# coding=utf-8
# Copyright 2022 Microsoft Research and The HuggingFace Inc. team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
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"""PyTorch LayoutLMv3 model."""

import collections
import math

import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.utils.checkpoint
from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss

from transformers import apply_chunking_to_forward
from transformers.modeling_outputs import (
    BaseModelOutput,
    QuestionAnsweringModelOutput,
    SequenceClassifierOutput,
    TokenClassifierOutput,
)
from transformers.modeling_utils import PreTrainedModel
from transformers.utils import logging

from ...activations import ACT2FN
from ...utils import add_start_docstrings, add_start_docstrings_to_model_forward, replace_return_docstrings
from .configuration_layoutlmv3 import LayoutLMv3Config


logger = logging.get_logger(__name__)

_CONFIG_FOR_DOC = "LayoutLMv3Config"

LAYOUTLMV3_PRETRAINED_MODEL_ARCHIVE_LIST = [
    "microsoft/layoutlmv3-base",
    "microsoft/layoutlmv3-large",
    # See all LayoutLMv3 models at https://huggingface.co/models?filter=layoutlmv3
]

LAYOUTLMV3_START_DOCSTRING = r"""
    This model is a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) sub-class. Use
    it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and
    behavior.

    Parameters:
        config ([`LayoutLMv2Config`]): Model configuration class with all the parameters of the model.
            Initializing with a config file does not load the weights associated with the model, only the
            configuration. Check out the [`~PreTrainedModel.from_pretrained`] method to load the model weights.
"""

LAYOUTLMV3_INPUTS_DOCSTRING = r"""
    Args:
        input_ids (`torch.LongTensor` of shape `{0}`):
            Indices of input sequence tokens in the vocabulary.

            Indices can be obtained using [`LayoutLMv2Tokenizer`]. See [`PreTrainedTokenizer.encode`] and
            [`PreTrainedTokenizer.__call__`] for details.

            [What are input IDs?](../glossary#input-ids)

        bbox (`torch.LongTensor` of shape `({0}, 4)`, *optional*):
            Bounding boxes of each input sequence tokens. Selected in the range `[0,
            config.max_2d_position_embeddings-1]`. Each bounding box should be a normalized version in (x0, y0, x1, y1)
            format, where (x0, y0) corresponds to the position of the upper left corner in the bounding box, and (x1,
            y1) represents the position of the lower right corner.

        pixel_values (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`):
            Batch of document images.

        attention_mask (`torch.FloatTensor` of shape `{0}`, *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)
        token_type_ids (`torch.LongTensor` of shape `{0}`, *optional*):
            Segment token indices to indicate first and second portions of the inputs. Indices are selected in `[0,
            1]`:

            - 0 corresponds to a *sentence A* token,
            - 1 corresponds to a *sentence B* token.

            [What are token type IDs?](../glossary#token-type-ids)
        position_ids (`torch.LongTensor` of shape `{0}`, *optional*):
            Indices of positions of each input sequence tokens in the position embeddings. Selected in the range `[0,
            config.max_position_embeddings - 1]`.

            [What are position IDs?](../glossary#position-ids)
        head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*):
            Mask to nullify selected heads of the self-attention modules. Mask values selected in `[0, 1]`:

            - 1 indicates the head is **not masked**,
            - 0 indicates the head is **masked**.

        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.
"""


class LayoutLMv3PatchEmbeddings(nn.Module):
    """LayoutLMv3 image (patch) embeddings. This class also automatically interpolates the position embeddings for varying
    image sizes."""

    def __init__(self, config):
        super().__init__()

        image_size = (
            config.input_size
            if isinstance(config.input_size, collections.abc.Iterable)
            else (config.input_size, config.input_size)
        )
        patch_size = (
            config.patch_size
            if isinstance(config.patch_size, collections.abc.Iterable)
            else (config.patch_size, config.patch_size)
        )
        self.patch_shape = (image_size[0] // patch_size[0], image_size[1] // patch_size[1])
        self.proj = nn.Conv2d(config.num_channels, config.hidden_size, kernel_size=patch_size, stride=patch_size)

    def forward(self, pixel_values, position_embedding=None):
        embeddings = self.proj(pixel_values)

        if position_embedding is not None:
            # interpolate the position embedding to the corresponding size
            position_embedding = position_embedding.view(1, self.patch_shape[0], self.patch_shape[1], -1)
            position_embedding = position_embedding.permute(0, 3, 1, 2)
            patch_height, patch_width = embeddings.shape[2], embeddings.shape[3]
            position_embedding = F.interpolate(position_embedding, size=(patch_height, patch_width), mode="bicubic")
            embeddings = embeddings + position_embedding

        embeddings = embeddings.flatten(2).transpose(1, 2)
        return embeddings


class LayoutLMv3TextEmbeddings(nn.Module):
    """
    LayoutLMv3 text embeddings. Same as `RobertaEmbeddings` but with added spatial (layout) embeddings.
    """

    def __init__(self, config):
        super().__init__()
        self.word_embeddings = nn.Embedding(config.vocab_size, config.hidden_size, padding_idx=config.pad_token_id)
        self.token_type_embeddings = nn.Embedding(config.type_vocab_size, config.hidden_size)

        self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.dropout = nn.Dropout(config.hidden_dropout_prob)

