HAQ: Hardware-Aware Automated Quantization with Mixed Precision

Introduction

This repo contains PyTorch implementation for paper HAQ: Hardware-Aware Automated Quantization with Mixed Precision (CVPR2019, oral)

@inproceedings{haq,
author = {Wang, Kuan and Liu, Zhijian and Lin, Yujun and Lin, Ji and Han, Song},
title = {HAQ: Hardware-Aware Automated Quantization With Mixed Precision},
booktitle = {IEEE Conference on Computer Vision and Pattern Recognition (CVPR)},
year = {2019}
}

Other papers related to automated model design:

• AMC: AutoML for Model Compression and Acceleration on Mobile Devices (ECCV 2018)

• ProxylessNAS: Direct Neural Architecture Search on Target Task and Hardware (ICLR 2019)

Dependencies

We evaluate this code with Pytorch 1.1 (cuda10) and torchvision 0.3.0, you can install pytorch with conda:

# install pytorch
conda install -y pytorch torchvision cudatoolkit=10.0 -c pytorch

And you can use the following command to set up the environment:

# install packages and download the pretrained model
bash run/setup.sh

(If the server is down, you can download the pretrained model from google drive: mobilenetv2-150.pth.tar)

Current code base is tested under following environment:

1. Python 3.7.3
2. PyTorch 1.1
3. torchvision 0.3.0
4. numpy 1.14
5. matplotlib 3.0.1
6. scikit-learn 0.21.0
7. easydict 1.8
8. progress 1.4
9. tensorboardX 1.7

Dataset

If you already have the ImageNet dataset for pytorch, you could create a link to data folder and use it:

# prepare dataset, change the path to your own
ln -s /path/to/imagenet/ data/

If you do not have the ImageNet yet, you can download the ImageNet dataset and move validation images to labeled subfolders. To do this, you can use the following script: https://raw.githubusercontent.com/soumith/imagenetloader.torch/master/valprep.sh

We use a subset of ImageNet in the linear quantizaiton search phase to save the training time, to create the link of the subset, you can use the following tool:

# prepare imagenet100 dataset
python lib/utils/make_data.py

Reinforcement learning search

• You can run the bash file as following to search the K-Means quantization strategy, which only quantizes the weights with K-Means to compress model size of specific model.

# K-Means quantization, for model size
bash run/run_kmeans_quantize_search.sh

• You can run the bash file as following to search the linear quantization strategy, which linearly quantizes both the weights and activations to reduce latency/energy of specific model.

# Linear quantization, for latency/energy
bash run/run_linear_quantize_search.sh

• Usage details

python rl_quantize.py --help

Finetune Policy

• After searching, you can get the quantization strategy list, and you can replace the strategy list in finetune.py to finetune and evaluate the performance on ImageNet dataset.
• We set the default K-Means quantization strategy searched under preserve ratio = 0.1 like:

# preserve ratio 10%
strategy = [6, 6, 5, 5, 5, 5, 4, 5, 5, 4, 5, 5, 5, 5, 5, 5, 3, 5, 4, 3, 5, 4, 3, 4, 4, 4, 2, 5, 4, 3, 3, 5, 3, 2, 5, 3, 2, 4, 3, 2, 5, 3, 2, 5, 3, 4, 2, 5, 2, 3, 4, 2, 3, 4]

You can follow the following bash file to finetune the K-Means quantized model to get a better performance:

bash run/run_kmeans_quantize_finetune.sh

• We set the default linear quantization strategy searched under preserve ratio = 0.6 like:

# preserve ratio 60%
strategy = [[8, -1], [7, 7], [5, 6], [4, 6], [5, 6], [5, 7], [5, 6], [7, 4], [4, 6], [4, 6], [7, 7], [5, 6], [4, 6], [7, 3], [5, 7], [4, 7], [7, 3], [5, 7], [4, 7], [7, 7], [4, 7], [4, 7], [6, 4], [6, 7], [4, 7], [7, 4], [6, 7], [5, 7], [7, 4], [6, 7], [5, 7], [7, 4], [6, 7], [6, 7], [6, 4], [5, 7], [6, 7], [6, 4], [5, 7], [6, 7], [7, 7], [4, 7], [7, 7], [7, 7], [4, 7], [7, 7], [7, 7], [4, 7], [7, 7], [7, 7], [4, 7], [7, 7], [8, 8]]

You can follow the following bash file to finetune the linear quantized model to get a better performance:

bash run/run_linear_quantize_finetune.sh

• Usage details

python finetune.py --help

Evaluate

You can download the pretrained quantized model like this:

# download checkpoint
mkdir -p checkpoints/resnet50/
mkdir -p checkpoints/mobilenetv2/
cd checkpoints/resnet50/
wget https://hanlab.mit.edu/files/haq/resnet50_0.1_75.48.pth.tar
cd ../mobilenetv2/
wget https://hanlab.mit.edu/files/haq/qmobilenetv2_0.6_71.23.pth.tar
cd ../..

(If the server is down, you can download the pretrained model from google drive: qmobilenetv2_0.6_71.23.pth.tar)

You can evaluate the K-Means quantized model like this:

# evaluate K-Means quantization
bash run/run_kmeans_quantize_eval.sh

Models	preserve ratio	Top1 Acc (%)	Top5 Acc (%)
resnet50 (original)	1.0	76.15	92.87
resnet50 (10x compress)	0.1	75.48	92.42

You can evaluate the linear quantized model like this:

# evaluate linear quantization
bash run/run_linear_quantize_eval.sh

Models	preserve ratio	Top1 Acc (%)	Top5 Acc (%)
mobilenetv2 (original)	1.0	72.05	90.49
mobilenetv2 (0.6x latency)	0.6	71.23	90.00