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iFormer

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iFormer

Category: Efficient/Mobile · Code: timm/models/iformer.py · Architectures: 9 · Pretrained weights: 8 (0 with ImageNet-1k results)

iFormer integrates a fast convolutional network with single-head modulation attention (SHMA) in the later stages, for mobile applications.

Papers

Usage

See the Quickstart for loading pretrained weights, image preprocessing and fine-tuning, and Feature Extraction for using the models as backbones.

>>> import timm
>>> model = timm.create_model('iformer_h.in1k', pretrained=True)
>>> data_config = timm.data.resolve_model_data_config(model)

Model API support

FeatureIFormer
features_only=True feature maps✓ (strides 4, 8, 16, 32)
forward_intermediates()✓
prune_intermediate_layers()✓
Any input size, no changes needed✓
set_input_size()–
dynamic_img_size=True–
set_grad_checkpointing()✓
Layer-wise LR decay (group_matcher())✓
reset_classifier()✓

✓ supported, ✓ (square) works for square sizes only, ✗ not supported, – not needed (the model already accepts any input size). Checked by running each feature on a randomly initialized model (IFormer with iformer_t at 224), other architectures of the same class are expected to behave the same. See the Model API page for details.

Architectures

ArchitectureParams (M)GMACsInput sizePretrained weights
iformer_h99.60-2241
iformer_l14.78-2241
iformer_l224.52-2240
iformer_l2_distilled25.03-2241
iformer_l_distilled15.17-2241
iformer_m8.91-2241
iformer_m_distilled9.29-2241
iformer_s6.56-2241
iformer_t2.89-2241

GMACs and parameter counts are for the default input size and classifier of each architecture, from the benchmark results.

Pretrained weights

Top-1 is ImageNet-1k validation accuracy from results-imagenet.csv at the listed eval size, - if the weight has no ImageNet-1k result (e.g. pretraining or image-text weights). Classes is the size of the pretrained classifier, none for weights without one.

WeightInput sizeTop-1 (%)Eval sizeClassesLicenseHub
iformer_h.in1k224--1000mittimm
iformer_l.in1k224--1000mittimm
iformer_l2_distilled.in1k224--1000mittimm
iformer_l_distilled.in1k224--1000mittimm
iformer_m.in1k224--1000mittimm
iformer_m_distilled.in1k224--1000mittimm
iformer_s.in1k224--1000mittimm
iformer_t.in1k224--1000mittimm

Citation

@inproceedings{zheng2025iformer,
  title={iformer: Integrating convnet and transformer for mobile application},
  author={Zheng, Chuanyang},
  booktitle={International Conference on Learning Representations},
  volume={2025},
  pages={22947--22961},
  year={2025}
}
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