        # position_ids (1, len position emb) is contiguous in memory and exported when serialized
        self.register_buffer("position_ids", torch.arange(config.max_position_embeddings).expand((1, -1)))

        self.padding_idx = config.pad_token_id
        self.position_embeddings = nn.Embedding(
            config.max_position_embeddings, config.hidden_size, padding_idx=self.padding_idx
        )

        self.x_position_embeddings = nn.Embedding(config.max_2d_position_embeddings, config.coordinate_size)
        self.y_position_embeddings = nn.Embedding(config.max_2d_position_embeddings, config.coordinate_size)
        self.h_position_embeddings = nn.Embedding(config.max_2d_position_embeddings, config.shape_size)
        self.w_position_embeddings = nn.Embedding(config.max_2d_position_embeddings, config.shape_size)

    def calculate_spatial_position_embeddings(self, bbox):
        try:
            left_position_embeddings = self.x_position_embeddings(bbox[:, :, 0])
            upper_position_embeddings = self.y_position_embeddings(bbox[:, :, 1])
            right_position_embeddings = self.x_position_embeddings(bbox[:, :, 2])
            lower_position_embeddings = self.y_position_embeddings(bbox[:, :, 3])
        except IndexError as e:
            raise IndexError("The `bbox` coordinate values should be within 0-1000 range.") from e

        h_position_embeddings = self.h_position_embeddings(torch.clip(bbox[:, :, 3] - bbox[:, :, 1], 0, 1023))
        w_position_embeddings = self.w_position_embeddings(torch.clip(bbox[:, :, 2] - bbox[:, :, 0], 0, 1023))

        # below is the difference between LayoutLMEmbeddingsV2 (torch.cat) and LayoutLMEmbeddingsV1 (add)
        spatial_position_embeddings = torch.cat(
            [
                left_position_embeddings,
                upper_position_embeddings,
                right_position_embeddings,
                lower_position_embeddings,
                h_position_embeddings,
                w_position_embeddings,
            ],
            dim=-1,
        )
        return spatial_position_embeddings

    def create_position_ids_from_input_ids(self, input_ids, padding_idx):
        """
        Replace non-padding symbols with their position numbers. Position numbers begin at padding_idx+1. Padding
        symbols are ignored. This is modified from fairseq's `utils.make_positions`.
        """
        # The series of casts and type-conversions here are carefully balanced to both work with ONNX export and XLA.
        mask = input_ids.ne(padding_idx).int()
        incremental_indices = (torch.cumsum(mask, dim=1).type_as(mask)) * mask
        return incremental_indices.long() + padding_idx

    def create_position_ids_from_inputs_embeds(self, inputs_embeds):
        """
        We are provided embeddings directly. We cannot infer which are padded so just generate sequential position ids.
        """
        input_shape = inputs_embeds.size()[:-1]
        sequence_length = input_shape[1]

        position_ids = torch.arange(
            self.padding_idx + 1, sequence_length + self.padding_idx + 1, dtype=torch.long, device=inputs_embeds.device
        )
        return position_ids.unsqueeze(0).expand(input_shape)

    def forward(
        self,
        input_ids=None,
        bbox=None,
        token_type_ids=None,
        position_ids=None,
        inputs_embeds=None,
    ):
        if position_ids is None:
            if input_ids is not None:
                # Create the position ids from the input token ids. Any padded tokens remain padded.
                position_ids = self.create_position_ids_from_input_ids(input_ids, self.padding_idx).to(
                    input_ids.device
                )
            else:
                position_ids = self.create_position_ids_from_inputs_embeds(inputs_embeds)

        if input_ids is not None:
            input_shape = input_ids.size()
        else:
            input_shape = inputs_embeds.size()[:-1]

        if token_type_ids is None:
            token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=self.position_ids.device)

        if inputs_embeds is None:
            inputs_embeds = self.word_embeddings(input_ids)
        token_type_embeddings = self.token_type_embeddings(token_type_ids)

        embeddings = inputs_embeds + token_type_embeddings
        position_embeddings = self.position_embeddings(position_ids)
        embeddings += position_embeddings

        spatial_position_embeddings = self.calculate_spatial_position_embeddings(bbox)

        embeddings = embeddings + spatial_position_embeddings

        embeddings = self.LayerNorm(embeddings)
        embeddings = self.dropout(embeddings)
        return embeddings


class LayoutLMv3PreTrainedModel(PreTrainedModel):
    """
    An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
    models.
    """

    config_class = LayoutLMv3Config
    base_model_prefix = "layoutlmv3"

    def _init_weights(self, module):
        """Initialize the weights"""
        if isinstance(module, (nn.Linear, nn.Conv2d)):
            # Slightly different from the TF version which uses truncated_normal for initialization
            # cf https://github.com/pytorch/pytorch/pull/5617
            module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
            if module.bias is not None:
                module.bias.data.zero_()
        elif isinstance(module, nn.Embedding):
            module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
            if module.padding_idx is not None:
                module.weight.data[module.padding_idx].zero_()
        elif isinstance(module, nn.LayerNorm):
            module.bias.data.zero_()
            module.weight.data.fill_(1.0)


class LayoutLMv3SelfAttention(nn.Module):
    def __init__(self, config):
        super().__init__()
        if config.hidden_size % config.num_attention_heads != 0 and not hasattr(config, "embedding_size"):
            raise ValueError(
                f"The hidden size ({config.hidden_size}) is not a multiple of the number of attention "
                f"heads ({config.num_attention_heads})"
            )

        self.num_attention_heads = config.num_attention_heads
        self.attention_head_size = int(config.hidden_size / config.num_attention_heads)
        self.all_head_size = self.num_attention_heads * self.attention_head_size

        self.query = nn.Linear(config.hidden_size, self.all_head_size)
        self.key = nn.Linear(config.hidden_size, self.all_head_size)
        self.value = nn.Linear(config.hidden_size, self.all_head_size)

        self.dropout = nn.Dropout(config.attention_probs_dropout_prob)
        self.has_relative_attention_bias = config.has_relative_attention_bias
        self.has_spatial_attention_bias = config.has_spatial_attention_bias

    def transpose_for_scores(self, x):
        new_x_shape = x.size()[:-1] + (self.num_attention_heads, self.attention_head_size)
        x = x.view(*new_x_shape)
        return x.permute(0, 2, 1, 3)

