ImageNet training in PyTorch
This implements training of popular model architectures, such as ResNet, AlexNet, and VGG on the ImageNet dataset.
Requirements
- Install PyTorch (pytorch.org)
pip install -r requirements.txt- 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
Training
To train a model, run main.py with the desired model architecture and the path to the ImageNet dataset:
python main.py -a resnet18 [imagenet-folder with train and val folders]The default learning rate schedule starts at 0.1 and decays by a factor of 10 every 30 epochs. This is appropriate for ResNet and models with batch normalization, but too high for AlexNet and VGG. Use 0.01 as the initial learning rate for AlexNet or VGG:
python main.py -a alexnet --lr 0.01 [imagenet-folder with train and val folders]Multi-processing Distributed Data Parallel Training
You should always use the NCCL backend for multi-processing distributed training since it currently provides the best distributed training performance.
Single node, multiple GPUs:
python main.py -a resnet50 --dist-url 'tcp://127.0.0.1:FREEPORT' --dist-backend 'nccl' --multiprocessing-distributed --world-size 1 --rank 0 [imagenet-folder with train and val folders]Multiple nodes:
Node 0:
python main.py -a resnet50 --dist-url 'tcp://IP_OF_NODE0:FREEPORT' --dist-backend 'nccl' --multiprocessing-distributed --world-size 2 --rank 0 [imagenet-folder with train and val folders]Node 1:
python main.py -a resnet50 --dist-url 'tcp://IP_OF_NODE0:FREEPORT' --dist-backend 'nccl' --multiprocessing-distributed --world-size 2 --rank 1 [imagenet-folder with train and val folders]Usage
usage: main.py [-h] [--arch ARCH] [-j N] [--epochs N] [--start-epoch N] [-b N]
[--lr LR] [--momentum M] [--weight-decay W] [--print-freq N]
[--resume PATH] [-e] [--pretrained] [--world-size WORLD_SIZE]
[--rank RANK] [--dist-url DIST_URL]
[--dist-backend DIST_BACKEND] [--seed SEED] [--gpu GPU]
[--multiprocessing-distributed]
DIR
PyTorch ImageNet Training
positional arguments:
DIR path to dataset
optional arguments:
-h, --help show this help message and exit
--arch ARCH, -a ARCH model architecture: alexnet | densenet121 |
densenet161 | densenet169 | densenet201 |
resnet101 | resnet152 | resnet18 | resnet34 |
resnet50 | squeezenet1_0 | squeezenet1_1 | vgg11 |
vgg11_bn | vgg13 | vgg13_bn | vgg16 | vgg16_bn | vgg19
| vgg19_bn (default: resnet18)
-j N, --workers N number of data loading workers (default: 4)
--epochs N number of total epochs to run
--start-epoch N manual epoch number (useful on restarts)
-b N, --batch-size N mini-batch size (default: 256), this is the total
batch size of all GPUs on the current node when using
Data Parallel or Distributed Data Parallel
--lr LR, --learning-rate LR
initial learning rate
--momentum M momentum
--weight-decay W, --wd W
weight decay (default: 1e-4)
--print-freq N, -p N print frequency (default: 10)
--resume PATH path to latest checkpoint (default: none)
-e, --evaluate evaluate model on validation set
--pretrained use pre-trained model
--world-size WORLD_SIZE
number of nodes for distributed training
--rank RANK node rank for distributed training
--dist-url DIST_URL url used to set up distributed training
--dist-backend DIST_BACKEND
distributed backend
--seed SEED seed for initializing training.
--gpu GPU GPU id to use.
--multiprocessing-distributed
Use multi-processing distributed training to launch N
processes per node, which has N GPUs. This is the
fastest way to use PyTorch for either single node or
multi node data parallel training