Geometric Sensitivity Decomposition

1. This repo is the official implementation of A Geometric Perspective towards Neural Calibration via Sensitivity Decomposition (tian21gsd). The pape is accpted at NeurIPS 2021. as a spotlight paper.
2. We reimplememented Exploring Covariate and Concept Shift for Out-of-Distribution Detection (tian21explore) and include it in the code base as well. The paper is accepted at NeurIPS 2021 workshop on Distribution Shift.
3. For a brief introduction to these two papers, please visit the project page.

Create conda environment

conda env create -f requirements.yaml
conda activate gsd

Training

1. Dataset will be automatically downloaded in the ./datasets directory the first time.
2. We provide support for CIFAR10 and CIFAR100. Please change name in the configuration file accordingly (default: CIFAR10).

data: 
    name: cifar10 

3. Three sample training configuration files are provided.

   • To train a vanilla model.

     python train.py --config ./configs/train/resnet_vanilla.yaml   
     

   • To train the GSD model proposed in tian21gsd.

     python train.py --config ./configs/train/resnet_gsd.yaml   
     

   • To train the Geometric ODIN model proposed in tian21exploring.

     python train.py --config ./configs/train/resnet_geo_odin.yaml   
     

Evaluation

1, We provide support for evaluation on CIFAR10, CIFAR100, CIFAR10C, CIFAR100C and SVHN. We consider both out-of-distribution (OOD) detection and confidence calibration. Models trained on different datasets will use different evaluation datasets.

	OOD detection				Calibration
Training	Near OOD		Far OOD	Special	ID	OOD
CIFAR10	CIFAR10C	CIFAR100	SVHN	CIFAR100 Splits	CIFAR10	CIFAR10C
CIFAR100	CIFAR100C	CIFAR10	SVHN		CIFAR100	CIFAR100C

2. The eval.py file optionally calibrates a model. It 1) evaluates calibration performance and 2) saves several scores for OOD detection evaluation later.

   • Run the following commend to evaluate on a test set.

     python eval.py --config ./configs/eval/resnet_{model}.yaml 
     

   • To specify a calibration method, select the calibration attribute out of supported ones (use 'none' to avoid calibration). Note that a vanilla model can be calibrated using three supported methods, temperature scaling, matrix scaling and dirichlet scaling. GSD and Geometric ODIN use the alpha-beta scaling.

         testing: 
             calibration: temperature # ['temperature','dirichlet','matrix','alpha-beta','none'] 

   • To select a testing dataset, modify the dataset attribute. Note that the calibration dataset (specified under data: name) can be different than the testing dataset.

         testing: 
             dataset: cifar10 # cifar10, cifar100, cifar100c, cifar10c, svhn testing dataset

3. Calibration benchmark

   • Results will be saved under ./runs/test/{data_name}/{arch}/{calibration}/{test_dataset}_calibration.txt.
   • We use Expected Calibration Error (ECE), Negative Log Likelihood and Brier score for calibration evaluation.
   • We recommend using a 5-fold evalution for in-distribution (ID) calibration benchmark because CIFAR10/100 does not have a val/test split. Note that evalx.py does not save OOD scores.

     python evalx.py --config ./configs/train/resnet_{model}.yaml 
     

   • (Optional) To use the proposed exponential mapping (tian21gsd) for calibration, set the attribute exponential_map to 0.1.

4. Out-of-Distribution (OOD) benchmark

   • OOD evaluation needs to run eval.py two times to extract OOD scores from both the ID and OOD datasets.
   • Results will be saved under ./runs/test/{data_name}/{arch}/{calibration}/{test_dataset}_scores.csv. For example, to evaluate OOD detection performance of a vanilla model (ID:CIFAR10 vs. OOD:CIFAR10C), you need to run eval.py twice on CIFAR10 and CIFAR10C as the testing dataset. Upon completion, you will see two files, cifar10_scores.csv and cifar10c_scores.csv in the same folder.
   • After the evaluation results are saved, to calculate OOD detection performance, run calculate_ood.py and specify the conditions of the model: training set, testing set, model name and calibration method. The flags will help the function locate csv files saved in the previous step.

     python utils/calculate_ood.py --train cifar10 --test cifar10c --model resnet_vanilla --calibration none
     

   • We use AUROC and TNR@TPR95 as evaluation metrics.

Performance

1. confidence calibration Performance of models trained on CIFAR10

	accuracy		ECE		Nll
	CIFAR10	CIFAR10C	CIFAR10	CIFAR10C	CIFAR10	CIFAR10C
Vanilla	96.25	69.43	0.0151	0.1433	0.1529	1.0885
Temperature Scaling	96.02	71.54	0.0028	0.0995	0.1352	0.8699
Dirichlet Scaling	95.93	71.15	0.0049	0.1135	0.1305	0.9527
GSD (tian21gsd)	96.23	71.7	0.0057	0.0439	0.1431	0.7921
Geometric ODIN (tian21explore)	95.92	70.18	0.0016	0.0454	0.1309	0.8138

2. Out-of-Distribution Detection Performance (AUROC) of models trained on CIFAR10

AUROC	score function	CIFAR100	CIFAR10C	SVHN
Vanilla	MSP	88.33	71.49	91.88
	Energy	88.11	71.94	92.88
GSD (tian21gsd)	U	92.68	77.68	99.29
Geometric ODIN (tian21explore)	U	92.53	78.77	99.60

Additional Resources

1. Pretrained models
   • vanilla wide ResNet
   • GSD wide ResNet
   • Geometric ODIN wide ResNet