    def cogview_attention(self, attention_scores, alpha=32):
        """
        https://arxiv.org/abs/2105.13290 Section 2.4 Stabilization of training: Precision Bottleneck Relaxation
        (PB-Relax). A replacement of the original nn.Softmax(dim=-1)(attention_scores). Seems the new attention_probs
        will result in a slower speed and a little bias. Can use torch.allclose(standard_attention_probs,
        cogview_attention_probs, atol=1e-08) for comparison. The smaller atol (e.g., 1e-08), the better.
        """
        scaled_attention_scores = attention_scores / alpha
        max_value = scaled_attention_scores.amax(dim=(-1)).unsqueeze(-1)
        new_attention_scores = (scaled_attention_scores - max_value) * alpha
        return nn.Softmax(dim=-1)(new_attention_scores)

    def forward(
        self,
        hidden_states,
        attention_mask=None,
        head_mask=None,
        output_attentions=False,
        rel_pos=None,
        rel_2d_pos=None,
    ):
        mixed_query_layer = self.query(hidden_states)

        key_layer = self.transpose_for_scores(self.key(hidden_states))
        value_layer = self.transpose_for_scores(self.value(hidden_states))
        query_layer = self.transpose_for_scores(mixed_query_layer)

        # Take the dot product between "query" and "key" to get the raw attention scores.
        # The attention scores QT K/√d could be significantly larger than input elements, and result in overflow.
        # Changing the computational order into QT(K/√d) alleviates the problem. (https://arxiv.org/pdf/2105.13290.pdf)
        attention_scores = torch.matmul(query_layer / math.sqrt(self.attention_head_size), key_layer.transpose(-1, -2))

        if self.has_relative_attention_bias and self.has_spatial_attention_bias:
            attention_scores += (rel_pos + rel_2d_pos) / math.sqrt(self.attention_head_size)
        elif self.has_relative_attention_bias:
            attention_scores += rel_pos / math.sqrt(self.attention_head_size)

        if attention_mask is not None:
            # Apply the attention mask is (precomputed for all layers in RobertaModel forward() function)
            attention_scores = attention_scores + attention_mask

        # Normalize the attention scores to probabilities.
        # Use the trick of the CogView paper to stablize training
        attention_probs = self.cogview_attention(attention_scores)

        # This is actually dropping out entire tokens to attend to, which might
        # seem a bit unusual, but is taken from the original Transformer paper.
        attention_probs = self.dropout(attention_probs)

        # Mask heads if we want to
        if head_mask is not None:
            attention_probs = attention_probs * head_mask

        context_layer = torch.matmul(attention_probs, value_layer)

        context_layer = context_layer.permute(0, 2, 1, 3).contiguous()
        new_context_layer_shape = context_layer.size()[:-2] + (self.all_head_size,)
        context_layer = context_layer.view(*new_context_layer_shape)

        outputs = (context_layer, attention_probs) if output_attentions else (context_layer,)

        return outputs


# Copied from transformers.models.roberta.modeling_roberta.RobertaSelfOutput
class LayoutLMv3SelfOutput(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.dense = nn.Linear(config.hidden_size, config.hidden_size)
        self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.dropout = nn.Dropout(config.hidden_dropout_prob)

    def forward(self, hidden_states: torch.Tensor, input_tensor: torch.Tensor) -> torch.Tensor:
        hidden_states = self.dense(hidden_states)
        hidden_states = self.dropout(hidden_states)
        hidden_states = self.LayerNorm(hidden_states + input_tensor)
        return hidden_states


# Copied from transformers.models.layoutlmv2.modeling_layoutlmv2.LayoutLMv2Attention with LayoutLMv2->LayoutLMv3
class LayoutLMv3Attention(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.self = LayoutLMv3SelfAttention(config)
        self.output = LayoutLMv3SelfOutput(config)

    def forward(
        self,
        hidden_states,
        attention_mask=None,
        head_mask=None,
        output_attentions=False,
        rel_pos=None,
        rel_2d_pos=None,
    ):
        self_outputs = self.self(
            hidden_states,
            attention_mask,
            head_mask,
            output_attentions,
            rel_pos=rel_pos,
            rel_2d_pos=rel_2d_pos,
        )
        attention_output = self.output(self_outputs[0], hidden_states)
        outputs = (attention_output,) + self_outputs[1:]  # add attentions if we output them
        return outputs


# Copied from transformers.models.layoutlmv2.modeling_layoutlmv2.LayoutLMv2Layer with LayoutLMv2->LayoutLMv3
class LayoutLMv3Layer(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.chunk_size_feed_forward = config.chunk_size_feed_forward
        self.seq_len_dim = 1
        self.attention = LayoutLMv3Attention(config)
        self.intermediate = LayoutLMv3Intermediate(config)
        self.output = LayoutLMv3Output(config)

    def forward(
        self,
        hidden_states,
        attention_mask=None,
        head_mask=None,
        output_attentions=False,
        rel_pos=None,
        rel_2d_pos=None,
    ):
        self_attention_outputs = self.attention(
            hidden_states,
            attention_mask,
            head_mask,
            output_attentions=output_attentions,
            rel_pos=rel_pos,
            rel_2d_pos=rel_2d_pos,
        )
        attention_output = self_attention_outputs[0]

        outputs = self_attention_outputs[1:]  # add self attentions if we output attention weights

        layer_output = apply_chunking_to_forward(
            self.feed_forward_chunk, self.chunk_size_feed_forward, self.seq_len_dim, attention_output
        )
        outputs = (layer_output,) + outputs

        return outputs

    def feed_forward_chunk(self, attention_output):
        intermediate_output = self.intermediate(attention_output)
        layer_output = self.output(intermediate_output, attention_output)
        return layer_output


class LayoutLMv3Encoder(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.config = config
        self.layer = nn.ModuleList([LayoutLMv3Layer(config) for _ in range(config.num_hidden_layers)])
        self.gradient_checkpointing = False

        self.has_relative_attention_bias = config.has_relative_attention_bias
        self.has_spatial_attention_bias = config.has_spatial_attention_bias

