open-mmlab/mmdetection · info

'num_dn_queries' should be set when using dynamic dn groups,

Error message

'num_dn_queries' should be set when using dynamic dn groups, use 100 as default.

What it means

DINO's CdnQueryGenerator warns that dynamic denoising group config lacks num_dn_queries and falls back to 100 noised queries per image. With dynamic groups, num_dn_queries (rather than num_groups alone) controls how many DN queries are generated.

Source

Thrown at mmdet/models/layers/transformer/dino_layers.py:166

                 num_classes: int,
                 embed_dims: int,
                 num_matching_queries: int,
                 label_noise_scale: float = 0.5,
                 box_noise_scale: float = 1.0,
                 group_cfg: OptConfigType = None) -> None:
        super().__init__()
        self.num_classes = num_classes
        self.embed_dims = embed_dims
        self.num_matching_queries = num_matching_queries
        self.label_noise_scale = label_noise_scale
        self.box_noise_scale = box_noise_scale

        # prepare grouping strategy
        group_cfg = {} if group_cfg is None else group_cfg
        self.dynamic_dn_groups = group_cfg.get('dynamic', True)
        if self.dynamic_dn_groups:
            if 'num_dn_queries' not in group_cfg:
                warnings.warn("'num_dn_queries' should be set when using "
                              'dynamic dn groups, use 100 as default.')
            self.num_dn_queries = group_cfg.get('num_dn_queries', 100)
            assert isinstance(self.num_dn_queries, int), \
                f'Expected the num_dn_queries to have type int, but got ' \
                f'{self.num_dn_queries}({type(self.num_dn_queries)}). '
        else:
            assert 'num_groups' in group_cfg, \
                'num_groups should be set when using static dn groups'
            self.num_groups = group_cfg['num_groups']
            assert isinstance(self.num_groups, int), \
                f'Expected the num_groups to have type int, but got ' \
                f'{self.num_groups}({type(self.num_groups)}). '

        # NOTE The original repo of DINO set the num_embeddings 92 for coco,
        # 91 (0~90) of which represents target classes and the 92 (91)
        # indicates `Unknown` class. However, the embedding of `unknown` class
        # is not used in the original DINO.
        # TODO: num_classes + 1 or num_classes ?

View on GitHub (pinned to cfd5d3a985)

Solutions

1. Add num_dn_queries (e.g. 100) to group_cfg explicitly
2. Or set dynamic=False to use static num_groups behavior

Example fix

# before
dn_cfg=dict(group_cfg=dict(dynamic=True, num_groups=5))
# after
dn_cfg=dict(group_cfg=dict(dynamic=True, num_dn_queries=100, num_groups=5))

group_cfg = cfg.setdefault('group_cfg', {})
if group_cfg.get('dynamic', True):
    group_cfg.setdefault('num_dn_queries', 100)  # set explicitly to silence

When it happens

Trigger: Configuring DINO/Deformable-DETR-with-DINO with group_cfg=dict(dynamic=True) but no num_dn_queries key.

Common situations: Custom DINO configs copied from docs where group_cfg only sets num_groups; porting configs across mmdet versions.

Related errors

• DETR do not build sampler.
• Invalid text mode "{self.text_mode}".
• The type of frame_range must be int or list.
• results does not contain masks.
• {metric} is not in results

AI-assisted analysis of open-mmlab/mmdetection@cfd5d3a985 (2026-08-27). Data as JSON: /api/errors/dc9e03740849790f. Report an issue: GitHub.