_mask, inputs_embeds.dtype, tgt_len=input_shape[-1]
|
|
)
|
|
|
|
# decoder layers
|
|
all_hidden_states = () if output_hidden_states else None
|
|
all_self_attns = () if output_attentions else None
|
|
all_cross_attentions = () if (output_attentions and encoder_hidden_states is not None) else None
|
|
|
|
for idx, decoder_layer in enumerate(self.layers):
|
|
# add LayerDrop (see https://huggingface.co/papers/1909.11556 for description)
|
|
if output_hidden_states:
|
|
all_hidden_states += (hidden_states,)
|
|
if self.training:
|
|
dropout_probability = torch.rand([])
|
|
if dropout_probability < self.layerdrop:
|
|
continue
|
|
|
|
layer_outputs = decoder_layer(
|
|
hidden_states,
|
|
attention_mask,
|
|
encoder_hidden_states, # as a positional argument for gradient checkpointing
|
|
encoder_attention_mask=encoder_attention_mask,
|
|
past_key_values=past_key_values,
|
|
output_attentions=output_attentions,
|
|
use_cache=use_cache,
|
|
cache_position=cache_position,
|
|
)
|
|
hidden_states = layer_outputs[0]
|
|
|
|
if output_attentions:
|
|
all_self_attns += (layer_outputs[1],)
|
|
|
|
if encoder_hidden_states is not None:
|
|
all_cross_attentions += (layer_outputs[2],)
|
|
|
|
# add hidden states from the last decoder layer
|
|
if output_hidden_states:
|
|
all_hidden_states += (hidden_states,)
|
|
|
|
if not return_dict:
|
|
return tuple(
|
|
v
|
|
for v in [hidden_states, past_key_values, all_hidden_states, all_self_attns, all_cross_attentions]
|
|
if v is not None
|
|
)
|
|
return BaseModelOutputWithPastAndCrossAttentions(
|
|
last_hidden_state=hidden_states,
|
|
past_key_values=past_key_values,
|
|
hidden_states=all_hidden_states,
|
|
attentions=all_self_attns,
|
|
cross_attentions=all_cross_attentions,
|
|
)
|
|
|
|
|
|
@auto_docstring(
|
|
custom_intro="""
|
|
The TrOCR Model with a language modeling head. Can be used for summarization.
|
|
This wrapper class is a helper class to correctly load pretrained checkpoints when the causal language model is
|
|
used in combination with the [`EncoderDecoderModel`] framework.
|
|
"""
|
|
)
|
|
class TrOCRDecoderWrapper(TrOCRPreTrainedModel):
|
|
def __init__(self, config):
|
|
super().__init__(config)
|
|
self.decoder = TrOCRDecoder(config)
|
|
self.post_init()
|
|
|
|
def forward(self, *args, **kwargs):
|
|
return self.decoder(*args, **kwargs)
|
|
|
|
|
|
@auto_docstring(
|
|
custom_intro="""
|
|
The TrOCR Decoder with a language modeling head. Can be used as the decoder part of [`EncoderDecoderModel`] and
|
|
"""
|
|
)
|
|
class TrOCRForCausalLM(TrOCRPreTrainedModel, GenerationMixin):
|
|
_tied_weights_keys = {"output_projection.weight": "model.decoder.embed_tokens.weight"}
|
|
|
|
def __init__(self, config):
|
|
config.is_decoder = True
|
|
config.is_encoder_decoder = False
|
|
super().__init__(config)
|
|
self.model = TrOCRDecoderWrapper(config)
|
|
|
|
self.output_projection = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
|
|
|
|
# Initialize weights and apply final processing
|
|
self.post_init()
|
|
|
|
def get_input_embeddings(self):
|
|
return self.model.decoder.embed_tokens
|
|
|
|
def set_input_embeddings(self, value):
|
|
self.model.decoder.embed_tokens = value
|
|
|
|
def get_output_embeddings(self):
|
|
return self.output_projection
|
|
|
|
def set_output_embeddings(self, new_embeddings):
|
|
self.output_projection = new_embeddings
|
|
|
|
@auto_docstring
|
|
def forward(
|
|
self,
|
|
input_ids: torch.LongTensor | None = None,
|
|
attention_mask: torch.Tensor | None = None,
|
|
encoder_hidden_states: torch.FloatTensor | None = None,
|
|
encoder_attention_mask: torch.LongTensor | None = None,
|
|
past_key_values: Cache | None = None,
|
|
inputs_embeds: torch.FloatTensor | None = None,
|
|
labels: torch.LongTensor | None = None,
|
|
use_cache: bool | None = None,
|
|
output_attentions: bool | None = None,
|
|
output_hidden_states: bool | None = None,
|
|
return_dict: bool | None = None,
|
|
cache_position: torch.Tensor | None = None,
|
|
**kwargs,
|
|
) -> tuple | CausalLMOutputWithCrossAttentions:
|
|
r"""
|
|
labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
|
|
Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
|
|
config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
|
|
(masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.
