Filter Pruning via Geometric Median for Deep Convolutional Neural Networks Acceleration

CVPR 2019 Oral.

Implementation with PyTorch. This implementation is based on soft-filter-pruning.

What's New

FPGM has been re-implemented in Pytorch and NNI.

Usage in Pytorch

from torch.ao.sparsity.pruning._experimental.pruner import FPGM_pruner

# set network-level sparsity: all layers have a sparsity level of 30%
pruner = FPGMPruner(sparsity_level = 0.3)

# set layer-level sparsity: sparsity_level of conv2d1 = 30%, sparsity_level of conv2d2 = 50%
config = [
    {"tensor_fqn": "conv2d1.weight"},
    {"tensor_fqn": "conv2d2.weight", "sparsity_level": 0.5}
]

pruner.prepare(model, config)
pruner.enable_mask_update = True
pruner.step()

# Get real pruned models (without zeros)
pruned_model = pruner.prune()

See source code here and official test code here.

Usage in NNI

from nni.algorithms.compression.pytorch.pruning import FPGMPruner
config_list = [{
    'sparsity': 0.5,
    'op_types': ['Conv2d']
}]
pruner = FPGMPruner(model, config_list)
pruner.compress()

See explanation here.

Table of Contents

• Requirements
• Models and log files
• Training ResNet on ImageNet
  • Usage of Pruning Training
  • Usage of Normal Training
  • Inference the pruned model with zeros
  • Inference the pruned model without zeros
  • Scripts to reproduce the results in our paper
• Training ResNet on Cifar-10
• Training VGGNet on Cifar-10
• Notes
  • Torchvision Version
  • Why use 100 epochs for training
  • Process of ImageNet dataset
  • FLOPs Calculation
• Citation

Requirements

• Python 3.6
• PyTorch 0.3.1
• TorchVision 0.3.0

Models and log files

The trained models with log files can be found in Google Drive. Specifically:

models for pruning ResNet on ImageNet

models for pruning ResNet on CIFAR-10

models for pruning VGGNet on CIFAR-10

models for ablation study

The pruned model without zeros, refer to this issue.

Training ResNet on ImageNet

Usage of Pruning Training

We train each model from scratch by default. If you wish to train the model with pre-trained models, please use the options --use_pretrain --lr 0.01.

Run Pruning Training ResNet (depth 152,101,50,34,18) on Imagenet:

python pruning_imagenet.py -a resnet152 --save_path ./snapshots/resnet152-rate-0.7 --rate_norm 1 --rate_dist 0.4 --layer_begin 0 --layer_end 462 --layer_inter 3  /path/to/Imagenet2012

python pruning_imagenet.py -a resnet101 --save_path ./snapshots/resnet101-rate-0.7 --rate_norm 1 --rate_dist 0.4 --layer_begin 0 --layer_end 309 --layer_inter 3  /path/to/Imagenet2012

python pruning_imagenet.py -a resnet50  --save_path ./snapshots/resnet50-rate-0.7 --rate_norm 1 --rate_dist 0.4 --layer_begin 0 --layer_end 156 --layer_inter 3  /path/to/Imagenet2012

python pruning_imagenet.py -a resnet34  --save_path ./snapshots/resnet34-rate-0.7 --rate_norm 1 --rate_dist 0.4 --layer_begin 0 --layer_end 105 --layer_inter 3  /path/to/Imagenet2012

python pruning_imagenet.py -a resnet18  --save_path ./snapshots/resnet18-rate-0.7 --rate_norm 1 --rate_dist 0.4 --layer_begin 0 --layer_end 57 --layer_inter 3  /path/to/Imagenet2012

Explanation:

Note1: rate_norm = 0.9 means pruning 10% filters by norm-based criterion, rate_dist = 0.2 means pruning 20% filters by distance-based criterion.

Note2: the layer_begin and layer_end is the index of the first and last conv layer, layer_inter choose the conv layer instead of BN layer.

Usage of Normal Training

Run resnet(100 epochs):

python original_train.py -a resnet50 --save_dir ./snapshots/resnet50-baseline  /path/to/Imagenet2012 --workers 36

Inference the pruned model with zeros

sh function/inference_pruned.sh

Inference the pruned model without zeros

The pruned model without zeros, refer to this issue.

Scripts to reproduce the results in our paper

To train the ImageNet model with / without pruning, see the directory scripts. Full script is here.

Training ResNet on Cifar-10

sh scripts/pruning_cifar10.sh

Please be care of the hyper-parameter layer_end for different layer of ResNet.

Reproduce ablation study of Cifar-10:

sh scripts/ablation_pruning_cifar10.sh

Training VGGNet on Cifar-10

Refer to the directory VGG_cifar.

Reproduce previous paper Pruning Filters for Efficient ConvNets

sh VGG_cifar/scripts/PFEC_train_prune.sh

Four function included in the script, including training baseline, pruning from pretrain, pruning from scratch, finetune the pruend

Our method

sh VGG_cifar/scripts/pruning_vgg_my_method.sh

Including pruning the pretrained, pruning the scratch.

Notes

Torchvision Version

We use the torchvision of 0.3.0. If the version of your torchvision is 0.2.0, then the transforms.RandomResizedCrop should be transforms.RandomSizedCrop and the transforms.Resize should be transforms.Scale.

Why use 100 epochs for training

This can improve the accuracy slightly.

Process of ImageNet dataset

We follow the Facebook process of ImageNet. Two subfolders ("train" and "val") are included in the "/path/to/ImageNet2012". The correspding code is here.

FLOPs Calculation

Refer to the file.

Citation

@inproceedings{he2019filter,
  title     = {Filter Pruning via Geometric Median for Deep Convolutional Neural Networks Acceleration},
  author    = {He, Yang and Liu, Ping and Wang, Ziwei and Hu, Zhilan and Yang, Yi},
  booktitle = {Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR)},
  year      = {2019}
}