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awesome-loss-functions

A comprehensive, chronologically ordered collection of loss functions across all subdomains of deep learning and machine learning — with paper links, one-line descriptions, mathema · License unknown · Maintenance unknown

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A comprehensive, chronologically ordered collection of loss functions across all subdomains of deep learning and machine learning — with paper links, one-line descriptions, mathematical formulations, and implementation references.

350+ loss functions. 25+ categories. Every subdomain of AI.

If this resource helps your research or engineering work, please consider giving it a ⭐


What's New

  • 🔊 Audio, Music & Speech Generation — WaveNet to Stable Audio, 19 losses
  • 🎬 Video Generation & Understanding — VGAN to VideoPoet, 20 losses
  • ⏳ Time Series Forecasting — Pinball Loss to TimesFM, 23 losses
  • 🧠 Continual & Lifelong Learning — EWC to EASE, 18 methods
  • ⚖️ Calibration, Fairness & Bias Mitigation — Brier Score to Group DRO, 18 losses
  • 🛡️ Adversarial Robustness & OOD Detection — FGSM-AT to CIDER, 22 losses
  • 🔍 Anomaly Detection & Multi-Modal Learning — Deep SVDD to ImageBind, 17 losses
  • 🖼️ Image-to-Image Translation — Total Variation to DoveNet, 16 losses
  • 📐 Semi-Supervised Learning — Pseudo-Label to SoftMatch, 12 losses
  • 🎯 Optical Flow, Video & Pose — Horn-Schunck to SEA-RAFT, 33 losses

Contents

Core Categories (inline)

Extended Categories (separate files)

Resources


🧭 Loss Selection Guide

Not sure which loss to use? Here's a quick decision framework:

Task Default Choice Class Imbalance Noisy Labels Need Calibration
Binary Classification BCE Focal Loss SCE / GCE Focal + Temp. Scaling
Multi-class Classification Cross-Entropy Class-Balanced CE Label Smoothing Label Smoothing
Semantic Segmentation CE + Dice Focal Tversky — —
Object Detection (box) Smooth L1 + Focal Focal Loss — —
Object Detection (IoU) CIoU / GIoU — — —
Image Generation (GAN) Hinge / Non-Saturating — — —
Image Generation (Diffusion) DDPM (ε-prediction) — — —
Super-Resolution L1 + Perceptual + GAN — — —
Self-Supervised (vision) InfoNCE / DINO — — —
Face Recognition ArcFace / AdaFace Sub-center ArcFace ElasticFace —
Language Modeling Cross-Entropy (NTP) — — —
LLM Alignment DPO / SimPO — — —
Speech Recognition CTC / RNN-T — — —
RL (value-based) DQN / Double DQN — — —
RL (policy-based) PPO — — —
Regression MSE / Huber — Huber NLL w/ variance
Metric Learning Triplet / Proxy Anchor — — —
Medical Segmentation Dice + Boundary Tversky / Focal Tversky — —
3D Reconstruction Chamfer + Normal — — —
Depth Estimation Scale-Invariant — — —
Time Series MSE / Quantile — Huber CRPS
Continual Learning EWC / DER++ — — —
Fairness Group DRO — — —

📐 Key Mathematical Formulations

Cross-Entropy Loss

$$
\mathcal{L}{CE} = -\sum{c=1}^{C} y_c \log(\hat{y}_c)
$$

Binary Cross-Entropy

$$
\mathcal{L}_{BCE} = -[y \log(\hat{y}) + (1-y) \log(1-\hat{y})]
$$

Focal Loss

$$
\mathcal{L}_{FL} = -\alpha_t (1 - p_t)^\gamma \log(p_t)
$$

Dice Loss

$$
\mathcal{L}_{Dice} = 1 - \frac{2 \sum_i p_i g_i}{\sum_i p_i + \sum_i g_i}
$$

Triplet Loss

$$
\mathcal{L}_{Triplet} = \max(0, |f_a - f_p|_2 - |f_a - f_n|_2 + \alpha)
$$

InfoNCE / Contrastive Loss

$$
\mathcal{L}_{InfoNCE} = -\log \frac{\exp(\text{sim}(z_i, zj) / \tau)}{\sum{k=1}^{2N} \mathbb{1}_{[k \neq i]} \exp(\text{sim}(z_i, z_k) / \tau)}
$$

KL Divergence

$$
D_{KL}(P | Q) = \sum_x P(x) \log \frac{P(x)}{Q(x)}
$$

DDPM Loss (simplified)

$$
\mathcal{L}{DDPM} = \mathbb{E}{t, x0, \epsilon} \left[ | \epsilon - \epsilon\theta(x_t, t) |^2 \right]
$$

DPO Loss

$$
\mathcal{L}{DPO} = -\log \sigma \left( \beta \log \frac{\pi\theta(yw|x)}{\pi{ref}(yw|x)} - \beta \log \frac{\pi\theta(yl|x)}{\pi{ref}(y_l|x)} \right)
$$

IoU Loss

$$
\mathcal{L}_{IoU} = 1 - \frac{|Bp \cap B{gt}|}{|Bp \cup B{gt}|}
$$

ArcFace Loss

$$
\mathcal{L}{ArcFace} = -\log \frac{e^{s \cos(\theta{yi} + m)}}{e^{s \cos(\theta{yi} + m)} + \sum{j \neq y_i} e^{s \cos \theta_j}}
$$

Wasserstein Distance (WGAN)

$$
\mathcal{L}{WGAN} = \mathbb{E}{x \sim p{data}}[D(x)] - \mathbb{E}{z \sim p_z}[D(G(z))]
$$


Classification

0/1 Loss (1950) — The theoretical misclassification indicator; 1 if prediction ≠ label, 0 otherwise. Non-differentiable, foundational to learning theory.
📄 Statistical Decision Functions — Wald, A.