|
|
|
|
Example:
|
|
|
|
```python
|
|
>>> from transformers import (
|
|
... TrOCRConfig,
|
|
... TrOCRProcessor,
|
|
... TrOCRForCausalLM,
|
|
... ViTConfig,
|
|
... ViTModel,
|
|
... VisionEncoderDecoderModel,
|
|
... )
|
|
>>> import httpx
|
|
>>> from io import BytesIO
|
|
>>> from PIL import Image
|
|
|
|
>>> # TrOCR is a decoder model and should be used within a VisionEncoderDecoderModel
|
|
>>> # init vision2text model with random weights
|
|
>>> encoder = ViTModel(ViTConfig())
|
|
>>> decoder = TrOCRForCausalLM(TrOCRConfig())
|
|
>>> model = VisionEncoderDecoderModel(encoder=encoder, decoder=decoder)
|
|
|
|
>>> # If you want to start from the pretrained model, load the checkpoint with `VisionEncoderDecoderModel`
|
|
>>> processor = TrOCRProcessor.from_pretrained("microsoft/trocr-base-handwritten")
|
|
>>> model = VisionEncoderDecoderModel.from_pretrained("microsoft/trocr-base-handwritten")
|
|
|
|
>>> # load image from the IAM dataset
|
|
>>> url = "https://fki.tic.heia-fr.ch/static/img/a01-122-02.jpg"
|
|
>>> with httpx.stream("GET", url) as response:
|
|
... image = Image.open(BytesIO(response.read())).convert("RGB")
|
|
>>> pixel_values = processor(image, return_tensors="pt").pixel_values
|
|
>>> text = "industry, ' Mr. Brown commented icily. ' Let us have a"
|
|
|
|
>>> # training
|
|
>>> model.config.decoder_start_token_id = processor.tokenizer.eos_token_id
|
|
>>> model.config.pad_token_id = processor.tokenizer.pad_token_id
|
|
>>> model.config.vocab_size = model.config.decoder.vocab_size
|
|
|
|
>>> labels = processor.tokenizer(text, return_tensors="pt").input_ids
|
|
>>> outputs = model(pixel_values, labels=labels)
|
|
>>> loss = outputs.loss
|
|
>>> round(loss.item(), 2)
|
|
5.30
|
|
|
|
>>> # inference
|
|
>>> generated_ids = model.generate(pixel_values)
|
|
>>> generated_text = processor.batch_decode(generated_ids, skip_special_tokens=True)[0]
|
|
>>> generated_text
|
|
'industry, " Mr. Brown commented icily. " Let us have a'
|
|
```"""
|
|
|
|
output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
|
|
output_hidden_states = (
|
|
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
|
|
)
|
|
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
|
|
|
|
# decoder outputs consists of (dec_features, layer_state, dec_hidden, dec_attn)
|
|
outputs = self.model.decoder(
|
|
input_ids=input_ids,
|
|
attention_mask=attention_mask,
|
|
encoder_hidden_states=encoder_hidden_states,
|
|
encoder_attention_mask=encoder_attention_mask,
|
|
past_key_values=past_key_values,
|
|
inputs_embeds=inputs_embeds,
|
|
use_cache=use_cache,
|
|
output_attentions=output_attentions,
|
|
output_hidden_states=output_hidden_states,
|
|
return_dict=return_dict,
|
|
cache_position=cache_position,
|
|
)
|
|
|
|
logits = self.output_projection(outputs[0])
|
|
|
|
loss = None
|
|
if labels is not None:
|
|
loss_fct = CrossEntropyLoss()
|
|
loss = loss_fct(logits.view(-1, self.config.vocab_size), labels.view(-1))
|
|
|
|
if not return_dict:
|
|
output = (logits,) + outputs[1:]
|
|
return (loss,) + output if loss is not None else output
|
|
|
|
return CausalLMOutputWithCrossAttentions(
|
|
loss=loss,
|
|
logits=logits,
|
|
past_key_values=outputs.past_key_values,
|
|
hidden_states=outputs.hidden_states,
|
|
attentions=outputs.attentions,
|
|
cross_attentions=outputs.cross_attentions,
|
|
)
|
|
|
|
|
|
__all__ = ["TrOCRForCausalLM", "TrOCRPreTrainedModel"]
|