cxmscb / DemystifyLocalViT

Official code for paper "Demystifying Local Vision Transformer: Sparse Connectivity, Weight Sharing, and Dynamic Weight"

Demysitifing Local Vision Transformer, arxiv

This is the official PyTorch implementation of our paper. We simply replace local self attention by (dynamic) depth-wise convolution with lower computational cost. The performance is on par with the Swin Transformer.

Besides, the main contribution of our paper is the theorical and detailed comparison between depth-wise convolution and local self attention from three aspects: sparse connectivity, weight sharing and dynamic weight. By this paper, we want community to rethinking the local self attention and depth-wise convolution, and the basic model architeture designing rules.

Codes and models for object detection and semantic segmentation are avaliable in Detection and Segmentation.

We also give MLP based Swin Transformer models and Inhomogenous dynamic convolution in the ablation studies. These codes and models will coming soon.

Reference

@article{han2021demystifying,
  title={Demystifying Local Vision Transformer: Sparse Connectivity, Weight Sharing, and Dynamic Weight},
  author={Han, Qi and Fan, Zejia and Dai, Qi and Sun, Lei and Cheng, Ming-Ming and Liu, Jiaying and Wang, Jingdong},
  journal={arXiv preprint arXiv:2106.04263},
  year={2021}
}

1. Requirements

torch>=1.5.0, torchvision, timm, pyyaml; apex-amp

data perpare: ImageNet dataset with the following structure:

│imagenet/
├──train/
│  ├── n01440764
│  │   ├── n01440764_10026.JPEG
│  │   ├── n01440764_10027.JPEG
│  │   ├── ......
│  ├── ......
├──val/
│  ├── n01440764
│  │   ├── ILSVRC2012_val_00000293.JPEG
│  │   ├── ILSVRC2012_val_00002138.JPEG
│  │   ├── ......
│  ├── ......

2. Trainning

For tiny model, we train with batch-size 128 on 8 GPUs. When trainning base model, we use batch-size 64 on 16 GPUs with OpenMPI to keep the total batch-size unchanged. (With the same trainning setting, the base model couldn't train with AMP due to the anomalous gradient values.)

Please change the data path in sh scripts first.

For tiny model:

bash scripts/run_dwnet_tiny_patch4_window7_224.sh 
bash scripts/run_dynamic_dwnet_tiny_patch4_window7_224.sh

For base model, use multi node with OpenMPI:

bash scripts/run_dwnet_base_patch4_window7_224.sh 
bash scripts/run_dynamic_dwnet_base_patch4_window7_224.sh

3. Evaluation

python -m torch.distributed.launch --nproc_per_node 1 --master_port 12345 main.py --cfg configs/change_to_config_file --resume /path/to/model --data-path /path/to/imagenet --eval

4. Models

Models are provided by training on ImageNet with resolution 224.

Model	#params	FLOPs	Top1 Acc	Download
dwnet_tiny	24M	3.8G	81.2	github
dynamic_dwnet_tiny	51M	3.8G	81.8	github
dwnet_base	74M	12.9G	83.2	github
dynamic_dwnet_base	162M	13.0G	83.2	github

Detection (see Detection for details):

Backbone	Pretrain	Lr Schd	box mAP	mask mAP	#params	FLOPs	config	model
DWNet-T	ImageNet-1K	3x	49.9	43.4	82M	730G	config	github
DWNet-B	ImageNet-1K	3x	51.0	44.1	132M	924G	config	github
Dynamic-DWNet-T	ImageNet-1K	3x	50.5	43.7	108M	730G	config	github
Dynamic-DWNet-B	ImageNet-1K	3x	51.2	44.4	219M	924G	config	github

Segmentation (see Segmentation for details):

Backbone	Pretrain	Lr Schd	mIoU	#params	FLOPs	config	model
DWNet-T	ImageNet-1K	160K	45.5	56M	928G	config	github
DWNet-B	ImageNet-1K	160K	48.3	108M	1129G	config	github
Dynamic-DWNet-T	ImageNet-1K	160K	45.7	83M	928G	config	github
Dynamic-DWNet-B	ImageNet-1K	160K	48.0	195M	1129G	config	github

LICENSE

This repo is under the MIT license. Some codes are borrow from Swin Transformer.