Cross-Entropy Loss / Log Loss / Negative Log-Likelihood (1948) — Measures divergence between predicted probability distribution and true labels; the default loss for multi-class classification.
📄 A Mathematical Theory of Communication — Shannon, C.E.
💻 torch.nn.CrossEntropyLoss

Binary Cross-Entropy (1958) — Cross-entropy specialized for two-class or multi-label problems; operates on each output independently.
📄 Derived from logistic regression — Cox, D.R. (1958)
💻 torch.nn.BCEWithLogitsLoss

Hinge Loss / SVM Loss (1995) — Maximizes the margin between classes; the core loss behind Support Vector Machines.
📄 Support-Vector Networks — Cortes, C. & Vapnik, V.
💻 torch.nn.MultiMarginLoss

Knowledge Distillation Loss / Soft Cross-Entropy (2015) — Trains a student network to mimic a teacher by matching softened output distributions.
📄 Distilling the Knowledge in a Neural Network — Hinton, G., Vinyals, O. & Dean, J.
💻 torch.nn.KLDivLoss

Large-Margin Softmax Loss (L-Softmax) (2016) — Introduces angular margin constraints into softmax for intra-class compactness and inter-class separability.
📄 Large-Margin Softmax Loss for Convolutional Neural Networks — Liu, W., Wen, Y., Yu, Z. & Yang, M.
💻 wy1iu/LargeMargin_Softmax_Loss

Center Loss (2016) — Penalizes distance of features from learned class centers, improving discriminative feature learning.
📄 A Discriminative Feature Learning Approach for Deep Face Recognition — Wen, Y., Zhang, K., Li, Z. & Qiao, Y.
💻 KaiyangZhou/pytorch-center-loss

Label Smoothing (2016) — Replaces hard one-hot targets with soft targets, preventing overconfident predictions and improving generalization.
📄 Rethinking the Inception Architecture for Computer Vision — Szegedy, C. et al.
💻 torch.nn.CrossEntropyLoss(label_smoothing=...)

Sparsemax Loss (2016) — Sparse alternative to softmax that assigns exactly zero probability to irrelevant classes.
📄 From Softmax to Sparsemax: A Sparse Model of Attention and Multi-Label Classification — Martins, A.F.T. & Astudillo, R.F.
💻 deep-spin/entmax

Focal Loss (2017) — Down-weights well-classified examples to focus training on hard negatives; designed for extreme class imbalance.
📄 Focal Loss for Dense Object Detection — Lin, T.-Y., Goyal, P., Girshick, R., He, K. & Dollár, P.
💻 AdeelH/pytorch-multi-class-focal-loss

Generalized Cross-Entropy (GCE) (2018) — Noise-robust loss interpolating between MAE and cross-entropy via a tunable parameter q.
📄 Generalized Cross Entropy Loss for Training Deep Neural Networks with Noisy Labels — Zhang, Z. & Sabuncu, M.R.
💻 AlanChou/Truncated-Loss

Complement Objective Training (COT) (2019) — Augments cross-entropy with a complement objective that neutralizes non-target class probabilities.
📄 Complement Objective Training — Chen, H.-Y. et al.
💻 henry8527/COT

Class-Balanced Loss (2019) — Re-weights loss by the effective number of samples per class for long-tailed distributions.
📄 Class-Balanced Loss Based on Effective Number of Samples — Cui, Y. et al.
💻 vandit15/Class-balanced-loss-pytorch

Symmetric Cross-Entropy (SCE) (2019) — Combines standard CE with reverse CE for robustness to label noise.
📄 Symmetric Cross Entropy for Robust Learning with Noisy Labels — Wang, Y. et al.

Bi-Tempered Logistic Loss (2019) — Two temperature parameters bound the loss (handling mislabeled data) and produce heavy-tailed softmax (handling outliers).
📄 Robust Bi-Tempered Logistic Loss Based on Bregman Divergences — Amid, E. et al.
💻 google/bi-tempered-loss

Taylor Cross-Entropy Loss (2020) — Taylor series expansion of CE creating a noise-robust loss.
📄 Can Cross Entropy Loss Be Robust to Label Noise? — Feng, L. et al.

