engine/deim/deim_decoder.py

"""
DEIM: DETR with Improved Matching for Fast Convergence
Copyright (c) 2024 The DEIM Authors. All Rights Reserved.
---------------------------------------------------------------------------------
Modified from D-FINE (https://github.com/Peterande/D-FINE/)
Copyright (c) 2024 D-FINE Authors. All Rights Reserved.
"""

import math
import copy
import functools
from collections import OrderedDict

import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.nn.init as init
from typing import List

from ..core import register
from .denoising import get_contrastive_denoising_training_group
from .utils import deformable_attention_core_func_v2, get_activation, inverse_sigmoid, bias_init_with_prob

from .dfine_decoder import MSDeformableAttention, LQE, Integral
from .dfine_utils import weighting_function, distance2bbox
from .deim_utils import RMSNorm, SwiGLUFFN, Gate, MLP

__all__ = ['DEIMTransformer']


class TransformerDecoderLayer(nn.Module):
    def __init__(self,
                 d_model=256,
                 n_head=8,
                 dim_feedforward=1024,
                 dropout=0.,
                 activation='relu',
                 n_levels=4,
                 n_points=4,
                 cross_attn_method='default',
                 layer_scale=None,
                 use_gateway=False,
                 ):
        super(TransformerDecoderLayer, self).__init__()

        if layer_scale is not None:
            print(f"     --- Wide Layer@{layer_scale} ---")
            dim_feedforward = round(layer_scale * dim_feedforward)
            d_model = round(layer_scale * d_model)

        # self attention
        self.self_attn = nn.MultiheadAttention(d_model, n_head, dropout=dropout, batch_first=True)
        self.dropout1 = nn.Dropout(dropout)
        self.norm1 = RMSNorm(d_model)

        # cross attention
        self.cross_attn = MSDeformableAttention(d_model, n_head, n_levels, n_points, method=cross_attn_method)
        self.dropout2 = nn.Dropout(dropout)

        self.use_gateway = use_gateway
        if use_gateway:
            self.gateway = Gate(d_model, use_rmsnorm=True)
        else:
            self.norm2 = RMSNorm(d_model)

        # ffn
        self.swish_ffn = SwiGLUFFN(d_model, dim_feedforward // 2, d_model)
        self.dropout4 = nn.Dropout(dropout)
        self.norm3 = RMSNorm(d_model)

    def with_pos_embed(self, tensor, pos):
        return tensor if pos is None else tensor + pos

    def forward(self,
                target,
                reference_points,
                value,
                spatial_shapes,
                attn_mask=None,
                query_pos_embed=None):

        # self attention
        q = k = self.with_pos_embed(target, query_pos_embed)

        target2, _ = self.self_attn(q, k, value=target, attn_mask=attn_mask)
        target = target + self.dropout1(target2)
        target = self.norm1(target)

        # cross attention
        target2 = self.cross_attn(\
            self.with_pos_embed(target, query_pos_embed),
            reference_points,
            value,
            spatial_shapes)

        if self.use_gateway:
            target = self.gateway(target, self.dropout2(target2))
        else:
            target = target + self.dropout2(target2)
            target = self.norm2(target)

        # ffn
        target2 = self.swish_ffn(target)
        target = target + self.dropout4(target2)
        target = self.norm3(target.clamp(min=-65504, max=65504))

        return target


class TransformerDecoder(nn.Module):
    """
    Transformer Decoder implementing Fine-grained Distribution Refinement (FDR).

    This decoder refines object detection predictions through iterative updates across multiple layers,
    utilizing attention mechanisms, location quality estimators, and distribution refinement techniques
    to improve bounding box accuracy and robustness.
    """

    def __init__(self, hidden_dim, decoder_layer, decoder_layer_wide, num_layers, num_head, reg_max, reg_scale, up,
                 eval_idx=-1, layer_scale=2, act='relu'):
        super(TransformerDecoder, self).__init__()
        self.hidden_dim = hidden_dim
        self.num_layers = num_layers
        self.layer_scale = layer_scale
        self.num_head = num_head
        self.eval_idx = eval_idx if eval_idx >= 0 else num_layers + eval_idx
        self.up, self.reg_scale, self.reg_max = up, reg_scale, reg_max
        self.layers = nn.ModuleList([copy.deepcopy(decoder_layer) for _ in range(self.eval_idx + 1)] \
                    + [copy.deepcopy(decoder_layer_wide) for _ in range(num_layers - self.eval_idx - 1)])
        self.lqe_layers = nn.ModuleList([copy.deepcopy(LQE(4, 64, 2, reg_max, act=act)) for _ in range(num_layers)])