        if self.has_relative_attention_bias:
            self.rel_pos_bins = config.rel_pos_bins
            self.max_rel_pos = config.max_rel_pos
            self.rel_pos_onehot_size = config.rel_pos_bins
            self.rel_pos_bias = nn.Linear(self.rel_pos_onehot_size, config.num_attention_heads, bias=False)

        if self.has_spatial_attention_bias:
            self.max_rel_2d_pos = config.max_rel_2d_pos
            self.rel_2d_pos_bins = config.rel_2d_pos_bins
            self.rel_2d_pos_onehot_size = config.rel_2d_pos_bins
            self.rel_pos_x_bias = nn.Linear(self.rel_2d_pos_onehot_size, config.num_attention_heads, bias=False)
            self.rel_pos_y_bias = nn.Linear(self.rel_2d_pos_onehot_size, config.num_attention_heads, bias=False)

    def relative_position_bucket(self, relative_position, bidirectional=True, num_buckets=32, max_distance=128):
        ret = 0
        if bidirectional:
            num_buckets //= 2
            ret += (relative_position > 0).long() * num_buckets
            n = torch.abs(relative_position)
        else:
            n = torch.max(-relative_position, torch.zeros_like(relative_position))
        # now n is in the range [0, inf)

        # half of the buckets are for exact increments in positions
        max_exact = num_buckets // 2
        is_small = n < max_exact

        # The other half of the buckets are for logarithmically bigger bins in positions up to max_distance
        val_if_large = max_exact + (
            torch.log(n.float() / max_exact) / math.log(max_distance / max_exact) * (num_buckets - max_exact)
        ).to(torch.long)
        val_if_large = torch.min(val_if_large, torch.full_like(val_if_large, num_buckets - 1))

        ret += torch.where(is_small, n, val_if_large)
        return ret

    def _cal_1d_pos_emb(self, hidden_states, position_ids):
        rel_pos_mat = position_ids.unsqueeze(-2) - position_ids.unsqueeze(-1)

        rel_pos = self.relative_position_bucket(
            rel_pos_mat,
            num_buckets=self.rel_pos_bins,
            max_distance=self.max_rel_pos,
        )
        rel_pos = F.one_hot(rel_pos, num_classes=self.rel_pos_onehot_size).type_as(hidden_states)
        rel_pos = self.rel_pos_bias(rel_pos).permute(0, 3, 1, 2)
        rel_pos = rel_pos.contiguous()
        return rel_pos

    def _cal_2d_pos_emb(self, hidden_states, bbox):
        position_coord_x = bbox[:, :, 0]
        position_coord_y = bbox[:, :, 3]
        rel_pos_x_2d_mat = position_coord_x.unsqueeze(-2) - position_coord_x.unsqueeze(-1)
        rel_pos_y_2d_mat = position_coord_y.unsqueeze(-2) - position_coord_y.unsqueeze(-1)
        rel_pos_x = self.relative_position_bucket(
            rel_pos_x_2d_mat,
            num_buckets=self.rel_2d_pos_bins,
            max_distance=self.max_rel_2d_pos,
        )
        rel_pos_y = self.relative_position_bucket(
            rel_pos_y_2d_mat,
            num_buckets=self.rel_2d_pos_bins,
            max_distance=self.max_rel_2d_pos,
        )
        rel_pos_x = F.one_hot(rel_pos_x, num_classes=self.rel_2d_pos_onehot_size).type_as(hidden_states)
        rel_pos_y = F.one_hot(rel_pos_y, num_classes=self.rel_2d_pos_onehot_size).type_as(hidden_states)
        rel_pos_x = self.rel_pos_x_bias(rel_pos_x).permute(0, 3, 1, 2)
        rel_pos_y = self.rel_pos_y_bias(rel_pos_y).permute(0, 3, 1, 2)
        rel_pos_x = rel_pos_x.contiguous()
        rel_pos_y = rel_pos_y.contiguous()
        rel_2d_pos = rel_pos_x + rel_pos_y
        return rel_2d_pos

    def forward(
        self,
        hidden_states,
        bbox=None,
        attention_mask=None,
        head_mask=None,
        output_attentions=False,
        output_hidden_states=False,
        return_dict=True,
        position_ids=None,
        patch_height=None,
        patch_width=None,
    ):
        all_hidden_states = () if output_hidden_states else None
        all_self_attentions = () if output_attentions else None

        rel_pos = self._cal_1d_pos_emb(hidden_states, position_ids) if self.has_relative_attention_bias else None
        rel_2d_pos = self._cal_2d_pos_emb(hidden_states, bbox) if self.has_spatial_attention_bias else None

        for i, layer_module in enumerate(self.layer):
            if output_hidden_states:
                all_hidden_states = all_hidden_states + (hidden_states,)

            layer_head_mask = head_mask[i] if head_mask is not None else None

            if self.gradient_checkpointing and self.training:

                def create_custom_forward(module):
                    def custom_forward(*inputs):
                        return module(*inputs)
                        # return module(*inputs, past_key_value, output_attentions, rel_pos, rel_2d_pos)
                        # The above line will cause error:
                        # RuntimeError: Trying to backward through the graph a second time
                        # (or directly access saved tensors after they have already been freed).

                    return custom_forward

                layer_outputs = torch.utils.checkpoint.checkpoint(
                    create_custom_forward(layer_module),
                    hidden_states,
                    attention_mask,
                    layer_head_mask,
                    output_attentions,
                    rel_pos,
                    rel_2d_pos,
                )
            else:
                layer_outputs = layer_module(
                    hidden_states,
                    attention_mask,
                    layer_head_mask,
                    output_attentions,
                    rel_pos=rel_pos,
                    rel_2d_pos=rel_2d_pos,
                )

            hidden_states = layer_outputs[0]
            if output_attentions:
                all_self_attentions = all_self_attentions + (layer_outputs[1],)

        if output_hidden_states:
            all_hidden_states = all_hidden_states + (hidden_states,)

        if not return_dict:
            return tuple(
                v
                for v in [
                    hidden_states,
                    all_hidden_states,
                    all_self_attentions,
                ]
                if v is not None
            )
        return BaseModelOutput(
            last_hidden_state=hidden_states,
            hidden_states=all_hidden_states,
            attentions=all_self_attentions,
        )