Asymmetric Loss (ASL) (2021) — Different focusing levels for positive and negative samples in multi-label classification.
📄 Asymmetric Loss For Multi-Label Classification — Ben-Baruch, E. et al.
💻 Alibaba-MIIL/ASL

Poly Loss (2022) — Views loss functions as polynomial expansions and adjusts leading coefficients; generalizes CE and focal loss.
📄 PolyLoss: A Polynomial Expansion Perspective of Classification Loss Functions — Leng, Z. et al.
💻 abhuse/polyloss-pytorch

Regression

Mean Absolute Error (MAE) / L1 Loss (~1757) — Penalizes absolute differences; robust to outliers but non-smooth gradient at zero.
📄 Attributed to Boscovich, R.J. (1757)
💻 torch.nn.L1Loss

Mean Squared Error (MSE) / L2 Loss (~1805) — Penalizes squared differences; sensitive to outliers. The method of least squares.
📄 Legendre, A.-M. (1805); Gauss, C.F. (1809)
💻 torch.nn.MSELoss

Huber Loss (1964) — MSE for small errors, MAE for large errors. Robust to outliers with smooth gradients near zero.
📄 Robust Estimation of a Location Parameter — Huber, P.J.
💻 torch.nn.HuberLoss

Tukey's Biweight Loss (1974) — Redescending M-estimator that completely rejects gross outliers beyond a threshold.
📄 The Fitting of Power Series, Meaning Polynomials, Illustrated on Band-Spectroscopic Data — Beaton, A.E. & Tukey, J.W.

Quantile Loss / Pinball Loss (1978) — Asymmetrically penalizes over/under-predictions for quantile regression and uncertainty estimation.
📄 Regression Quantiles — Koenker, R. & Bassett, G.

Smooth L1 Loss (2015) — L2 for small errors, L1 for large errors (Huber with δ=1); standard for bounding box regression.
📄 Fast R-CNN — Girshick, R.
💻 torch.nn.SmoothL1Loss

Wing Loss (2018) — Amplifies small-to-medium range errors for facial landmark localization.
📄 Wing Loss for Robust Facial Landmark Localisation with Convolutional Neural Networks — Feng, Z.-H. et al.

Balanced L1 Loss (2019) — Rebalances inlier vs. outlier loss contributions in object detection regression.
📄 Libra R-CNN: Towards Balanced Learning for Object Detection — Pang, J. et al.
💻 OceanPang/Libra_R-CNN

Adaptive Wing Loss (2019) — Adapts curvature based on ground truth heatmap values for face alignment.
📄 Adaptive Wing Loss for Robust Face Alignment via Heatmap Regression — Wang, X. et al.
💻 protossw512/AdaptiveWingLoss

Log-Cosh Loss (2022) — Approximates Huber loss using log(cosh(x)); twice differentiable everywhere.
📄 Statistical Properties of the Log-Cosh Loss Function Used in Machine Learning — Chen, K. et al.

Segmentation

Sensitivity-Specificity Loss (2015) — Weighted combination of sensitivity and specificity for extreme class imbalance in lesion segmentation.
📄 Deep Convolutional Encoder Networks for Multiple Sclerosis Lesion Segmentation — Brosch et al.

Dice Loss (2016) — Directly optimizes the Dice coefficient (F1 score); robust to class imbalance.
📄 V-Net: Fully Convolutional Neural Networks for Volumetric Medical Image Segmentation — Milletari, F. et al.
💻 JunMa11/SegLossOdyssey

Generalized Dice Loss (GDL) (2017) — Per-class volume weighting for multi-class segmentation with highly imbalanced labels.
📄 Generalised Dice Overlap as a Deep Learning Loss Function for Highly Unbalanced Segmentations — Sudre, C.H. et al.

Tversky Loss (2017) — Tunable α/β parameters controlling the FP/FN trade-off; useful for small lesion segmentation.
📄 Tversky Loss Function for Image Segmentation Using 3D Fully Convolutional Deep Networks — Salehi, S.S.M. et al.

Lovász-Softmax Loss (2018) — Tractable convex surrogate for directly optimizing the Jaccard index (IoU).
📄 The Lovász-Softmax Loss: A Tractable Surrogate for the Optimization of the Intersection-Over-Union Measure — Berman, M. et al.
💻 bermanmaxim/LovaszSoftmax

Exponential Logarithmic Loss (2018) — Combines exponentially weighted focal-style Dice and CE for very small structures.
📄 3D Segmentation with Exponential Logarithmic Loss for Highly Unbalanced Object Sizes — Wong et al.

Asymmetric Similarity Loss (2018) — Asymmetric Fβ-score-based similarity to balance precision and recall.
📄 Asymmetric Loss Functions and Deep Densely Connected Networks for Highly Imbalanced Medical Image Segmentation — Hashemi et al.

Focal Tversky Loss (2019) — Focal-style exponent on Tversky loss to focus on hard, misclassified regions.
📄 A Novel Focal Tversky Loss Function with Improved Attention U-Net for Lesion Segmentation — Abraham, N. & Khan, N.M.

Boundary Loss (2019) — Distance metric on contour space rather than region overlap; effective for highly unbalanced tasks.
📄 Boundary Loss for Highly Unbalanced Segmentation — Kervadec, H. et al.
💻 LIVIAETS/boundary-loss

Hausdorff Distance Loss (2019) — Directly optimizes the Hausdorff distance between predicted and ground-truth boundaries.
📄 Reducing the Hausdorff Distance in Medical Image Segmentation with Convolutional Neural Networks — Karimi, D. & Salcudean, S.E.

