Dassl is a PyTorch toolbox designed for researching Domain Adaptation and Semi-Supervised Learning (and hence the name Dassl). It has a modular design and unified interfaces, allowing fast prototyping and experimentation of new DA/SSL methods. With Dassl, a new method can be implemented with only a few lines of code.

You can use Dassl as a library for the following research:

• Domain adaptation
• Domain generalization
• Semi-supervised learning

• [Jul 2021]: v0.3.4: Adds a new function generate_fewshot_dataset() to the base dataset class, which allows for the generation of a few-shot learning setting. One can customize a few-shot dataset by specifying _C.DATASET.NUM_SHOTS and give it to generate_fewshot_dataset().
• [Jul 2021]: v0.3.2: Adds _C.INPUT.INTERPOLATION (default: bilinear). Available interpolation modes are bilinear, nearest, and bicubic.
• [Jul 2021] v0.3.1: Now you can use *.register(force=True) to replace previously registered modules.
• [Jul 2021] v0.3.0: Allows to deploy the model with the best validation performance for final test (for the purpose of model selection). Specifically, a new config variable named _C.TEST.FINAL_MODEL is introduced, which takes either "last_step" (default) or "best_val". When set to "best_val", the model will be evaluated on the val set after each epoch and the one with the best validation performance will be saved and used for final test (see this code).
• [Jul 2021] v0.2.7: Adds attribute classnames to the base dataset class. Now you can get a list of class names ordered by numeric labels by calling trainer.dm.dataset.classnames.
• [Jun 2021] v0.2.6: Merges MixStyle2 to MixStyle. A new variable self.mix is used to switch between random mixing and cross-domain mixing. Please see this for more details on the new features.
• [Jun 2021] v0.2.5: Fixs a bug in the calculation of per-class recognition accuracy.
• [Jun 2021] v0.2.4: Adds extend_cfg(cfg) to train.py. This function is particularly useful when you build your own methods on top of Dassl.pytorch and need to define some custom variables. Please see the repository mixstyle-release or ssdg-benchmark for examples.
• [Jun 2021] New benchmarks for semi-supervised domain generalization at https://github.com/KaiyangZhou/ssdg-benchmark.
• [Apr 2021] Do you know you can use tools/parse_test_res.py to read the log files and automatically calculate and print out the results including mean and standard deviation? Check the instructions in tools/parse_test_res.py for more details.

Dassl has implemented the following methods:

• Single-source domain adaptation

  • Semi-supervised Domain Adaptation via Minimax Entropy (ICCV'19) [dassl/engine/da/mme.py]
  • Maximum Classifier Discrepancy for Unsupervised Domain Adaptation (CVPR'18) [dassl/engine/da/mcd.py]
  • Self-ensembling for visual domain adaptation (ICLR'18) [dassl/engine/da/self_ensembling.py]
  • Revisiting Batch Normalization For Practical Domain Adaptation (ICLR-W'17) [dassl/engine/da/adabn.py]
  • Adversarial Discriminative Domain Adaptation (CVPR'17) [dassl/engine/da/adda.py]
  • Domain-Adversarial Training of Neural Networks (JMLR'16) [dassl/engine/da/dann.py]

• Multi-source domain adaptation

  • Domain Aadaptive Ensemble Learning [dassl/engine/da/dael.py]
  • Moment Matching for Multi-Source Domain Adaptation (ICCV'19) [dassl/engine/da/m3sda.py]

• Domain generalization

  • Domain Generalization with MixStyle (ICLR'21) [dassl/modeling/ops/mixstyle.py]
  • Deep Domain-Adversarial Image Generation for Domain Generalisation (AAAI'20) [dassl/engine/dg/ddaig.py]
  • Generalizing Across Domains via Cross-Gradient Training (ICLR'18) [dassl/engine/dg/crossgrad.py]

• Semi-supervised learning

  • FixMatch: Simplifying Semi-Supervised Learning with Consistency and Confidence [dassl/engine/ssl/fixmatch.py]
  • MixMatch: A Holistic Approach to Semi-Supervised Learning (NeurIPS'19) [dassl/engine/ssl/mixmatch.py]
  • Mean teachers are better role models: Weight-averaged consistency targets improve semi-supervised deep learning results (NeurIPS'17) [dassl/engine/ssl/mean_teacher.py]
  • Semi-supervised Learning by Entropy Minimization (NeurIPS'04) [dassl/engine/ssl/entmin.py]

Feel free to make a PR to add your methods here to make it easier for others to benchmark!

Dassl supports the following datasets:

• Domain adaptation

  • Office-31
  • Office-Home
  • VisDA17
  • CIFAR10-STL10
  • Digit-5
  • DomainNet
  • miniDomainNet

• Domain generalization

  • PACS
  • VLCS
  • Office-Home
  • Digits-DG
  • Digit-Single
  • CIFAR-10-C
  • CIFAR-100-C

• Semi-supervised learning

  • CIFAR10/100
  • SVHN
  • STL10

Make sure conda is installed properly.

# Clone this repo
git clone https://github.com/KaiyangZhou/Dassl.pytorch.git
cd Dassl.pytorch/

# Create a conda environment
conda create -n dassl python=3.7

# Activate the environment
conda activate dassl

# Install dependencies
pip install -r requirements.txt

# Install torch (version >= 1.7.1) and torchvision
conda install pytorch torchvision cudatoolkit=10.1 -c pytorch

# Install this library (no need to re-build if the source code is modified)
python setup.py develop

Follow the instructions in DATASETS.md to preprocess the datasets.