    def value_op(self, memory, value_proj, value_scale, memory_mask, memory_spatial_shapes):
        """
        Preprocess values for MSDeformableAttention.
        """
        value = value_proj(memory) if value_proj is not None else memory
        value = F.interpolate(memory, size=value_scale) if value_scale is not None else value
        if memory_mask is not None:
            value = value * memory_mask.to(value.dtype).unsqueeze(-1)
        value = value.reshape(value.shape[0], value.shape[1], self.num_head, -1)
        split_shape = [h * w for h, w in memory_spatial_shapes]
        return value.permute(0, 2, 3, 1).split(split_shape, dim=-1)

    def convert_to_deploy(self):
        self.project = weighting_function(self.reg_max, self.up, self.reg_scale, deploy=True)
        self.layers = self.layers[:self.eval_idx + 1]
        self.lqe_layers = nn.ModuleList([nn.Identity()] * (self.eval_idx) + [self.lqe_layers[self.eval_idx]])

    def forward(self,
                target,
                ref_points_unact,
                memory,
                spatial_shapes,
                bbox_head,
                score_head,
                query_pos_head,
                pre_bbox_head,
                integral,
                up,
                reg_scale,
                attn_mask=None,
                memory_mask=None,
                dn_meta=None):
        output = target
        output_detach = pred_corners_undetach = 0
        value = self.value_op(memory, None, None, memory_mask, spatial_shapes)

        dec_out_bboxes = []
        dec_out_logits = []
        dec_out_pred_corners = []
        dec_out_refs = []
        if not hasattr(self, 'project'):
            project = weighting_function(self.reg_max, up, reg_scale)
        else:
            project = self.project

        ref_points_detach = F.sigmoid(ref_points_unact)
        query_pos_embed = query_pos_head(ref_points_detach).clamp(min=-10, max=10)

        for i, layer in enumerate(self.layers):
            ref_points_input = ref_points_detach.unsqueeze(2)

            if i >= self.eval_idx + 1 and self.layer_scale > 1:
                query_pos_embed = F.interpolate(query_pos_embed, scale_factor=self.layer_scale)
                value = self.value_op(memory, None, query_pos_embed.shape[-1], memory_mask, spatial_shapes)
                output = F.interpolate(output, size=query_pos_embed.shape[-1])
                output_detach = output.detach()

            output = layer(output, ref_points_input, value, spatial_shapes, attn_mask, query_pos_embed)

            if i == 0 :
                # Initial bounding box predictions with inverse sigmoid refinement
                pre_bboxes = F.sigmoid(pre_bbox_head(output) + inverse_sigmoid(ref_points_detach))
                pre_scores = score_head[0](output)
                ref_points_initial = pre_bboxes.detach()

            # Refine bounding box corners using FDR, integrating previous layer's corrections
            pred_corners = bbox_head[i](output + output_detach) + pred_corners_undetach
            inter_ref_bbox = distance2bbox(ref_points_initial, integral(pred_corners, project), reg_scale)

            if self.training or i == self.eval_idx:
                scores = score_head[i](output)
                # Lqe does not affect the performance here.
                scores = self.lqe_layers[i](scores, pred_corners)
                dec_out_logits.append(scores)
                dec_out_bboxes.append(inter_ref_bbox)
                dec_out_pred_corners.append(pred_corners)
                dec_out_refs.append(ref_points_initial)

                if not self.training:
                    break

            pred_corners_undetach = pred_corners
            ref_points_detach = inter_ref_bbox.detach()
            output_detach = output.detach()

        return torch.stack(dec_out_bboxes), torch.stack(dec_out_logits), \
               torch.stack(dec_out_pred_corners), torch.stack(dec_out_refs), pre_bboxes, pre_scores


