image-match/python/py/Lib/site-packages/transformers/models/yolos/modeling_yolos.py

# Copyright 2022 School of EIC, Huazhong University of Science & Technology and The HuggingFace Inc. team. All rights reserved.
#
# 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
# limitations under the License.
"""PyTorch YOLOS model."""

import collections.abc
from collections.abc import Callable
from dataclasses import dataclass

import torch
from torch import nn

from ...activations import ACT2FN
from ...modeling_layers import GradientCheckpointingLayer
from ...modeling_outputs import BaseModelOutput, BaseModelOutputWithPooling
from ...modeling_utils import ALL_ATTENTION_FUNCTIONS, PreTrainedModel
from ...processing_utils import Unpack
from ...utils import ModelOutput, TransformersKwargs, auto_docstring, logging
from ...utils.generic import can_return_tuple, merge_with_config_defaults
from ...utils.output_capturing import capture_outputs
from .configuration_yolos import YolosConfig


logger = logging.get_logger(__name__)


@dataclass
@auto_docstring(
    custom_intro="""
    Output type of [`YolosForObjectDetection`].
    """
)
class YolosObjectDetectionOutput(ModelOutput):
    r"""
    loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` are provided)):
        Total loss as a linear combination of a negative log-likehood (cross-entropy) for class prediction and a
        bounding box loss. The latter is defined as a linear combination of the L1 loss and the generalized
        scale-invariant IoU loss.
    loss_dict (`Dict`, *optional*):
        A dictionary containing the individual losses. Useful for logging.
    logits (`torch.FloatTensor` of shape `(batch_size, num_queries, num_classes + 1)`):
        Classification logits (including no-object) for all queries.
    pred_boxes (`torch.FloatTensor` of shape `(batch_size, num_queries, 4)`):
        Normalized boxes coordinates for all queries, represented as (center_x, center_y, width, height). These
        values are normalized in [0, 1], relative to the size of each individual image in the batch (disregarding
        possible padding). You can use [`~YolosImageProcessor.post_process`] to retrieve the unnormalized bounding
        boxes.
    auxiliary_outputs (`list[Dict]`, *optional*):
        Optional, only returned when auxiliary losses are activated (i.e. `config.auxiliary_loss` is set to `True`)
        and labels are provided. It is a list of dictionaries containing the two above keys (`logits` and
        `pred_boxes`) for each decoder layer.
    last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*):
        Sequence of hidden-states at the output of the last layer of the decoder of the model.
    """

    loss: torch.FloatTensor | None = None
    loss_dict: dict | None = None
    logits: torch.FloatTensor | None = None
    pred_boxes: torch.FloatTensor | None = None
    auxiliary_outputs: list[dict] | None = None
    last_hidden_state: torch.FloatTensor | None = None
    hidden_states: tuple[torch.FloatTensor] | None = None
    attentions: tuple[torch.FloatTensor] | None = None


class YolosEmbeddings(nn.Module):
    """
    Construct the CLS token, detection tokens, position and patch embeddings.

    """

    def __init__(self, config: YolosConfig) -> None:
        super().__init__()

        self.cls_token = nn.Parameter(torch.zeros(1, 1, config.hidden_size))
        self.detection_tokens = nn.Parameter(torch.zeros(1, config.num_detection_tokens, config.hidden_size))
        self.patch_embeddings = YolosPatchEmbeddings(config)
        num_patches = self.patch_embeddings.num_patches
        self.position_embeddings = nn.Parameter(
            torch.zeros(1, num_patches + config.num_detection_tokens + 1, config.hidden_size)
        )

        self.dropout = nn.Dropout(config.hidden_dropout_prob)
        self.interpolation = InterpolateInitialPositionEmbeddings(config)
        self.config = config

    def forward(self, pixel_values: torch.Tensor) -> torch.Tensor:
        batch_size, num_channels, height, width = pixel_values.shape
        embeddings = self.patch_embeddings(pixel_values)

        batch_size, seq_len, _ = embeddings.size()