The main interface is implemented in tools/train.py, which basically does

1. initialize the config with cfg = setup_cfg(args) where args contains the command-line input (see tools/train.py for the list of input arguments);
2. instantiate a trainer with build_trainer(cfg) which loads the dataset and builds a deep neural network model;
3. call trainer.train() for training and evaluating the model.

Below we provide an example for training a source-only baseline on the popular domain adaptation dataset, Office-31,

CUDA_VISIBLE_DEVICES=0 python tools/train.py \
--root $DATA \
--trainer SourceOnly \
--source-domains amazon \
--target-domains webcam \
--dataset-config-file configs/datasets/da/office31.yaml \
--config-file configs/trainers/da/source_only/office31.yaml \
--output-dir output/source_only_office31

$DATA denotes the location where datasets are installed. --dataset-config-file loads the common setting for the dataset (Office-31 in this case) such as image size and model architecture. --config-file loads the algorithm-specific setting such as hyper-parameters and optimization parameters.

To use multiple sources, namely the multi-source domain adaptation task, one just needs to add more sources to --source-domains. For instance, to train a source-only baseline on miniDomainNet, one can do

CUDA_VISIBLE_DEVICES=0 python tools/train.py \
--root $DATA \
--trainer SourceOnly \
--source-domains clipart painting real \
--target-domains sketch \
--dataset-config-file configs/datasets/da/mini_domainnet.yaml \
--config-file configs/trainers/da/source_only/mini_domainnet.yaml \
--output-dir output/source_only_minidn

After the training finishes, the model weights will be saved under the specified output directory, along with a log file and a tensorboard file for visualization.

To print out the results saved in the log file (so you do not need to exhaustively go through all log files and calculate the mean/std by yourself), you can use tools/parse_test_res.py. The instruction can be found in the code.

For other trainers such as MCD, you can set --trainer MCD while keeping the config file unchanged, i.e. using the same training parameters as SourceOnly (in the simplest case). To modify the hyper-parameters in MCD, like N_STEP_F (number of steps to update the feature extractor), you can append TRAINER.MCD.N_STEP_F 4 to the existing input arguments (otherwise the default value will be used). Alternatively, you can create a new .yaml config file to store your custom setting. See here for a complete list of algorithm-specific hyper-parameters.

Model testing can be done by using --eval-only, which asks the code to run trainer.test(). You also need to provide the trained model and specify which model file (i.e. saved at which epoch) to use. For example, to use model.pth.tar-20 saved at output/source_only_office31/model, you can do

CUDA_VISIBLE_DEVICES=0 python tools/train.py \
--root $DATA \
--trainer SourceOnly \
--source-domains amazon \
--target-domains webcam \
--dataset-config-file configs/datasets/da/office31.yaml \
--config-file configs/trainers/da/source_only/office31.yaml \
--output-dir output/source_only_office31_test \
--eval-only \
--model-dir output/source_only_office31 \
--load-epoch 20

Note that --model-dir takes as input the directory path which was specified in --output-dir in the training stage.

A good practice is to go through dassl/engine/trainer.py to get familar with the base trainer classes, which provide generic functions and training loops. To write a trainer class for domain adaptation or semi-supervised learning, the new class can subclass TrainerXU. For domain generalization, the new class can subclass TrainerX. In particular, TrainerXU and TrainerX mainly differ in whether using a data loader for unlabeled data. With the base classes, a new trainer may only need to implement the forward_backward() method, which performs loss computation and model update. See dassl/enigne/da/source_only.py for example.

backbone corresponds to a convolutional neural network model which performs feature extraction. head (which is an optional module) is mounted on top of backbone for further processing, which can be, for example, a MLP. backbone and head are basic building blocks for constructing a SimpleNet() (see dassl/engine/trainer.py) which serves as the primary model for a task. network contains custom neural network models, such as an image generator.

To add a new module, namely a backbone/head/network, you need to first register the module using the corresponding registry, i.e. BACKBONE_REGISTRY for backbone, HEAD_REGISTRY for head and NETWORK_RESIGTRY for network. Note that for a new backbone, we require the model to subclass Backbone as defined in dassl/modeling/backbone/backbone.py and specify the self._out_features attribute.

We provide an example below for how to add a new backbone.

from dassl.modeling import Backbone, BACKBONE_REGISTRY

class MyBackbone(Backbone):

    def __init__(self):
        super().__init__()
        # Create layers
        self.conv = ...

        self._out_features = 2048

    def forward(self, x):
        # Extract and return features

@BACKBONE_REGISTRY.register()
def my_backbone(**kwargs):
    return MyBackbone()

Then, you can set MODEL.BACKBONE.NAME to my_backbone to use your own architecture. For more details, please refer to the source code in dassl/modeling.

If you find this code useful to your research, please give credit to the following paper

@article{zhou2020domain,
  title={Domain Adaptive Ensemble Learning},
  author={Zhou, Kaiyang and Yang, Yongxin and Qiao, Yu and Xiang, Tao},
  journal={arXiv preprint arXiv:2003.07325},
  year={2020}
}