Combo Loss (2019) — Weighted combination of modified CE and Dice loss for input and output class imbalance.
📄 Combo Loss: Handling Input and Output Imbalance in Multi-Organ Segmentation — Taghanaki et al.

Region Mutual Information (RMI) Loss (2019) — Maximizes mutual information between predicted and ground-truth label regions.
📄 Region Mutual Information Loss for Semantic Segmentation — Zhao et al.
💻 ZJULearning/RMI

Topological Loss (2019) — Uses persistent homology to enforce correct topological structure in segmentation.
📄 Topology-Preserving Deep Image Segmentation — Hu et al.
💻 HuXiaoling/TopoLoss

Log-Cosh Dice Loss (2020) — Log-cosh smoothing on Dice loss for smoother gradients and stable training.
📄 A Survey of Loss Functions for Semantic Segmentation — Jadon, S.

clDice (2021) — Topology-preserving loss for tubular structures; computes Dice on skeletonized centerlines.
📄 clDice — A Novel Topology-Preserving Loss Function for Tubular Structure Segmentation — Shit et al.
💻 jocpae/clDice

Unified Focal Loss (2022) — Hierarchical framework generalizing Dice-based and CE-based losses with focal modulation.
📄 Unified Focal Loss: Generalising Dice and Cross Entropy-Based Losses to Handle Class Imbalanced Medical Image Segmentation — Yeung et al.
💻 mlyg/unified-focal-loss

Object Detection (Bounding Box)

Smooth L1 Loss (2015) — Piecewise L2/L1 loss; standard for bounding box regression.
📄 Fast R-CNN — Girshick, R.

IoU Loss (2016) — Directly regresses Intersection-over-Union between predicted and ground-truth boxes.
📄 UnitBox: An Advanced Object Detection Network — Yu et al.

Focal Loss (2017) — Modulating factor (1−pₜ)^γ down-weights easy negatives in dense detection.
📄 Focal Loss for Dense Object Detection — Lin, T.-Y. et al.
💻 facebookresearch/detectron2

Bounded IoU Loss (2018) — Upper-bounds IoU change per coordinate for stable high-IoU refinement.
📄 Improving Object Localization with Fitness NMS and Bounded IoU Loss — Tychsen-Smith & Petersson

GIoU Loss (2019) — Extends IoU with a penalty based on the smallest enclosing box; enables gradient flow for non-overlapping boxes.
📄 Generalized Intersection over Union — Rezatofighi et al.

DIoU Loss (2020) — Adds normalized center-point distance penalty to IoU for faster convergence.
📄 Distance-IoU Loss: Faster and Better Learning for Bounding Box Regression — Zheng et al.
💻 Zzh-tju/DIoU

CIoU Loss (2020) — Extends DIoU with aspect ratio consistency penalty for complete geometric alignment.
📄 Distance-IoU Loss — Zheng et al.

Alpha-IoU Loss (2021) — Power parameter α amplifies loss and gradient for high-quality anchors.
📄 Alpha-IoU: A Family of Power Intersection over Union Losses — He et al.
💻 Jacobi93/Alpha-IoU

EIoU Loss (2022) — Decomposes CIoU penalty into separate width/height terms.
📄 Focal and Efficient IOU Loss for Accurate Bounding Box Regression — Zhang et al.

SIoU Loss (2022) — Angle-aware penalty considering vector direction between predicted and target boxes.
📄 SIoU Loss: More Powerful Learning for Bounding Box Regression — Gevorgyan

WIoU Loss (2023) — Dynamic non-monotonic focusing mechanism based on outlier degree.
📄 Wise-IoU: Bounding Box Regression Loss with Dynamic Focusing Mechanism — Tong et al.
💻 Instinct323/Wise-IoU

MPDIoU Loss (2023) — Bounding box similarity via minimum point distances between corners.
📄 MPDIoU: A Loss for Efficient and Accurate Bounding Box Regression — Ma & Xu

Inner-IoU Loss (2023) — IoU through auxiliary inner bounding boxes with a scaling factor.
📄 Inner-IoU: More Effective Intersection over Union Loss with Auxiliary Bounding Box — Zhang et al.

Generative Models — GANs

Minimax / Original GAN Loss (2014) — Discriminator maximizes, generator minimizes binary cross-entropy in a two-player minimax game.
📄 Generative Adversarial Nets — Goodfellow et al.

Non-Saturating GAN Loss (2014) — Generator maximizes log(D(G(z))) instead of minimizing log(1−D(G(z))), providing stronger early gradients.
📄 Generative Adversarial Nets — Goodfellow et al.

Feature Matching Loss (2016) — Generator matches expected feature statistics at an intermediate discriminator layer.
📄 Improved Techniques for Training GANs — Salimans et al.

Least Squares GAN Loss (LSGAN) (2017) — L2 objective minimizing Pearson χ² divergence for more stable training.
📄 Least Squares Generative Adversarial Networks — Mao et al.