@register()
class DEIMTransformer(nn.Module):
    __share__ = ['num_classes', 'eval_spatial_size']

    def __init__(self,
                 num_classes=80,
                 hidden_dim=256,
                 num_queries=300,
                 feat_channels=[512, 1024, 2048],
                 feat_strides=[8, 16, 32],
                 num_levels=3,
                 num_points=4,
                 nhead=8,
                 num_layers=6,
                 dim_feedforward=1024,
                 dropout=0.,
                 activation="relu",
                 num_denoising=100,
                 label_noise_ratio=0.5,
                 box_noise_scale=1.0,
                 learn_query_content=False,
                 eval_spatial_size=None,
                 eval_idx=-1,
                 eps=1e-2,
                 aux_loss=True,
                 cross_attn_method='default',
                 query_select_method='default',
                 reg_max=32,
                 reg_scale=4.,
                 layer_scale=1,
                 mlp_act='relu',
                 use_gateway=True,
                 share_bbox_head=False,
                 share_score_head=False,
                 ):
        super().__init__()
        assert len(feat_channels) <= num_levels
        assert len(feat_strides) == len(feat_channels)

        for _ in range(num_levels - len(feat_strides)):
            feat_strides.append(feat_strides[-1] * 2)

        self.hidden_dim = hidden_dim
        scaled_dim = round(layer_scale*hidden_dim)
        self.nhead = nhead
        self.feat_strides = feat_strides
        self.num_levels = num_levels
        self.num_classes = num_classes
        self.num_queries = num_queries
        self.eps = eps
        self.num_layers = num_layers
        self.eval_spatial_size = eval_spatial_size
        self.aux_loss = aux_loss
        self.reg_max = reg_max

        assert query_select_method in ('default', 'one2many', 'agnostic'), ''
        assert cross_attn_method in ('default', 'discrete'), ''
        self.cross_attn_method = cross_attn_method
        self.query_select_method = query_select_method
        # -- print the parameters
        print(f"     --- Use Gateway@{use_gateway} ---")
        print(f"     --- Use Share Bbox Head@{share_bbox_head} ---")
        print(f"     --- Use Share Score Head@{share_score_head} ---")

        # backbone feature projection
        self._build_input_proj_layer(feat_channels)

        # Transformer module
        self.up = nn.Parameter(torch.tensor([0.5]), requires_grad=False)
        self.reg_scale = nn.Parameter(torch.tensor([reg_scale]), requires_grad=False)
        decoder_layer = TransformerDecoderLayer(hidden_dim, nhead, dim_feedforward, dropout, \
            activation, num_levels, num_points, cross_attn_method=cross_attn_method, use_gateway=use_gateway)
        decoder_layer_wide = TransformerDecoderLayer(hidden_dim, nhead, dim_feedforward, dropout, \
            activation, num_levels, num_points, cross_attn_method=cross_attn_method, layer_scale=layer_scale, use_gateway=use_gateway)
        self.decoder = TransformerDecoder(hidden_dim, decoder_layer, decoder_layer_wide, num_layers, nhead,
                                          reg_max, self.reg_scale, self.up, eval_idx, layer_scale, act=activation)
      # denoising
        self.num_denoising = num_denoising
        self.label_noise_ratio = label_noise_ratio
        self.box_noise_scale = box_noise_scale
        if num_denoising > 0:
            self.denoising_class_embed = nn.Embedding(num_classes+1, hidden_dim, padding_idx=num_classes)
            init.normal_(self.denoising_class_embed.weight[:-1])

        # decoder embedding
        self.learn_query_content = learn_query_content
        if learn_query_content:
            self.tgt_embed = nn.Embedding(num_queries, hidden_dim)

        if query_select_method == 'agnostic':
            self.enc_score_head = nn.Linear(hidden_dim, 1)
        else:
            self.enc_score_head = nn.Linear(hidden_dim, num_classes)
        self.enc_bbox_head = MLP(hidden_dim, hidden_dim, 4, 3, act=mlp_act)

        self.query_pos_head = MLP(4, hidden_dim, hidden_dim, 3, act=mlp_act)

        # decoder head
        self.pre_bbox_head = MLP(hidden_dim, hidden_dim, 4, 3, act=mlp_act)
        self.integral = Integral(self.reg_max)

        self.eval_idx = eval_idx if eval_idx >= 0 else num_layers + eval_idx
        dec_score_head = nn.Linear(hidden_dim, num_classes)
        self.dec_score_head = nn.ModuleList(
            [dec_score_head if share_score_head else copy.deepcopy(dec_score_head) for _ in range(self.eval_idx + 1)]
          + [copy.deepcopy(dec_score_head) for _ in range(num_layers - self.eval_idx - 1)])

        # Share the same bbox head for all layers
        dec_bbox_head = MLP(hidden_dim, hidden_dim, 4 * (self.reg_max+1), 3, act=mlp_act)
        self.dec_bbox_head = nn.ModuleList(
            [dec_bbox_head if share_bbox_head else copy.deepcopy(dec_bbox_head) for _ in range(self.eval_idx + 1)]
          + [MLP(scaled_dim, scaled_dim, 4 * (self.reg_max+1), 3, act=mlp_act) for _ in range(num_layers - self.eval_idx - 1)])