        # add the [CLS] and detection tokens to the embedded patch tokens
        cls_tokens = self.cls_token.expand(batch_size, -1, -1)
        detection_tokens = self.detection_tokens.expand(batch_size, -1, -1)
        embeddings = torch.cat((cls_tokens, embeddings, detection_tokens), dim=1)

        # add positional encoding to each token
        # this might require interpolation of the existing position embeddings
        position_embeddings = self.interpolation(self.position_embeddings, (height, width))

        embeddings = embeddings + position_embeddings
        embeddings = self.dropout(embeddings)

        return embeddings


class InterpolateInitialPositionEmbeddings(nn.Module):
    def __init__(self, config) -> None:
        super().__init__()
        self.config = config

    def forward(self, pos_embed, img_size=(800, 1344)) -> torch.Tensor:
        cls_pos_embed = pos_embed[:, 0, :]
        cls_pos_embed = cls_pos_embed[:, None]
        det_pos_embed = pos_embed[:, -self.config.num_detection_tokens :, :]
        patch_pos_embed = pos_embed[:, 1 : -self.config.num_detection_tokens, :]
        patch_pos_embed = patch_pos_embed.transpose(1, 2)
        batch_size, hidden_size, seq_len = patch_pos_embed.shape

        patch_height, patch_width = (
            self.config.image_size[0] // self.config.patch_size,
            self.config.image_size[1] // self.config.patch_size,
        )
        patch_pos_embed = patch_pos_embed.view(batch_size, hidden_size, patch_height, patch_width)

        height, width = img_size
        new_patch_height, new_patch_width = height // self.config.patch_size, width // self.config.patch_size
        patch_pos_embed = nn.functional.interpolate(
            patch_pos_embed, size=(new_patch_height, new_patch_width), mode="bicubic", align_corners=False
        )
        patch_pos_embed = patch_pos_embed.flatten(2).transpose(1, 2)
        scale_pos_embed = torch.cat((cls_pos_embed, patch_pos_embed, det_pos_embed), dim=1)
        return scale_pos_embed


class InterpolateMidPositionEmbeddings(nn.Module):
    def __init__(self, config) -> None:
        super().__init__()
        self.config = config

    def forward(self, pos_embed, img_size=(800, 1344)) -> torch.Tensor:
        cls_pos_embed = pos_embed[:, :, 0, :]
        cls_pos_embed = cls_pos_embed[:, None]
        det_pos_embed = pos_embed[:, :, -self.config.num_detection_tokens :, :]
        patch_pos_embed = pos_embed[:, :, 1 : -self.config.num_detection_tokens, :]
        patch_pos_embed = patch_pos_embed.transpose(2, 3)
        depth, batch_size, hidden_size, seq_len = patch_pos_embed.shape

        patch_height, patch_width = (
            self.config.image_size[0] // self.config.patch_size,
            self.config.image_size[1] // self.config.patch_size,
        )
        patch_pos_embed = patch_pos_embed.view(depth * batch_size, hidden_size, patch_height, patch_width)
        height, width = img_size
        new_patch_height, new_patch_width = height // self.config.patch_size, width // self.config.patch_size
        patch_pos_embed = nn.functional.interpolate(
            patch_pos_embed, size=(new_patch_height, new_patch_width), mode="bicubic", align_corners=False
        )
        patch_pos_embed = (
            patch_pos_embed.flatten(2)
            .transpose(1, 2)
            .contiguous()
            .view(depth, batch_size, new_patch_height * new_patch_width, hidden_size)
        )
        scale_pos_embed = torch.cat((cls_pos_embed, patch_pos_embed, det_pos_embed), dim=2)
        return scale_pos_embed


class YolosPatchEmbeddings(nn.Module):
    """
    This class turns `pixel_values` of shape `(batch_size, num_channels, height, width)` into the initial
    `hidden_states` (patch embeddings) of shape `(batch_size, seq_length, hidden_size)` to be consumed by a
    Transformer.
    """

    def __init__(self, config):
        super().__init__()
        image_size, patch_size = config.image_size, config.patch_size
        num_channels, hidden_size = config.num_channels, config.hidden_size