Wasserstein Loss (WGAN) (2017) — Earth Mover's distance providing meaningful gradients even for non-overlapping distributions.
📄 Wasserstein GAN — Arjovsky, M. et al.
💻 martinarjovsky/WassersteinGAN

WGAN-GP (2017) — Gradient penalty replacing weight clipping for better Lipschitz constraint enforcement.
📄 Improved Training of Wasserstein GANs — Gulrajani et al.

Hinge Loss GAN (2017) — Max-margin formulation with bounded gradients; used in BigGAN, SAGAN.
📄 Geometric GAN — Lim & Ye
📄 Spectral Normalization for GANs — Miyato et al.

Spectral Normalization (2018) — Constrains spectral norm of weight matrices to stabilize discriminator training.
📄 Spectral Normalization for Generative Adversarial Networks — Miyato et al.

R1 Regularization (2018) — Zero-centered gradient penalty on real data for local convergence guarantees.
📄 Which Training Methods for GANs do actually Converge? — Mescheder et al.
💻 NVlabs/stylegan2-ada-pytorch

Relativistic GAN Loss (RaGAN) (2018) — Discriminator estimates probability that real data is more realistic than fake.
📄 The Relativistic Discriminator — Jolicoeur-Martineau, A.

Mode Seeking Loss (2019) — Maximizes image/latent distance ratio to encourage diverse mode exploration.
📄 Mode Seeking Generative Adversarial Networks for Diverse Image Synthesis — Mao et al.

Path Length Regularization (2020) — Consistent Jacobian norm across latent space for smooth interpolations.
📄 Analyzing and Improving the Image Quality of StyleGAN — Karras et al.
💻 NVlabs/stylegan2-ada-pytorch

LeCam Regularization (2021) — LeCam divergence-based stabilization under limited data.
📄 Regularizing Generative Adversarial Networks under Limited Data — Tseng et al.
💻 google/lecam-gan

Projected GAN Loss (2021) — Multi-scale discrimination in projected feature space from pretrained networks.
📄 Projected GANs Converge Faster — Sauer et al.

Generative Models — VAEs

ELBO / VAE Loss (2013) — Reconstruction loss + KL divergence regularizer pushing posterior toward prior.
📄 Auto-Encoding Variational Bayes — Kingma, D.P. & Welling, M.
💻 AntixK/PyTorch-VAE

β-VAE Loss (2017) — Upweights KL divergence (β > 1) for more disentangled latent representations.
📄 β-VAE: Learning Basic Visual Concepts with a Constrained Variational Framework — Higgins et al.

VQ-VAE Loss (2017) — Reconstruction + vector quantization commitment loss + codebook loss for discrete latents.
📄 Neural Discrete Representation Learning — van den Oord et al.

WAE Loss (2018) — Penalized Wasserstein distance using MMD or adversarial regularization on latent space.
📄 Wasserstein Auto-Encoders — Tolstikhin et al.

Generative Models — Diffusion & Flow

Denoising Score Matching (2011) — Training a denoising autoencoder equals matching the score function of noise-perturbed data.
📄 A Connection Between Score Matching and Denoising Autoencoders — Vincent, P.

Score Matching with Langevin Dynamics (NCSN) (2019) — Noise-conditional score network across multiple noise scales with annealed Langevin sampling.
📄 Generative Modeling by Estimating Gradients of the Data Distribution — Song, Y. & Ermon, S.

DDPM Loss (2020) — Simplified variational bound: predict the noise added at each diffusion step via weighted MSE.
📄 Denoising Diffusion Probabilistic Models — Ho, J. et al.

Variational Diffusion Loss (2021) — Continuous-time variational lower bound with learnable noise schedule.
📄 Variational Diffusion Models — Kingma et al.

v-prediction Loss (2022) — Predicts velocity v = α·ε − σ·x for improved numerical stability and progressive distillation.
📄 Progressive Distillation for Fast Sampling of Diffusion Models — Salimans, T. & Ho, J.

Rectified Flow Loss (2022) — Learns straight-line ODE trajectories between noise and data distributions.
📄 Flow Straight and Fast: Learning to Generate and Transfer Data with Rectified Flow — Liu et al.

Flow Matching Loss (2023) — Simulation-free training for continuous normalizing flows; regresses vector fields of conditional probability paths.
📄 Flow Matching for Generative Modeling — Lipman et al.
💻 facebookresearch/flow_matching

Consistency Loss (2023) — Self-consistency along the probability flow ODE for high-quality one-step generation.
📄 Consistency Models — Song et al.
💻 OpenAI/consistency_models

Reconstruction & Perceptual

SSIM Loss (2004) — Structural similarity using luminance, contrast, and structure comparisons; used as 1−SSIM.
📄 Image Quality Assessment: From Error Visibility to Structural Similarity — Wang et al.
💻 VainF/pytorch-msssim

Style Loss (Gram Matrix) (2015) — Matches Gram matrices of CNN feature maps for texture/style transfer.
📄 A Neural Algorithm of Artistic Style — Gatys et al.