        # init encoder output anchors and valid_mask
        if self.eval_spatial_size:
            anchors, valid_mask = self._generate_anchors()
            self.register_buffer('anchors', anchors)
            self.register_buffer('valid_mask', valid_mask)
        # init encoder output anchors and valid_mask
        if self.eval_spatial_size:
            self.anchors, self.valid_mask = self._generate_anchors()


        self._reset_parameters(feat_channels)

    def convert_to_deploy(self):
        self.dec_score_head = nn.ModuleList([nn.Identity()] * (self.eval_idx) + [self.dec_score_head[self.eval_idx]])
        self.dec_bbox_head = nn.ModuleList(
            [self.dec_bbox_head[i] if i <= self.eval_idx else nn.Identity() for i in range(len(self.dec_bbox_head))]
        )

    def _reset_parameters(self, feat_channels):
        bias = bias_init_with_prob(0.01)
        init.constant_(self.enc_score_head.bias, bias)
        init.constant_(self.enc_bbox_head.layers[-1].weight, 0)
        init.constant_(self.enc_bbox_head.layers[-1].bias, 0)

        init.constant_(self.pre_bbox_head.layers[-1].weight, 0)
        init.constant_(self.pre_bbox_head.layers[-1].bias, 0)

        for cls_, reg_ in zip(self.dec_score_head, self.dec_bbox_head):
            init.constant_(cls_.bias, bias)
            if hasattr(reg_, 'layers'):
                init.constant_(reg_.layers[-1].weight, 0)
                init.constant_(reg_.layers[-1].bias, 0)

        if self.learn_query_content:
            init.xavier_uniform_(self.tgt_embed.weight)
        init.xavier_uniform_(self.query_pos_head.layers[0].weight)
        init.xavier_uniform_(self.query_pos_head.layers[1].weight)
        init.xavier_uniform_(self.query_pos_head.layers[-1].weight)
        for m, in_channels in zip(self.input_proj, feat_channels):
            if in_channels != self.hidden_dim:
                init.xavier_uniform_(m[0].weight)

    def _build_input_proj_layer(self, feat_channels):
        self.input_proj = nn.ModuleList()
        for in_channels in feat_channels:
            if in_channels == self.hidden_dim:
                self.input_proj.append(nn.Identity())
            else:
                self.input_proj.append(
                    nn.Sequential(OrderedDict([
                        ('conv', nn.Conv2d(in_channels, self.hidden_dim, 1, bias=False)),
                        ('norm', nn.BatchNorm2d(self.hidden_dim,))])
                    )
                )

        in_channels = feat_channels[-1]

        for _ in range(self.num_levels - len(feat_channels)):
            if in_channels == self.hidden_dim:
                self.input_proj.append(nn.Identity())
            else:
                self.input_proj.append(
                    nn.Sequential(OrderedDict([
                        ('conv', nn.Conv2d(in_channels, self.hidden_dim, 3, 2, padding=1, bias=False)),
                        ('norm', nn.BatchNorm2d(self.hidden_dim))])
                    )
                )
                in_channels = self.hidden_dim

    def _get_encoder_input(self, feats: List[torch.Tensor]):
        # get projection features
        proj_feats = [self.input_proj[i](feat) for i, feat in enumerate(feats)]
        if self.num_levels > len(proj_feats):
            len_srcs = len(proj_feats)
            for i in range(len_srcs, self.num_levels):
                if i == len_srcs:
                    proj_feats.append(self.input_proj[i](feats[-1]))
                else:
                    proj_feats.append(self.input_proj[i](proj_feats[-1]))

        # get encoder inputs
        feat_flatten = []
        spatial_shapes = []
        for i, feat in enumerate(proj_feats):
            _, _, h, w = feat.shape
            # [b, c, h, w] -> [b, h*w, c]
            feat_flatten.append(feat.flatten(2).permute(0, 2, 1))
            # [num_levels, 2]
            spatial_shapes.append([h, w])

