Adan: Adaptive Nesterov Momentum Algorithm for Faster Optimizing Deep Models

This is an official PyTorch implementation of Adan. See paper here. If you find our adan helpful or heuristic to your projects, please cite this paper and also star this repository. Thanks!

@article{xie2022adan,
  title={Adan: Adaptive Nesterov Momentum Algorithm for Faster Optimizing Deep Models},
  author={Xie, Xingyu and Zhou, Pan and Li, Huan and Lin, Zhouchen and Yan, Shuicheng},
  journal={arXiv preprint arXiv:2208.06677},
  year={2022}
}

Usage

For your convenience to use Adan, we briefly provide some intuitive instructions below, then provide some general experimental tips, and finally give more details (e.g. specific commonds and hyper-parameters) for each experiment in the paper.

1) Two steps to use Adan

Step 1. add Adan-dependent hyper-parameters by adding the following hyper-parameters to the config:

parser.add_argument('--max-grad-norm', type=float, default=0.0, help='if the l2 norm is large than this hyper-parameter, then we clip the gradient  (default: 0.0, no gradient clip)')
parser.add_argument('--weight-decay', type=float, default=0.02,  help='weight decay, similar one used in AdamW (default: 0.02)')
parser.add_argument('--opt-eps', default=None, type=float, metavar='EPSILON', help='optimizer epsilon to avoid the bad case where second-order moment is zero (default: None, use opt default 1e-8 in adan)')
parser.add_argument('--opt-betas', default=None, type=float, nargs='+', metavar='BETA', help='optimizer betas in Adan (default: None, use opt default [0.98, 0.92, 0.99] in Adan)')
parser.add_argument('--no-prox', action='store_true', default=False, help='whether perform weight decay like AdamW (default=False)')

opt-betas In order to keep consistent with our usage habits, the $\beta$'s in the paper is actually the $(1-\beta)$'s in the code.

no-prox: It determines the update rule of parameters with weight decay. By default, Adan updates the parameters in the way presented in Algorithm 1 in the paper:

$$\boldsymbol{\theta}_{k+1} = ( 1+\lambda \eta)^{-1}\left[\boldsymbol{\theta}_k - \boldsymbol{\eta}_k \circ (\mathbf{m}_k+(1-{\color{blue}\beta_2})\mathbf{v}k)\right],$$

But one also can update the parameter like Adamw:

$$\boldsymbol{\theta}_{k+1} = ( 1-\lambda \eta)\boldsymbol{\theta}_k - \boldsymbol{\eta}_k \circ (\mathbf{m}_k+(1-{\color{blue}\beta_2})\mathbf{v}_k).$$ In all experiments, we set no-prox=False in our paper.

Step 2. creat the Adan optimizer as follows. In this step, we can directly replace the vanilla optimizer by using the following command:

from adan import Adan
optimizer = Adan(param, lr=args.lr, weight_decay=args.weight_decay, betas=args.opt_betas, eps = args.opt_eps, max_grad_norm=args.max_grad_norm, no_prox=args.no_prox)

2) Tips for Experiments

To make Adan simple, in all experiments except Table 12 in the paper, we do not use the restart strategy in Adan. But Table 12 shows that restart strategy can further slightly improve the performance of Adan.
Adan often allow one to use a large peak learning rate which often fails other optimizers, e.g. Adam and AdamW. For example, in all experiments except for the experiments on MAE pre-training and LSTM, the learning rate used by Adan is 5-10 times than that in Adam/AdamW.
For vision tasks, but not for NLP and RL tasks, it seems that Adan prefers a large batch size for large-scale experiments, e.g. 2,048 total batch size in our paper.
Adan is relatively robust to beta1, beta2 and beta3, especially for beta2. If you hope better performance, you can first tune beta3 and then beta1.
Interestingly, we found that weight_decay = 0.02 is suitable for all experiments in our paper.
In your training, if you already fully use the GPU memory when using other optimizers, then you may need to scale the batch size slightly smaller (accordingly linearly scaling LR, etc.) when using Adan, since Adan has slightly higher GPU memory cost than others.

3) More extra detailed steps to reproduce experimental results in paper

Please refer to the following links for detailed steps. In these detailed steps, we even include the docker images for reproducibility.

Instruction for ViTs, ResNets, and ConvNext.
Instruction for MAE.
Instruction for BERT.
Instruction for Transformer-XL.

Model Zoo

Results on vision tasks

For your convenience to use Adan, we provide the configs and log files for the experiments on ImageNet-1k.

Model	Epoch	Training Setting	Acc. (%)	Config	Batch Size	Download
ViT-S	150	I	80.1	config	2048	log/model
ViT-S	150	II	79.6	config	2048	log/model
ViT-S	300	I	81.1	config	2048	log/model
ViT-S	300	II	80.7	config	2048	log/model
ViT-B	150	II	81.7	config	2048	log/model
ViT-B	300	II	82.3	config	2048	log/model
ResNet-50	100	I	78.1	config	2048	log/model
ResNet-50	200	I	79.7	config	2048	log/model
ResNet-50	300	I	80.2	config	2048	log/model
ConvNext-tiny	150	II	81.7	config	2048	log//model
ConvNext-tiny	300	II	82.4	config	2048	log/model
MAE-small	800+100	---	83.8	config	4096/2048	log-pretrain/log-finetune/model
MAE-Large	800+50	---	85.9	config	4096/2048	log-pretrain/log-finetune/model

Results on NLP tasks

BERT-base

We give the configs and log files of the BERT-base model pre-trained on the Bookcorpus and Wikipedia datasets and fine-tuned on GLUE tasks. Note, we provide the config and log file, and detailed instruction for BERT-base in the folder ./NLP/BERT.

Pretraining	Config	Batch Size	Log	Model
Adan	config	256	log	model

Fine-tuning on GLUE-Task	Metric	Result	Config
CoLA	Matthew's corr.	64.6	config
SST-2	Accuracy	93.2	config
STS-B	Person corr.	89.3	config
QQP	Accuracy	91.2	config
MNLI	Matched acc./Mismatched acc.	85.7/85.6	config
QNLI	Accuracy	91.3	config
RTE	Accuracy	73.3	config

For fine-tuning on GLUE-Task, see the total batch size in their corresponding configure files.

Transformer-XL-base

We provide the config and log for Transformer-XL-base trained on the WikiText-103 dataset. The total batch size for this experiment is 60*4.

	Steps	Test PPL	Download
Baseline (Adam)	200k	24.2	log&config
Transformer-XL-base	50k	26.2	log&config
Transformer-XL-base	100k	24.2	log&config
Transformer-XL-base	200k	23.5	log&config

shengzhang90 / Adan