Perceptual Loss / VGG Loss (2016) — L2 distance between deep feature representations of generated and target images.
📄 Perceptual Losses for Real-Time Style Transfer and Super-Resolution — Johnson et al.

LPIPS (2018) — Learned perceptual metric using calibrated deep features; correlates better with human perception than SSIM/PSNR.
📄 The Unreasonable Effectiveness of Deep Features as a Perceptual Metric — Zhang et al.
💻 richzhang/PerceptualSimilarity

Image Super-Resolution & Restoration

Charbonnier Loss (1994) — Differentiable approximation to L1 (√(x²+ε²)); robust to outliers, smooth at zero.
📄 Two Deterministic Half-Quadratic Regularization Algorithms for Computed Imaging — Charbonnier et al.

MS-SSIM Loss (2003) — Multi-scale SSIM evaluating structural similarity across multiple resolutions.
📄 Multi-Scale Structural Similarity for Image Quality Assessment — Wang et al.

SRGAN Loss (2017) — Adversarial loss + VGG perceptual content loss for photo-realistic 4× super-resolution.
📄 Photo-Realistic Single Image Super-Resolution Using a GAN — Ledig et al.

Contextual Loss (2018) — Feature-level context matching without spatial alignment; enables training with non-aligned data.
📄 The Contextual Loss for Image Transformation with Non-Aligned Data — Mechrez et al.

ESRGAN Loss (2018) — Relativistic average discriminator + pre-activation VGG perceptual loss for enhanced texture recovery.
📄 ESRGAN: Enhanced Super-Resolution Generative Adversarial Networks — Wang et al.
💻 xinntao/ESRGAN

Focal Frequency Loss (2021) — Adaptively focuses on hard-to-synthesize frequencies in the Fourier domain.
📄 Focal Frequency Loss for Image Reconstruction and Synthesis — Jiang et al.
💻 EndlessSora/focal-frequency-loss

Contrastive & Self-Supervised Learning

Contrastive Loss (2005) — Pairwise loss pulling similar pairs together and pushing dissimilar pairs apart by a margin.
📄 Learning a Similarity Metric Discriminatively, with Application to Face Verification — Chopra, Hadsell, LeCun

N-pair Loss (2016) — Generalizes triplet loss by simultaneously pushing away negatives from N−1 classes.
📄 Improved Deep Metric Learning with Multi-class N-pair Loss Objective — Sohn, K.

InfoNCE / CPC Loss (2018) — Noise-contrastive estimation maximizing mutual information between latent representations.
📄 Representation Learning with Contrastive Predictive Coding — van den Oord et al.
💻 RElbers/info-nce-pytorch

MoCo Loss (2020) — InfoNCE with momentum-updated encoder and dynamic dictionary queue.
📄 Momentum Contrast for Unsupervised Visual Representation Learning — He et al.
💻 facebookresearch/moco

NT-Xent / SimCLR Loss (2020) — Normalized temperature-scaled cross-entropy over cosine similarities of augmented pairs.
📄 A Simple Framework for Contrastive Learning of Visual Representations — Chen et al.

BYOL Loss (2020) — MSE between L2-normalized predictions and targets; learns without negative pairs via momentum teacher.
📄 Bootstrap Your Own Latent — Grill et al.

SwAV Loss (2020) — Swapped prediction contrasting cluster assignments from different augmented views.
📄 Unsupervised Learning of Visual Features by Contrasting Cluster Assignments — Caron et al.
💻 facebookresearch/swav

Supervised Contrastive Loss (SupCon) (2020) — Extends self-supervised contrastive loss with label information to pull same-class embeddings together.
📄 Supervised Contrastive Learning — Khosla et al.
💻 HobbitLong/SupContrast

Barlow Twins Loss (2021) — Cross-correlation matrix close to identity; reduces redundancy between embedding dimensions.
📄 Barlow Twins: Self-Supervised Learning via Redundancy Reduction — Zbontar et al.
💻 facebookresearch/barlowtwins

DINO Loss (2021) — Self-distillation via cross-entropy between sharpened softmax outputs of student and momentum-teacher.
📄 Emerging Properties in Self-Supervised Vision Transformers — Caron et al.
💻 facebookresearch/dino

SimSiam Loss (2021) — Negative cosine similarity with stop-gradient; no negatives, momentum, or large batches needed.
📄 Exploring Simple Siamese Representation Learning — Chen & He

CLIP Loss (2021) — Symmetric cross-entropy over image-text cosine similarities aligning visual and language representations.
📄 Learning Transferable Visual Models From Natural Language Supervision — Radford et al.
💻 mlfoundations/open_clip

VICReg Loss (2022) — Variance + invariance + covariance regularization preventing collapse without negatives.
📄 VICReg: Variance-Invariance-Covariance Regularization for Self-Supervised Learning — Bardes et al.
💻 facebookresearch/vicreg

Decoupled Contrastive Loss (2022) — Removes positive term from InfoNCE denominator, eliminating negative-positive coupling.
📄 Decoupled Contrastive Learning — Yeh et al.