        # [b, l, c]
        feat_flatten = torch.concat(feat_flatten, 1)
        return feat_flatten, spatial_shapes

    def _generate_anchors(self,
                          spatial_shapes=None,
                          grid_size=0.05,
                          dtype=torch.float32,
                          device='cpu'):
        if spatial_shapes is None:
            spatial_shapes = []
            eval_h, eval_w = self.eval_spatial_size
            for s in self.feat_strides:
                spatial_shapes.append([int(eval_h / s), int(eval_w / s)])

        anchors = []
        for lvl, (h, w) in enumerate(spatial_shapes):
            grid_y, grid_x = torch.meshgrid(torch.arange(h), torch.arange(w), indexing='ij')
            grid_xy = torch.stack([grid_x, grid_y], dim=-1)
            grid_xy = (grid_xy.unsqueeze(0) + 0.5) / torch.tensor([w, h], dtype=dtype)
            wh = torch.ones_like(grid_xy) * grid_size * (2.0 ** lvl)
            lvl_anchors = torch.concat([grid_xy, wh], dim=-1).reshape(-1, h * w, 4)
            anchors.append(lvl_anchors)

        anchors = torch.concat(anchors, dim=1).to(device)
        valid_mask = ((anchors > self.eps) * (anchors < 1 - self.eps)).all(-1, keepdim=True)
        anchors = torch.log(anchors / (1 - anchors))
        anchors = torch.where(valid_mask, anchors, torch.inf)

        return anchors, valid_mask


    def _get_decoder_input(self,
                           memory: torch.Tensor,
                           spatial_shapes,
                           denoising_logits=None,
                           denoising_bbox_unact=None):

        # prepare input for decoder
        if self.training or self.eval_spatial_size is None:
            anchors, valid_mask = self._generate_anchors(spatial_shapes, device=memory.device)
        else:
            anchors = self.anchors
            valid_mask = self.valid_mask
        if memory.shape[0] > 1:
            anchors = anchors.repeat(memory.shape[0], 1, 1)

        # memory = torch.where(valid_mask, memory, 0)
        memory = valid_mask.to(memory.dtype) * memory

        enc_outputs_logits :torch.Tensor = self.enc_score_head(memory)

        # select topk queries
        enc_topk_memory, enc_topk_logits, enc_topk_anchors = \
            self._select_topk(memory, enc_outputs_logits, anchors, self.num_queries)

        enc_topk_bbox_unact :torch.Tensor = self.enc_bbox_head(enc_topk_memory) + enc_topk_anchors

        enc_topk_bboxes_list, enc_topk_logits_list = [], []
        if self.training:
            enc_topk_bboxes = F.sigmoid(enc_topk_bbox_unact)
            enc_topk_bboxes_list.append(enc_topk_bboxes)
            enc_topk_logits_list.append(enc_topk_logits)

        if self.learn_query_content:
            content = self.tgt_embed.weight.unsqueeze(0).tile([memory.shape[0], 1, 1])
        else:
            content = enc_topk_memory.detach()

        enc_topk_bbox_unact = enc_topk_bbox_unact.detach()

        if denoising_bbox_unact is not None:
            enc_topk_bbox_unact = torch.concat([denoising_bbox_unact, enc_topk_bbox_unact], dim=1)
            content = torch.concat([denoising_logits, content], dim=1)

        return content, enc_topk_bbox_unact, enc_topk_bboxes_list, enc_topk_logits_list

    def _select_topk(self, memory: torch.Tensor, outputs_logits: torch.Tensor, outputs_anchors_unact: torch.Tensor, topk: int):
        if self.query_select_method == 'default':
            _, topk_ind = torch.topk(outputs_logits.max(-1).values, topk, dim=-1)

        elif self.query_select_method == 'one2many':
            _, topk_ind = torch.topk(outputs_logits.flatten(1), topk, dim=-1)
            topk_ind = topk_ind // self.num_classes

        elif self.query_select_method == 'agnostic':
            _, topk_ind = torch.topk(outputs_logits.squeeze(-1), topk, dim=-1)

        topk_ind: torch.Tensor

        topk_anchors = outputs_anchors_unact.gather(dim=1, \
            index=topk_ind.unsqueeze(-1).repeat(1, 1, outputs_anchors_unact.shape[-1]))

        topk_logits = outputs_logits.gather(dim=1, \
            index=topk_ind.unsqueeze(-1).repeat(1, 1, outputs_logits.shape[-1])) if self.training else None

        topk_memory = memory.gather(dim=1, \
            index=topk_ind.unsqueeze(-1).repeat(1, 1, memory.shape[-1]))

        return topk_memory, topk_logits, topk_anchors

    def forward(self, feats, targets=None):
        # input projection and embedding
        memory, spatial_shapes = self._get_encoder_input(feats)