        image_size = image_size if isinstance(image_size, collections.abc.Iterable) else (image_size, image_size)
        patch_size = patch_size if isinstance(patch_size, collections.abc.Iterable) else (patch_size, patch_size)
        num_patches = (image_size[1] // patch_size[1]) * (image_size[0] // patch_size[0])
        self.image_size = image_size
        self.patch_size = patch_size
        self.num_channels = num_channels
        self.num_patches = num_patches

        self.projection = nn.Conv2d(num_channels, hidden_size, kernel_size=patch_size, stride=patch_size)

    def forward(self, pixel_values: torch.Tensor) -> torch.Tensor:
        batch_size, num_channels, height, width = pixel_values.shape
        if num_channels != self.num_channels:
            raise ValueError(
                "Make sure that the channel dimension of the pixel values match with the one set in the configuration."
            )

        embeddings = self.projection(pixel_values).flatten(2).transpose(1, 2)
        return embeddings


# Copied from transformers.models.bert.modeling_bert.eager_attention_forward
def eager_attention_forward(
    module: nn.Module,
    query: torch.Tensor,
    key: torch.Tensor,
    value: torch.Tensor,
    attention_mask: torch.Tensor | None,
    scaling: float | None = None,
    dropout: float = 0.0,
    **kwargs: Unpack[TransformersKwargs],
):
    if scaling is None:
        scaling = query.size(-1) ** -0.5

    # Take the dot product between "query" and "key" to get the raw attention scores.
    attn_weights = torch.matmul(query, key.transpose(2, 3)) * scaling

    if attention_mask is not None:
        attn_weights = attn_weights + attention_mask

    attn_weights = nn.functional.softmax(attn_weights, dim=-1)
    attn_weights = nn.functional.dropout(attn_weights, p=dropout, training=module.training)

    attn_output = torch.matmul(attn_weights, value)
    attn_output = attn_output.transpose(1, 2).contiguous()

    return attn_output, attn_weights


# Copied from transformers.models.vit.modeling_vit.ViTSelfAttention with ViT->Yolos
class YolosSelfAttention(nn.Module):
    def __init__(self, config: YolosConfig):
        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.config = config
        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.dropout_prob = config.attention_probs_dropout_prob
        self.scaling = self.attention_head_size**-0.5
        self.is_causal = False

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

    def forward(
        self,
        hidden_states: torch.Tensor,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple[torch.Tensor, torch.Tensor]:
        batch_size = hidden_states.shape[0]
        new_shape = batch_size, -1, self.num_attention_heads, self.attention_head_size

        key_layer = self.key(hidden_states).view(*new_shape).transpose(1, 2)
        value_layer = self.value(hidden_states).view(*new_shape).transpose(1, 2)
        query_layer = self.query(hidden_states).view(*new_shape).transpose(1, 2)

        attention_interface: Callable = ALL_ATTENTION_FUNCTIONS.get_interface(
            self.config._attn_implementation, eager_attention_forward
        )

        context_layer, attention_probs = attention_interface(
            self,
            query_layer,
            key_layer,
            value_layer,
            None,
            is_causal=self.is_causal,
            scaling=self.scaling,
            dropout=0.0 if not self.training else self.dropout_prob,
            **kwargs,
        )

        new_context_layer_shape = context_layer.size()[:-2] + (self.all_head_size,)
        context_layer = context_layer.reshape(new_context_layer_shape)

        return context_layer, attention_probs


# Copied from transformers.models.vit.modeling_vit.ViTSelfOutput with ViT->Yolos
class YolosSelfOutput(nn.Module):
    """
    The residual connection is defined in YolosLayer instead of here (as is the case with other models), due to the
    layernorm applied before each block.
    """

    def __init__(self, config: YolosConfig):
        super().__init__()
        self.dense = nn.Linear(config.hidden_size, config.hidden_size)
        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)
        return hidden_states