# Copied from transformers.models.roberta.modeling_roberta.RobertaIntermediate
class LayoutLMv3Intermediate(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.dense = nn.Linear(config.hidden_size, config.intermediate_size)
        if isinstance(config.hidden_act, str):
            self.intermediate_act_fn = ACT2FN[config.hidden_act]
        else:
            self.intermediate_act_fn = config.hidden_act

    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
        hidden_states = self.dense(hidden_states)
        hidden_states = self.intermediate_act_fn(hidden_states)
        return hidden_states


# Copied from transformers.models.roberta.modeling_roberta.RobertaOutput
class LayoutLMv3Output(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.dense = nn.Linear(config.intermediate_size, config.hidden_size)
        self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.dropout = nn.Dropout(config.hidden_dropout_prob)

    def forward(self, hidden_states: torch.Tensor, input_tensor: torch.Tensor) -> torch.Tensor:
        hidden_states = self.dense(hidden_states)
        hidden_states = self.dropout(hidden_states)
        hidden_states = self.LayerNorm(hidden_states + input_tensor)
        return hidden_states


@add_start_docstrings(
    "The bare LayoutLMv3 Model transformer outputting raw hidden-states without any specific head on top.",
    LAYOUTLMV3_START_DOCSTRING,
)
class LayoutLMv3Model(LayoutLMv3PreTrainedModel):
    _keys_to_ignore_on_load_missing = [r"position_ids"]

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

        if config.text_embed:
            self.embeddings = LayoutLMv3TextEmbeddings(config)

        if config.visual_embed:
            # use the default pre-training parameters for fine-tuning (e.g., input_size)
            # when the input_size is larger in fine-tuning, we will interpolate the position embeddings in forward
            self.patch_embed = LayoutLMv3PatchEmbeddings(config)

            size = int(config.input_size / config.patch_size)
            self.cls_token = nn.Parameter(torch.zeros(1, 1, config.hidden_size))
            self.pos_embed = nn.Parameter(torch.zeros(1, size * size + 1, config.hidden_size))
            self.pos_drop = nn.Dropout(p=0.0)

            self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
            self.dropout = nn.Dropout(config.hidden_dropout_prob)

            if self.config.has_relative_attention_bias or self.config.has_spatial_attention_bias:
                self.init_visual_bbox(image_size=(size, size))

            self.norm = nn.LayerNorm(config.hidden_size, eps=1e-6)

        self.encoder = LayoutLMv3Encoder(config)

        self.init_weights()

    def get_input_embeddings(self):
        return self.embeddings.word_embeddings

    def set_input_embeddings(self, value):
        self.embeddings.word_embeddings = value

    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.layer[layer].attention.prune_heads(heads)

    def init_visual_bbox(self, image_size=(14, 14), max_len=1000):
        """
        Create the bounding boxes for the visual (patch) tokens.
        """
        visual_bbox_x = torch.div(
            torch.arange(0, max_len * (image_size[1] + 1), max_len), image_size[1], rounding_mode="trunc"
        )
        visual_bbox_y = torch.div(
            torch.arange(0, max_len * (image_size[0] + 1), max_len), image_size[0], rounding_mode="trunc"
        )
        visual_bbox = torch.stack(
            [
                visual_bbox_x[:-1].repeat(image_size[0], 1),
                visual_bbox_y[:-1].repeat(image_size[1], 1).transpose(0, 1),
                visual_bbox_x[1:].repeat(image_size[0], 1),
                visual_bbox_y[1:].repeat(image_size[1], 1).transpose(0, 1),
            ],
            dim=-1,
        ).view(-1, 4)

        cls_token_box = torch.tensor([[0 + 1, 0 + 1, max_len - 1, max_len - 1]])
        self.visual_bbox = torch.cat([cls_token_box, visual_bbox], dim=0)

    def calculate_visual_bbox(self, device, dtype, batch_size):
        visual_bbox = self.visual_bbox.repeat(batch_size, 1, 1)
        visual_bbox = visual_bbox.to(device).type(dtype)
        return visual_bbox

    def forward_image(self, pixel_values):
        embeddings = self.patch_embed(pixel_values)

        # add [CLS] token
        batch_size, seq_len, _ = embeddings.size()
        cls_tokens = self.cls_token.expand(batch_size, -1, -1)
        embeddings = torch.cat((cls_tokens, embeddings), dim=1)

        # add position embeddings
        if self.pos_embed is not None:
            embeddings = embeddings + self.pos_embed

        embeddings = self.pos_drop(embeddings)
        embeddings = self.norm(embeddings)

        return embeddings

    @add_start_docstrings_to_model_forward(LAYOUTLMV3_INPUTS_DOCSTRING.format("(batch_size, sequence_length)"))
    @replace_return_docstrings(output_type=BaseModelOutput, config_class=_CONFIG_FOR_DOC)
    def forward(
        self,
        input_ids=None,
        bbox=None,
        attention_mask=None,
        token_type_ids=None,
        position_ids=None,
        head_mask=None,
        inputs_embeds=None,
        pixel_values=None,
        output_attentions=None,
        output_hidden_states=None,
        return_dict=None,
    ):
        r"""
        Returns:

        Examples:

        ```python
        >>> from transformers import AutoProcessor, AutoModel
        >>> from datasets import load_dataset

        >>> processor = AutoProcessor.from_pretrained("microsoft/layoutlmv3-base", apply_ocr=False)
        >>> model = AutoModel.from_pretrained("microsoft/layoutlmv3-base")

        >>> dataset = load_dataset("nielsr/funsd-layoutlmv3", split="train")
        >>> example = dataset[0]
        >>> image = example["image"]
        >>> words = example["tokens"]
        >>> boxes = example["bboxes"]