DINOv2 Loss (2023) — DINO self-distillation + iBOT masked image modeling + Sinkhorn centering at scale.
📄 DINOv2: Learning Robust Visual Features without Supervision — Oquab et al.
💻 facebookresearch/dinov2

SigLIP Loss (2023) — Pairwise sigmoid loss replacing softmax for efficient batch-parallel language-image pre-training.
📄 Sigmoid Loss for Language Image Pre-Training — Zhai et al.

Metric Learning & Face Recognition

Triplet Loss (2015) — Minimizes anchor-positive distance while maximizing anchor-negative distance by a margin.
📄 FaceNet: A Unified Embedding for Face Recognition and Clustering — Schroff et al.
💻 KevinMusgrave/pytorch-metric-learning

Lifted Structured Loss (2016) — Mines all positive and negative pairs in a batch simultaneously.
📄 Deep Metric Learning via Lifted Structured Feature Embedding — Oh Song et al.

SphereFace / A-Softmax (2017) — Multiplicative angular margin on a hypersphere for discriminative face features.
📄 SphereFace: Deep Hypersphere Embedding for Face Recognition — Liu et al.

Proxy-NCA Loss (2017) — Data-to-proxy comparisons with one learnable proxy per class; dramatically faster convergence.
📄 No Fuss Distance Metric Learning Using Proxies — Movshovitz-Attias et al.

CosFace / LMCL (2018) — Cosine margin penalty on target logit in normalized softmax.
📄 CosFace: Large Margin Cosine Loss for Deep Face Recognition — Wang et al.
💻 deepinsight/insightface

ArcFace (2019) — Additive angular margin with clear geodesic distance interpretation.
📄 ArcFace: Additive Angular Margin Loss for Deep Face Recognition — Deng et al.
💻 deepinsight/insightface

Multi-Similarity Loss (2019) — Mines and weights pairs using self-similarity, relative similarity, and negative similarity.
📄 Multi-Similarity Loss with General Pair Weighting for Deep Metric Learning — Wang et al.

SoftTriple Loss (2019) — Multiple centers per class bridging proxy-based and triplet-based losses.
📄 SoftTriple Loss: Deep Metric Learning Without Triplet Sampling — Qian et al.

Circle Loss (2020) — Unified pair similarity optimization with self-paced weighting.
📄 Circle Loss: A Unified Perspective of Pair Similarity Optimization — Sun et al.

Proxy Anchor Loss (2020) — Proxies as anchors associated with all batch data; fast convergence.
📄 Proxy Anchor Loss for Deep Metric Learning — Kim et al.
💻 tjddus9597/Proxy-Anchor-CVPR2020

Sub-center ArcFace (2020) — Multiple sub-centers per class for noisy label handling.
📄 Sub-center ArcFace: Boosting Face Recognition by Large-Scale Noisy Web Faces — Deng et al.

AdaFace (2022) — Adaptive margin emphasizing hard or easy samples based on image quality.
📄 AdaFace: Quality Adaptive Margin for Face Recognition — Kim et al.
💻 mk-minchul/AdaFace

ElasticFace (2022) — Random margin values from a normal distribution each iteration for flexible separability.
📄 ElasticFace: Elastic Margin Loss for Deep Face Recognition — Boutros et al.
💻 fdbtrs/ElasticFace

NLP & Language Modeling

Cross-Entropy / Next Token Prediction — Standard autoregressive LM loss; foundation of GPT and all causal LMs.
📄 Language Models are Unsupervised Multitask Learners — Radford et al. (GPT-2, 2019)

Masked Language Model (MLM) Loss (2019) — Masks 15% of tokens and predicts from bidirectional context. Introduced pre-train/fine-tune for NLU.
📄 BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding — Devlin et al.

Replaced Token Detection (RTD) (2020) — Discriminator classifies every token as original or replaced; loss defined over all tokens for better sample efficiency.
📄 ELECTRA: Pre-training Text Encoders as Discriminators Rather Than Generators — Clark et al.

Sentence Order Prediction (SOP) (2020) — Predicts whether two consecutive segments are in correct or swapped order.
📄 ALBERT: A Lite BERT for Self-supervised Learning — Lan et al.

Span Corruption Loss (2020) — Masks contiguous spans; encoder-decoder reconstructs only missing spans. All NLP tasks as text-to-text.
📄 Exploring the Limits of Transfer Learning with a Unified Text-to-Text Transformer — Raffel et al.

Mixture of Denoisers (MoD) (2022) — Unifies causal LM, prefix LM, and span corruption into a single pre-training objective.
📄 UL2: Unifying Language Learning Paradigms — Tay et al.

LLM Alignment (RLHF / DPO)

PPO Loss / RLHF (2017/2022) — Clipped surrogate objective for aligning LLMs with human preferences via a learned reward model.
📄 Proximal Policy Optimization Algorithms — Schulman et al.
📄 Training language models to follow instructions with human feedback — Ouyang et al.
💻 huggingface/trl

Reward Model Loss / Bradley-Terry (2022) — Cross-entropy on pairwise human preferences for training scalar reward models.
📄 Training language models to follow instructions with human feedback — Ouyang et al.