# Copied from transformers.models.vit.modeling_vit.ViTAttention with ViT->Yolos
class YolosAttention(nn.Module):
    def __init__(self, config: YolosConfig):
        super().__init__()
        self.attention = YolosSelfAttention(config)
        self.output = YolosSelfOutput(config)

    def forward(
        self,
        hidden_states: torch.Tensor,
        **kwargs: Unpack[TransformersKwargs],
    ) -> torch.Tensor:
        self_attn_output, _ = self.attention(hidden_states, **kwargs)
        output = self.output(self_attn_output, hidden_states)
        return output


# Copied from transformers.models.vit.modeling_vit.ViTIntermediate with ViT->Yolos
class YolosIntermediate(nn.Module):
    def __init__(self, config: YolosConfig):
        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.vit.modeling_vit.ViTOutput with ViT->Yolos
class YolosOutput(nn.Module):
    def __init__(self, config: YolosConfig):
        super().__init__()
        self.dense = nn.Linear(config.intermediate_size, config.hidden_size)
        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 = hidden_states + input_tensor
        return hidden_states


# Copied from transformers.models.vit.modeling_vit.ViTLayer with ViT->Yolos,VIT->YOLOS
class YolosLayer(GradientCheckpointingLayer):
    """This corresponds to the Block class in the timm implementation."""

    def __init__(self, config: YolosConfig):
        super().__init__()
        self.chunk_size_feed_forward = config.chunk_size_feed_forward
        self.seq_len_dim = 1
        self.attention = YolosAttention(config)
        self.intermediate = YolosIntermediate(config)
        self.output = YolosOutput(config)
        self.layernorm_before = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.layernorm_after = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)

    def forward(
        self,
        hidden_states: torch.Tensor,
        **kwargs: Unpack[TransformersKwargs],
    ) -> torch.Tensor:
        hidden_states_norm = self.layernorm_before(hidden_states)
        attention_output = self.attention(hidden_states_norm, **kwargs)

        # first residual connection
        hidden_states = attention_output + hidden_states

        # in Yolos, layernorm is also applied after self-attention
        layer_output = self.layernorm_after(hidden_states)
        layer_output = self.intermediate(layer_output)

        # second residual connection is done here
        layer_output = self.output(layer_output, hidden_states)

        return layer_output


class YolosEncoder(nn.Module):
    def __init__(self, config: YolosConfig) -> None:
        super().__init__()
        self.config = config
        self.layer = nn.ModuleList([YolosLayer(config) for _ in range(config.num_hidden_layers)])
        self.gradient_checkpointing = False

        seq_length = (
            1 + (config.image_size[0] * config.image_size[1] // config.patch_size**2) + config.num_detection_tokens
        )
        self.mid_position_embeddings = (
            nn.Parameter(
                torch.zeros(
                    config.num_hidden_layers - 1,
                    1,
                    seq_length,
                    config.hidden_size,
                )
            )
            if config.use_mid_position_embeddings
            else None
        )

        self.interpolation = InterpolateMidPositionEmbeddings(config) if config.use_mid_position_embeddings else None

    def forward(
        self,
        hidden_states: torch.Tensor,
        height: int,
        width: int,
    ) -> BaseModelOutput:
        if self.config.use_mid_position_embeddings:
            interpolated_mid_position_embeddings = self.interpolation(self.mid_position_embeddings, (height, width))

        for i, layer_module in enumerate(self.layer):
            hidden_states = layer_module(hidden_states)

            if self.config.use_mid_position_embeddings:
                if i < (self.config.num_hidden_layers - 1):
                    hidden_states = hidden_states + interpolated_mid_position_embeddings[i]

        return BaseModelOutput(last_hidden_state=hidden_states)


@auto_docstring
class YolosPreTrainedModel(PreTrainedModel):
    config: YolosConfig
    base_model_prefix = "vit"
    main_input_name = "pixel_values"
    input_modalities = ("image",)
    supports_gradient_checkpointing = True
    _no_split_modules = []
    _supports_sdpa = True
    _supports_flash_attn = True
    _supports_flex_attn = True
    _supports_attention_backend = True
    _can_record_outputs = {
        "hidden_states": YolosLayer,
        "attentions": YolosSelfAttention,
    }


