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RepVGG

Repvgg: Making vgg-style convnets great again

Abstract

We present a simple but powerful architecture of convolutional neural network, which has a VGG-like inference-time body composed of nothing but a stack of 3x3 convolution and ReLU, while the training-time model has a multi-branch topology. Such decoupling of the training-time and inference-time architecture is realized by a structural re-parameterization technique so that the model is named RepVGG. On ImageNet, RepVGG reaches over 80% top-1 accuracy, which is the first time for a plain model, to the best of our knowledge. On NVIDIA 1080Ti GPU, RepVGG models run 83% faster than ResNet-50 or 101% faster than ResNet-101 with higher accuracy and show favorable accuracy-speed trade-off compared to the state-of-the-art models like EfficientNet and RegNet.

Results and models

ImageNet-1k

Model	Epochs	Params(M)	Flops(G)	Top-1 (%)	Top-5 (%)	Config	Download
RepVGG-A0*	120	9.11（train) | 8.31 (deploy)	1.52 (train) | 1.36 (deploy)	72.41	90.50	config (train) | config (deploy)	model
RepVGG-A1*	120	14.09 (train) | 12.79 (deploy)	2.64 (train) | 2.37 (deploy)	74.47	91.85	config (train) | config (deploy)	model
RepVGG-A2*	120	28.21 (train) | 25.5 (deploy)	5.7 (train) | 5.12 (deploy)	76.48	93.01	config (train) |config (deploy)	model
RepVGG-B0*	120	15.82 (train) | 14.34 (deploy)	3.42 (train) | 3.06 (deploy)	75.14	92.42	config (train) |config (deploy)	model
RepVGG-B1*	120	57.42 (train) | 51.83 (deploy)	13.16 (train) | 11.82 (deploy)	78.37	94.11	config (train) |config (deploy)	model
RepVGG-B1g2*	120	45.78 (train) | 41.36 (deploy)	9.82 (train) | 8.82 (deploy)	77.79	93.88	config (train) |config (deploy)	model
RepVGG-B1g4*	120	39.97 (train) | 36.13 (deploy)	8.15 (train) | 7.32 (deploy)	77.58	93.84	config (train) |config (deploy)	model
RepVGG-B2*	120	89.02 (train) | 80.32 (deploy)	20.46 (train) | 18.39 (deploy)	78.78	94.42	config (train) |config (deploy)	model
RepVGG-B2g4*	200	61.76 (train) | 55.78 (deploy)	12.63 (train) | 11.34 (deploy)	79.38	94.68	config (train) |config (deploy)	model
RepVGG-B3*	200	123.09 (train) | 110.96 (deploy)	29.17 (train) | 26.22 (deploy)	80.52	95.26	config (train) |config (deploy)	model
RepVGG-B3g4*	200	83.83 (train) | 75.63 (deploy)	17.9 (train) | 16.08 (deploy)	80.22	95.10	config (train) |config (deploy)	model
RepVGG-D2se*	200	133.33 (train) | 120.39 (deploy)	36.56 (train) | 32.85 (deploy)	81.81	95.94	config (train) |config (deploy)	model

Models with * are converted from the official repo. The config files of these models are only for validation. We don’t ensure these config files’ training accuracy and welcome you to contribute your reproduction results.

How to use

The checkpoints provided are all training-time models. Use the reparameterize tool to switch them to more efficient inference-time architecture, which not only has fewer parameters but also less calculations.

Use tool

Use provided tool to reparameterize the given model and save the checkpoint:

python tools/convert_models/reparameterize_model.py ${CFG_PATH} ${SRC_CKPT_PATH} ${TARGET_CKPT_PATH}

${CFG_PATH} is the config file, ${SRC_CKPT_PATH} is the source chenpoint file, ${TARGET_CKPT_PATH} is the target deploy weight file path.

To use reparameterized weights, the config file must switch to the deploy config files.

python tools/test.py ${Deploy_CFG} ${Deploy_Checkpoint} --metrics accuracy

In the code

Use backbone.switch_to_deploy() or classificer.backbone.switch_to_deploy() to switch to the deploy mode. For example:

from mmcls.models import build_backbone

backbone_cfg=dict(type='RepVGG',arch='A0'),
backbone = build_backbone(backbone_cfg)
backbone.switch_to_deploy()

or

from mmcls.models import build_classifier

cfg = dict(
    type='ImageClassifier',
    backbone=dict(
        type='RepVGG',
        arch='A0'),
    neck=dict(type='GlobalAveragePooling'),
    head=dict(
        type='LinearClsHead',
        num_classes=1000,
        in_channels=1280,
        loss=dict(type='CrossEntropyLoss', loss_weight=1.0),
        topk=(1, 5),
    ))

classifier = build_classifier(cfg)
classifier.backbone.switch_to_deploy()

Citation

@inproceedings{ding2021repvgg,
  title={Repvgg: Making vgg-style convnets great again},
  author={Ding, Xiaohan and Zhang, Xiangyu and Ma, Ningning and Han, Jungong and Ding, Guiguang and Sun, Jian},
  booktitle={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition},
  pages={13733--13742},
  year={2021}
}