        # prepare denoising training
        if self.training and self.num_denoising > 0:
            denoising_logits, denoising_bbox_unact, attn_mask, dn_meta = \
                get_contrastive_denoising_training_group(targets, \
                    self.num_classes,
                    self.num_queries,
                    self.denoising_class_embed,
                    num_denoising=self.num_denoising,
                    label_noise_ratio=self.label_noise_ratio,
                    box_noise_scale=1.0,
                    )
        else:
            denoising_logits, denoising_bbox_unact, attn_mask, dn_meta = None, None, None, None

        init_ref_contents, init_ref_points_unact, enc_topk_bboxes_list, enc_topk_logits_list = \
            self._get_decoder_input(memory, spatial_shapes, denoising_logits, denoising_bbox_unact)

        # decoder
        out_bboxes, out_logits, out_corners, out_refs, pre_bboxes, pre_logits = self.decoder(
            init_ref_contents,
            init_ref_points_unact,
            memory,
            spatial_shapes,
            self.dec_bbox_head,
            self.dec_score_head,
            self.query_pos_head,
            self.pre_bbox_head,
            self.integral,
            self.up,
            self.reg_scale,
            attn_mask=attn_mask,
            dn_meta=dn_meta)

        if self.training and dn_meta is not None:
            # the output from the first decoder layer, only one
            dn_pre_logits, pre_logits = torch.split(pre_logits, dn_meta['dn_num_split'], dim=1)
            dn_pre_bboxes, pre_bboxes = torch.split(pre_bboxes, dn_meta['dn_num_split'], dim=1)

            dn_out_logits, out_logits = torch.split(out_logits, dn_meta['dn_num_split'], dim=2)
            dn_out_bboxes, out_bboxes = torch.split(out_bboxes, dn_meta['dn_num_split'], dim=2)

            dn_out_corners, out_corners = torch.split(out_corners, dn_meta['dn_num_split'], dim=2)
            dn_out_refs, out_refs = torch.split(out_refs, dn_meta['dn_num_split'], dim=2)

        if self.training:
            out = {'pred_logits': out_logits[-1], 'pred_boxes': out_bboxes[-1], 'pred_corners': out_corners[-1],
                   'ref_points': out_refs[-1], 'up': self.up, 'reg_scale': self.reg_scale}
        else:
            out = {'pred_logits': out_logits[-1], 'pred_boxes': out_bboxes[-1]}

        if self.training and self.aux_loss:
            out['aux_outputs'] = self._set_aux_loss2(out_logits[:-1], out_bboxes[:-1], out_corners[:-1], out_refs[:-1],
                                                     out_corners[-1], out_logits[-1])
            out['enc_aux_outputs'] = self._set_aux_loss(enc_topk_logits_list, enc_topk_bboxes_list)
            out['pre_outputs'] = {'pred_logits': pre_logits, 'pred_boxes': pre_bboxes}
            out['enc_meta'] = {'class_agnostic': self.query_select_method == 'agnostic'}

            if dn_meta is not None:
                out['dn_outputs'] = self._set_aux_loss2(dn_out_logits, dn_out_bboxes, dn_out_corners, dn_out_refs,
                                                        dn_out_corners[-1], dn_out_logits[-1])
                out['dn_pre_outputs'] = {'pred_logits': dn_pre_logits, 'pred_boxes': dn_pre_bboxes}
                out['dn_meta'] = dn_meta

        return out


    @torch.jit.unused
    def _set_aux_loss(self, outputs_class, outputs_coord):
        # this is a workaround to make torchscript happy, as torchscript
        # doesn't support dictionary with non-homogeneous values, such
        # as a dict having both a Tensor and a list.
        return [{'pred_logits': a, 'pred_boxes': b} for a, b in zip(outputs_class, outputs_coord)]


    @torch.jit.unused
    def _set_aux_loss2(self, outputs_class, outputs_coord, outputs_corners, outputs_ref,
                       teacher_corners=None, teacher_logits=None):
        # this is a workaround to make torchscript happy, as torchscript
        # doesn't support dictionary with non-homogeneous values, such
        # as a dict having both a Tensor and a list.
        return [{'pred_logits': a, 'pred_boxes': b, 'pred_corners': c, 'ref_points': d,
                     'teacher_corners': teacher_corners, 'teacher_logits': teacher_logits}
                for a, b, c, d in zip(outputs_class, outputs_coord, outputs_corners, outputs_ref)]