@auto_docstring
class YolosModel(YolosPreTrainedModel):
    def __init__(self, config: YolosConfig, add_pooling_layer: bool = True):
        r"""
        add_pooling_layer (bool, *optional*, defaults to `True`):
            Whether to add a pooling layer
        """
        super().__init__(config)
        self.config = config

        self.embeddings = YolosEmbeddings(config)
        self.encoder = YolosEncoder(config)

        self.layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.pooler = YolosPooler(config) if add_pooling_layer else None

        # Initialize weights and apply final processing
        self.post_init()

    def get_input_embeddings(self) -> YolosPatchEmbeddings:
        return self.embeddings.patch_embeddings

    @merge_with_config_defaults
    @capture_outputs(tie_last_hidden_states=False)
    @auto_docstring
    def forward(
        self,
        pixel_values: torch.Tensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> BaseModelOutputWithPooling:
        if pixel_values is None:
            raise ValueError("You have to specify pixel_values")

        embedding_output = self.embeddings(pixel_values)

        height, width = pixel_values.shape[-2:]
        encoder_outputs: BaseModelOutput = self.encoder(embedding_output, height=height, width=width)
        sequence_output = encoder_outputs.last_hidden_state
        sequence_output = self.layernorm(sequence_output)
        pooled_output = self.pooler(sequence_output) if self.pooler is not None else None

        return BaseModelOutputWithPooling(last_hidden_state=sequence_output, pooler_output=pooled_output)


class YolosPooler(nn.Module):
    def __init__(self, config: YolosConfig):
        super().__init__()
        self.dense = nn.Linear(config.hidden_size, config.hidden_size)
        self.activation = nn.Tanh()

    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
        # We "pool" the model by simply taking the hidden state corresponding
        # to the first token.
        first_token_tensor = hidden_states[:, 0]
        pooled_output = self.dense(first_token_tensor)
        pooled_output = self.activation(pooled_output)
        return pooled_output


# Copied from transformers.models.detr.modeling_detr.DetrMLPPredictionHead with Detr->Yolos
class YolosMLPPredictionHead(nn.Module):
    """
    Very simple multi-layer perceptron (MLP, also called FFN), used to predict the normalized center coordinates,
    height and width of a bounding box w.r.t. an image.

    """

    def __init__(self, input_dim, hidden_dim, output_dim, num_layers):
        super().__init__()
        self.num_layers = num_layers
        h = [hidden_dim] * (num_layers - 1)
        self.layers = nn.ModuleList(nn.Linear(n, k) for n, k in zip([input_dim] + h, h + [output_dim]))

    def forward(self, x):
        for i, layer in enumerate(self.layers):
            x = nn.functional.relu(layer(x)) if i < self.num_layers - 1 else layer(x)
        return x


@auto_docstring(
    custom_intro="""
    YOLOS Model (consisting of a ViT encoder) with object detection heads on top, for tasks such as COCO detection.
    """
)
class YolosForObjectDetection(YolosPreTrainedModel):
    def __init__(self, config: YolosConfig):
        super().__init__(config)

        # YOLOS (ViT) encoder model
        self.vit = YolosModel(config, add_pooling_layer=False)

        # Object detection heads
        # We add one for the "no object" class
        self.class_labels_classifier = YolosMLPPredictionHead(
            input_dim=config.hidden_size, hidden_dim=config.hidden_size, output_dim=config.num_labels + 1, num_layers=3
        )
        self.bbox_predictor = YolosMLPPredictionHead(
            input_dim=config.hidden_size, hidden_dim=config.hidden_size, output_dim=4, num_layers=3
        )

        # Initialize weights and apply final processing
        self.post_init()

    # taken from https://github.com/facebookresearch/detr/blob/master/models/detr.py
    def _set_aux_loss(self, outputs_class, outputs_coord):
        return [{"logits": a, "pred_boxes": b} for a, b in zip(outputs_class[:-1], outputs_coord[:-1])]