        >>> encoding = processor(image, words, boxes=boxes, return_tensors="pt")

        >>> outputs = model(**encoding)
        >>> last_hidden_states = outputs.last_hidden_state
        ```"""
        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

        if input_ids is not None:
            input_shape = input_ids.size()
            batch_size, seq_length = input_shape
            device = input_ids.device
        elif inputs_embeds is not None:
            input_shape = inputs_embeds.size()[:-1]
            batch_size, seq_length = input_shape
            device = inputs_embeds.device
        elif pixel_values is not None:
            batch_size = len(pixel_values)
            device = pixel_values.device
        else:
            raise ValueError("You have to specify either input_ids or inputs_embeds or pixel_values")

        if input_ids is not None or inputs_embeds is not None:
            if attention_mask is None:
                attention_mask = torch.ones(((batch_size, seq_length)), device=device)
            if token_type_ids is None:
                token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=device)
            if bbox is None:
                bbox = torch.zeros(tuple(list(input_shape) + [4]), dtype=torch.long, device=device)

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

        final_bbox = final_position_ids = None
        patch_height = patch_width = None
        if pixel_values is not None:
            patch_height, patch_width = int(pixel_values.shape[2] / self.config.patch_size), int(
                pixel_values.shape[3] / self.config.patch_size
            )
            visual_embeddings = self.forward_image(pixel_values)
            visual_attention_mask = torch.ones(
                (batch_size, visual_embeddings.shape[1]), dtype=torch.long, device=device
            )
            if attention_mask is not None:
                attention_mask = torch.cat([attention_mask, visual_attention_mask], dim=1)
            else:
                attention_mask = visual_attention_mask

            if self.config.has_relative_attention_bias or self.config.has_spatial_attention_bias:
                if self.config.has_spatial_attention_bias:
                    visual_bbox = self.calculate_visual_bbox(device, dtype=torch.long, batch_size=batch_size)
                    if bbox is not None:
                        final_bbox = torch.cat([bbox, visual_bbox], dim=1)
                    else:
                        final_bbox = visual_bbox

                visual_position_ids = torch.arange(
                    0, visual_embeddings.shape[1], dtype=torch.long, device=device
                ).repeat(batch_size, 1)
                if input_ids is not None or inputs_embeds is not None:
                    position_ids = torch.arange(0, input_shape[1], device=device).unsqueeze(0)
                    position_ids = position_ids.expand(input_shape)
                    final_position_ids = torch.cat([position_ids, visual_position_ids], dim=1)
                else:
                    final_position_ids = visual_position_ids

            if input_ids is not None or inputs_embeds is not None:
                embedding_output = torch.cat([embedding_output, visual_embeddings], dim=1)
            else:
                embedding_output = visual_embeddings

            embedding_output = self.LayerNorm(embedding_output)
            embedding_output = self.dropout(embedding_output)
        elif self.config.has_relative_attention_bias or self.config.has_spatial_attention_bias:
            if self.config.has_spatial_attention_bias:
                final_bbox = bbox
            if self.config.has_relative_attention_bias:
                position_ids = self.embeddings.position_ids[:, : input_shape[1]]
                position_ids = position_ids.expand_as(input_ids)
                final_position_ids = position_ids

        extended_attention_mask: torch.Tensor = self.get_extended_attention_mask(attention_mask, None, device)

        # Prepare head mask if needed
        # 1.0 in head_mask indicate we keep the head
        # attention_probs has shape bsz x n_heads x N x N
        # input head_mask has shape [num_heads] or [num_hidden_layers x num_heads]
        # and head_mask is converted to shape [num_hidden_layers x batch x num_heads x seq_length x seq_length]
        head_mask = self.get_head_mask(head_mask, self.config.num_hidden_layers)

        encoder_outputs = self.encoder(
            embedding_output,
            bbox=final_bbox,
            position_ids=final_position_ids,
            attention_mask=extended_attention_mask,
            head_mask=head_mask,
            output_attentions=output_attentions,
            output_hidden_states=output_hidden_states,
            return_dict=return_dict,
            patch_height=patch_height,
            patch_width=patch_width,
        )

        sequence_output = encoder_outputs[0]

        if not return_dict:
            return (sequence_output,) + encoder_outputs[1:]

        return BaseModelOutput(
            last_hidden_state=sequence_output,
            hidden_states=encoder_outputs.hidden_states,
            attentions=encoder_outputs.attentions,
        )


class LayoutLMv3ClassificationHead(nn.Module):
    """
    Head for sentence-level classification tasks. Reference: RobertaClassificationHead
    """

    def __init__(self, config, pool_feature=False):
        super().__init__()
        self.pool_feature = pool_feature
        if pool_feature:
            self.dense = nn.Linear(config.hidden_size * 3, config.hidden_size)
        else:
            self.dense = nn.Linear(config.hidden_size, config.hidden_size)
        classifier_dropout = (
            config.classifier_dropout if config.classifier_dropout is not None else config.hidden_dropout_prob
        )
        self.dropout = nn.Dropout(classifier_dropout)
        self.out_proj = nn.Linear(config.hidden_size, config.num_labels)

    def forward(self, x):
        x = self.dropout(x)
        x = self.dense(x)
        x = torch.tanh(x)
        x = self.dropout(x)
        x = self.out_proj(x)
        return x


@add_start_docstrings(
    """
    LayoutLMv3 Model with a token classification head on top (a linear layer on top of the final hidden states) e.g.
    for sequence labeling (information extraction) tasks such as [FUNSD](https://guillaumejaume.github.io/FUNSD/),
    [SROIE](https://rrc.cvc.uab.es/?ch=13), [CORD](https://github.com/clovaai/cord) and
    [Kleister-NDA](https://github.com/applicaai/kleister-nda).
    """,
    LAYOUTLMV3_START_DOCSTRING,
)
class LayoutLMv3ForTokenClassification(LayoutLMv3PreTrainedModel):
    _keys_to_ignore_on_load_unexpected = [r"pooler"]
    _keys_to_ignore_on_load_missing = [r"position_ids"]

    def __init__(self, config):
        super().__init__(config)
        self.num_labels = config.num_labels

        self.layoutlmv3 = LayoutLMv3Model(config)
        self.dropout = nn.Dropout(config.hidden_dropout_prob)
        if config.num_labels < 10:
            self.classifier = nn.Linear(config.hidden_size, config.num_labels)
        else:
            self.classifier = LayoutLMv3ClassificationHead(config, pool_feature=False)

        self.init_weights()

