Post-Training Sparsity-Aware Quantization

This repository is the official implementation of Post-Training Sparsity-Aware Quantization.

@article{shomron2021sparq,
  title={Post-Training Sparsity-Aware Quantization},
  author={Shomron, Gil and Gabbay, Freddy and Kurzum, Samer and Weiser, Uri},
  journal={arXiv preprint arXiv:2105.11010},
  year={2021}
}

Requirements

Install PyTorch. Specifically, we use version 1.5.1 with CUDA 10.1.

pip install torch==1.5.1+cu101 torchvision==0.6.1+cu101 -f https://download.pytorch.org/whl/torch_stable.html

Pick PyTorch 1.5.1 with the appropriate CUDA version from the official PyTorch website.
Then, install the other packages and our custom CUDA package:

pip install -r requirements.txt
cd cu_gemm_2x48
python ./setup install

The ImageNet path, as well as the seeds used to achieve the paper's results, are configured in Config.py.
Throughout this work, we used Ubuntu 18.04, Python 3.6.9, and NVIDIA TITAN V GPU.

8-bit Model Quantization

SPARQ operates on top 8-bit models. To quantize the models, execute the following command:

python ./main.py -a resnet18_imagenet --action QUANTIZE --x_bits 8 --w_bits 8

We support the following models: resnet18_imagenet, resnet34_imagenet, resnet50_imagenet, resnet101_imagenet, googlenet_imagenet, inception_imagenet, densenet_imagenet.

SPARQ Evaluation

To evaluate the quantized models, execute the following:

python ./main.py -a resnet18_imagenet
                 --action INFERENCE
                 --chkp [PATH^]
                 --x_bits 8 --w_bits 8
                 --eval --round_mode RAW --shift_opt 5 --bit_group 4

where round_mode is either RAW or ROUND, shift_opt correspond to opt5, opt3, and op2, and bit_group correspond to 4, 3, and 2 window bit-width.

[^] PATH points to the quantized model and is relative to the data/results folder.
[^^] shift_opt 5 when paired with bit_group 3 and 2 correspond to opt6 and opt7, respectively.
[^^^] In the paper, we used --batch_size 32 with InceptionV3.

Pre-trained 2:4 Pruned Models

Models were trained using this PyTorch script and NVIDIA ASP library. We used 90 epochs with a learning rate starting from 0.1 and divided by 10 on epochs 30 and 60. Weight decay and momentum are set to 0.0001 and 0.9, respectively. The pruned models can be downloaded from the links in the table below.

Model	Top-1	Download
ResNet-18	69.77%	Link
ResNet-50	76.16%	Link
ResNet-101	77.38%	Link

To evaluate SPARQ on top of the pruned models, quantize the models as before, and add --stc flag to the evaluation command line.