    @can_return_tuple
    @auto_docstring
    def forward(
        self,
        pixel_values: torch.FloatTensor,
        labels: list[dict] | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> YolosObjectDetectionOutput:
        r"""
        labels (`list[Dict]` of len `(batch_size,)`, *optional*):
            Labels for computing the bipartite matching loss. List of dicts, each dictionary containing at least the
            following 2 keys: `'class_labels'` and `'boxes'` (the class labels and bounding boxes of an image in the
            batch respectively). The class labels themselves should be a `torch.LongTensor` of len `(number of bounding
            boxes in the image,)` and the boxes a `torch.FloatTensor` of shape `(number of bounding boxes in the image,
            4)`.

        Examples:

        ```python
        >>> from transformers import AutoImageProcessor, AutoModelForObjectDetection
        >>> import torch
        >>> from PIL import Image
        >>> import httpx
        >>> from io import BytesIO

        >>> url = "http://images.cocodataset.org/val2017/000000039769.jpg"
        >>> with httpx.stream("GET", url) as response:
        ...     image = Image.open(BytesIO(response.read()))

        >>> image_processor = AutoImageProcessor.from_pretrained("hustvl/yolos-tiny")
        >>> model = AutoModelForObjectDetection.from_pretrained("hustvl/yolos-tiny")

        >>> inputs = image_processor(images=image, return_tensors="pt")
        >>> outputs = model(**inputs)

        >>> # convert outputs (bounding boxes and class logits) to Pascal VOC format (xmin, ymin, xmax, ymax)
        >>> target_sizes = torch.tensor([image.size[::-1]])
        >>> results = image_processor.post_process_object_detection(outputs, threshold=0.9, target_sizes=target_sizes)[
        ...     0
        ... ]

        >>> for score, label, box in zip(results["scores"], results["labels"], results["boxes"]):
        ...     box = [round(i, 2) for i in box.tolist()]
        ...     print(
        ...         f"Detected {model.config.id2label[label.item()]} with confidence "
        ...         f"{round(score.item(), 3)} at location {box}"
        ...     )
        Detected remote with confidence 0.991 at location [46.48, 72.78, 178.98, 119.3]
        Detected remote with confidence 0.908 at location [336.48, 79.27, 368.23, 192.36]
        Detected cat with confidence 0.934 at location [337.18, 18.06, 638.14, 373.09]
        Detected cat with confidence 0.979 at location [10.93, 53.74, 313.41, 470.67]
        Detected remote with confidence 0.974 at location [41.63, 72.23, 178.09, 119.99]
        ```"""

        # First, sent images through YOLOS base model to obtain hidden states
        outputs: BaseModelOutputWithPooling = self.vit(pixel_values, **kwargs)
        sequence_output = outputs.last_hidden_state

        # Take the final hidden states of the detection tokens
        sequence_output = sequence_output[:, -self.config.num_detection_tokens :, :]

        # Class logits + predicted bounding boxes
        logits = self.class_labels_classifier(sequence_output)
        pred_boxes = self.bbox_predictor(sequence_output).sigmoid()

        loss, loss_dict, auxiliary_outputs = None, None, None
        if labels is not None:
            outputs_class, outputs_coord = None, None
            if self.config.auxiliary_loss:
                intermediate = outputs.hidden_states
                outputs_class = self.class_labels_classifier(intermediate)
                outputs_coord = self.bbox_predictor(intermediate).sigmoid()
            loss, loss_dict, auxiliary_outputs = self.loss_function(
                logits, labels, self.device, pred_boxes, self.config, outputs_class, outputs_coord
            )

        return YolosObjectDetectionOutput(
            loss=loss,
            loss_dict=loss_dict,
            logits=logits,
            pred_boxes=pred_boxes,
            auxiliary_outputs=auxiliary_outputs,
            last_hidden_state=outputs.last_hidden_state,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
        )


__all__ = ["YolosForObjectDetection", "YolosModel", "YolosPreTrainedModel"]