    @add_start_docstrings_to_model_forward(LAYOUTLMV3_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
    @replace_return_docstrings(output_type=TokenClassifierOutput, config_class=_CONFIG_FOR_DOC)
    def forward(
        self,
        input_ids=None,
        bbox=None,
        attention_mask=None,
        token_type_ids=None,
        position_ids=None,
        head_mask=None,
        inputs_embeds=None,
        labels=None,
        output_attentions=None,
        output_hidden_states=None,
        return_dict=None,
        pixel_values=None,
    ):
        r"""
        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
            Labels for computing the token classification loss. Indices should be in `[0, ..., config.num_labels - 1]`.

        Returns:

        Examples:

        ```python
        >>> from transformers import AutoProcessor, AutoModelForTokenClassification
        >>> from datasets import load_dataset

        >>> processor = AutoProcessor.from_pretrained("microsoft/layoutlmv3-base", apply_ocr=False)
        >>> model = AutoModelForTokenClassification.from_pretrained("microsoft/layoutlmv3-base", num_labels=7)

        >>> dataset = load_dataset("nielsr/funsd-layoutlmv3", split="train")
        >>> example = dataset[0]
        >>> image = example["image"]
        >>> words = example["tokens"]
        >>> boxes = example["bboxes"]
        >>> word_labels = example["ner_tags"]

        >>> encoding = processor(image, words, boxes=boxes, word_labels=word_labels, return_tensors="pt")

        >>> outputs = model(**encoding)
        >>> loss = outputs.loss
        >>> logits = outputs.logits
        ```"""
        return_dict = return_dict if return_dict is not None else self.config.use_return_dict

        outputs = self.layoutlmv3(
            input_ids,
            bbox=bbox,
            attention_mask=attention_mask,
            token_type_ids=token_type_ids,
            position_ids=position_ids,
            head_mask=head_mask,
            inputs_embeds=inputs_embeds,
            output_attentions=output_attentions,
            output_hidden_states=output_hidden_states,
            return_dict=return_dict,
            pixel_values=pixel_values,
        )
        if input_ids is not None:
            input_shape = input_ids.size()
        else:
            input_shape = inputs_embeds.size()[:-1]

        seq_length = input_shape[1]
        # only take the text part of the output representations
        sequence_output = outputs[0][:, :seq_length]
        sequence_output = self.dropout(sequence_output)
        logits = self.classifier(sequence_output)

        loss = None
        if labels is not None:
            loss_fct = CrossEntropyLoss()
            loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))

        if not return_dict:
            output = (logits,) + outputs[1:]
            return ((loss,) + output) if loss is not None else output

        return TokenClassifierOutput(
            loss=loss,
            logits=logits,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
        )


@add_start_docstrings(
    """
    LayoutLMv3 Model with a span classification head on top for extractive question-answering tasks such as
    [DocVQA](https://rrc.cvc.uab.es/?ch=17) (a linear layer on top of the text part of the hidden-states output to
    compute `span start logits` and `span end logits`).
    """,
    LAYOUTLMV3_START_DOCSTRING,
)
class LayoutLMv3ForQuestionAnswering(LayoutLMv3PreTrainedModel):
    _keys_to_ignore_on_load_unexpected = [r"pooler"]
    _keys_to_ignore_on_load_missing = [r"position_ids"]

    def __init__(self, config):
        super().__init__(config)
        self.num_labels = config.num_labels

        self.layoutlmv3 = LayoutLMv3Model(config)
        self.qa_outputs = LayoutLMv3ClassificationHead(config, pool_feature=False)

        self.init_weights()

    @add_start_docstrings_to_model_forward(LAYOUTLMV3_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
    @replace_return_docstrings(output_type=QuestionAnsweringModelOutput, config_class=_CONFIG_FOR_DOC)
    def forward(
        self,
        input_ids=None,
        attention_mask=None,
        token_type_ids=None,
        position_ids=None,
        head_mask=None,
        inputs_embeds=None,
        start_positions=None,
        end_positions=None,
        output_attentions=None,
        output_hidden_states=None,
        return_dict=None,
        bbox=None,
        pixel_values=None,
    ):
        r"""
        start_positions (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
            Labels for position (index) of the start of the labelled span for computing the token classification loss.
            Positions are clamped to the length of the sequence (`sequence_length`). Position outside of the sequence
            are not taken into account for computing the loss.
        end_positions (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
            Labels for position (index) of the end of the labelled span for computing the token classification loss.
            Positions are clamped to the length of the sequence (`sequence_length`). Position outside of the sequence
            are not taken into account for computing the loss.

        Returns:

        Examples:

        ```python
        >>> from transformers import AutoProcessor, AutoModelForQuestionAnswering
        >>> from datasets import load_dataset
        >>> import torch

        >>> processor = AutoProcessor.from_pretrained("microsoft/layoutlmv3-base", apply_ocr=False)
        >>> model = AutoModelForQuestionAnswering.from_pretrained("microsoft/layoutlmv3-base")

        >>> dataset = load_dataset("nielsr/funsd-layoutlmv3", split="train")
        >>> example = dataset[0]
        >>> image = example["image"]
        >>> question = "what's his name?"
        >>> words = example["tokens"]
        >>> boxes = example["bboxes"]

        >>> encoding = processor(image, question, words, boxes=boxes, return_tensors="pt")
        >>> start_positions = torch.tensor([1])
        >>> end_positions = torch.tensor([3])

        >>> outputs = model(**encoding, start_positions=start_positions, end_positions=end_positions)
        >>> loss = outputs.loss
        >>> start_scores = outputs.start_logits
        >>> end_scores = outputs.end_logits
        ```"""

        return_dict = return_dict if return_dict is not None else self.config.use_return_dict

        outputs = self.layoutlmv3(
            input_ids,
            attention_mask=attention_mask,
            token_type_ids=token_type_ids,
            position_ids=position_ids,
            head_mask=head_mask,
            inputs_embeds=inputs_embeds,
            output_attentions=output_attentions,
            output_hidden_states=output_hidden_states,
            return_dict=return_dict,
            bbox=bbox,
            pixel_values=pixel_values,
        )

        sequence_output = outputs[0]

        logits = self.qa_outputs(sequence_output)
        start_logits, end_logits = logits.split(1, dim=-1)
        start_logits = start_logits.squeeze(-1).contiguous()
        end_logits = end_logits.squeeze(-1).contiguous()

        total_loss = None
        if start_positions is not None and end_positions is not None:
            # If we are on multi-GPU, split add a dimension
            if len(start_positions.size()) > 1:
                start_positions = start_positions.squeeze(-1)
            if len(end_positions.size()) > 1:
                end_positions = end_positions.squeeze(-1)
            # sometimes the start/end positions are outside our model inputs, we ignore these terms
            ignored_index = start_logits.size(1)
            start_positions = start_positions.clamp(0, ignored_index)
            end_positions = end_positions.clamp(0, ignored_index)

            loss_fct = CrossEntropyLoss(ignore_index=ignored_index)
            start_loss = loss_fct(start_logits, start_positions)
            end_loss = loss_fct(end_logits, end_positions)
            total_loss = (start_loss + end_loss) / 2

        if not return_dict:
            output = (start_logits, end_logits) + outputs[1:]
            return ((total_loss,) + output) if total_loss is not None else output

        return QuestionAnsweringModelOutput(
            loss=total_loss,
            start_logits=start_logits,
            end_logits=end_logits,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
        )


@add_start_docstrings(
    """
    LayoutLMv3 Model with a sequence classification head on top (a linear layer on top of the final hidden state of the
    [CLS] token) e.g. for document image classification tasks such as the
    [RVL-CDIP](https://www.cs.cmu.edu/~aharley/rvl-cdip/) dataset.
    """,
    LAYOUTLMV3_START_DOCSTRING,
)
class LayoutLMv3ForSequenceClassification(LayoutLMv3PreTrainedModel):
    _keys_to_ignore_on_load_missing = [r"position_ids"]

    def __init__(self, config):
        super().__init__(config)
        self.num_labels = config.num_labels
        self.config = config
        self.layoutlmv3 = LayoutLMv3Model(config)
        self.classifier = LayoutLMv3ClassificationHead(config, pool_feature=False)

        self.init_weights()

    @add_start_docstrings_to_model_forward(LAYOUTLMV3_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
    @replace_return_docstrings(output_type=SequenceClassifierOutput, config_class=_CONFIG_FOR_DOC)
    def forward(
        self,
        input_ids=None,
        attention_mask=None,
        token_type_ids=None,
        position_ids=None,
        head_mask=None,
        inputs_embeds=None,
        labels=None,
        output_attentions=None,
        output_hidden_states=None,
        return_dict=None,
        bbox=None,
        pixel_values=None,
    ):
        """
        Returns:

        Examples:

        ```python
        >>> from transformers import AutoProcessor, AutoModelForSequenceClassification
        >>> from datasets import load_dataset
        >>> import torch

        >>> processor = AutoProcessor.from_pretrained("microsoft/layoutlmv3-base", apply_ocr=False)
        >>> model = AutoModelForSequenceClassification.from_pretrained("microsoft/layoutlmv3-base")

        >>> dataset = load_dataset("nielsr/funsd-layoutlmv3", split="train")
        >>> example = dataset[0]
        >>> image = example["image"]
        >>> words = example["tokens"]
        >>> boxes = example["bboxes"]

        >>> encoding = processor(image, words, boxes=boxes, return_tensors="pt")
        >>> sequence_label = torch.tensor([1])

        >>> outputs = model(**encoding, labels=sequence_label)
        >>> loss = outputs.loss
        >>> logits = outputs.logits
        ```"""
        return_dict = return_dict if return_dict is not None else self.config.use_return_dict

        outputs = self.layoutlmv3(
            input_ids,
            attention_mask=attention_mask,
            token_type_ids=token_type_ids,
            position_ids=position_ids,
            head_mask=head_mask,
            inputs_embeds=inputs_embeds,
            output_attentions=output_attentions,
            output_hidden_states=output_hidden_states,
            return_dict=return_dict,
            bbox=bbox,
            pixel_values=pixel_values,
        )

        sequence_output = outputs[0][:, 0, :]
        logits = self.classifier(sequence_output)

        loss = None
        if labels is not None:
            if self.config.problem_type is None:
                if self.num_labels == 1:
                    self.config.problem_type = "regression"
                elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int):
                    self.config.problem_type = "single_label_classification"
                else:
                    self.config.problem_type = "multi_label_classification"

            if self.config.problem_type == "regression":
                loss_fct = MSELoss()
                if self.num_labels == 1:
                    loss = loss_fct(logits.squeeze(), labels.squeeze())
                else:
                    loss = loss_fct(logits, labels)
            elif self.config.problem_type == "single_label_classification":
                loss_fct = CrossEntropyLoss()
                loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))
            elif self.config.problem_type == "multi_label_classification":
                loss_fct = BCEWithLogitsLoss()
                loss = loss_fct(logits, labels)

        if not return_dict:
            output = (logits,) + outputs[1:]
            return ((loss,) + output) if loss is not None else output

        return SequenceClassifierOutput(
            loss=loss,
            logits=logits,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
        )