SLiC-HF Loss (2023) — Contrastive ranking loss calibrating sequence likelihoods to human preferences.
📄 SLiC-HF: Sequence Likelihood Calibration with Human Feedback — Zhao et al.

DPO Loss (2023) — Closed-form policy optimization directly from preference pairs; no separate reward model or RL loop.
📄 Direct Preference Optimization: Your Language Model is Secretly a Reward Model — Rafailov et al.
💻 huggingface/trl — DPOTrainer

IPO Loss (2023) — Squared loss on preference margins avoiding overfitting to Bradley-Terry assumption.
📄 A General Theoretical Paradigm to Understand Learning from Human Preferences — Azar et al.

CPO Loss (2024) — Contrastive preference loss without reference model for machine translation.
📄 Contrastive Preference Optimization — Xu et al.

KTO Loss (2024) — Kahneman-Tversky prospect theory applied to alignment; works from binary (good/bad) feedback.
📄 KTO: Model Alignment as Prospect Theoretic Optimization — Ethayarajh et al.
💻 huggingface/trl — KTOTrainer

GRPO Loss (2024) — Group Relative Policy Optimization; estimates advantages from sampled output groups, eliminating the critic model.
📄 DeepSeekMath: Pushing the Limits of Mathematical Reasoning in Open Language Models — Shao et al.

ORPO Loss (2024) — Odds-ratio penalty added to SFT loss; combines instruction tuning and preference alignment in one stage.
📄 ORPO: Monolithic Preference Optimization without Reference Model — Hong et al.
💻 huggingface/trl — ORPOTrainer

SimPO Loss (2024) — Reference-free preference optimization using length-normalized average log probability as implicit reward.
📄 SimPO: Simple Preference Optimization with a Reference-Free Reward — Meng et al.
💻 princeton-nlp/SimPO

SPPO Loss (2024) — Self-play preference optimization framing alignment as a two-player constant-sum game.
📄 Self-Play Preference Optimization for Language Model Alignment — Wu et al.

Sequence-to-Sequence & Speech

CTC Loss (2006) — Marginalizes over all valid alignments between input and output sequences; foundational for ASR.
📄 Connectionist Temporal Classification — Graves et al.
💻 torch.nn.CTCLoss

RNN-T Loss (2012) — Extends CTC with a prediction network conditioning on previous outputs for streaming transduction.
📄 Sequence Transduction with Recurrent Neural Networks — Graves, A.
💻 torchaudio.transforms.RNNTLoss

Scheduled Sampling Loss (2015) — Gradually replaces ground-truth tokens with model predictions during training to mitigate exposure bias.
📄 Scheduled Sampling for Sequence Prediction with Recurrent Neural Networks — Bengio et al.

Sequence-Level Training / MIXER (2016) — Directly optimizes BLEU/ROUGE using REINFORCE.
📄 Sequence Level Training with Recurrent Neural Networks — Ranzato et al.

Minimum Risk Training (2016) — Minimizes expected task-level loss (e.g., 1−BLEU) via sampling.
📄 Minimum Risk Training for Neural Machine Translation — Shen et al.

Mel-Spectrogram Reconstruction Loss (2017) — L1/L2 between predicted and target mel-spectrograms; primary TTS training objective.
📄 Tacotron: Towards End-to-End Speech Synthesis — Wang et al.

Multi-Resolution STFT Loss (2020) — Spectral convergence + log-magnitude STFT at multiple FFT sizes for neural vocoder training.
📄 Parallel WaveGAN — Yamamoto et al.
💻 csteinmetz1/auraloss

Reinforcement Learning

TD Loss / Temporal Difference (1988) — Bootstrapped value estimation updating predictions toward reward + discounted next-state value.
📄 Learning to Predict by the Methods of Temporal Differences — Sutton, R.S.

Q-Learning Loss (1989) — Off-policy TD control bootstrapping with max Q-value over next actions.
📄 Learning from Delayed Rewards — Watkins, C.J.C.H.

REINFORCE / Policy Gradient (1992) — Monte Carlo policy gradient weighted by returns.
📄 Simple Statistical Gradient-Following Algorithms for Connectionist Reinforcement Learning — Williams, R.J.

DQN Loss (2015) — Q-learning with deep networks, experience replay, and target networks.
📄 Human-level Control through Deep Reinforcement Learning — Mnih et al.
💻 DLR-RM/stable-baselines3

Double DQN Loss (2015) — Decouples action selection from evaluation to reduce overestimation bias.
📄 Deep Reinforcement Learning with Double Q-learning — van Hasselt et al.

DDPG Loss (2015) — Deterministic policy gradients for continuous control with experience replay.
📄 Continuous Control with Deep Reinforcement Learning — Lillicrap et al.

GAE (2015) — Exponentially-weighted multi-step TD errors for tunable bias-variance tradeoff.
📄 High-Dimensional Continuous Control Using Generalized Advantage Estimation — Schulman et al.

A3C / A2C Loss (2016) — Actor-critic with policy gradient + value function baseline + entropy bonus.
📄 Asynchronous Methods for Deep Reinforcement Learning — Mnih et al.

Distributional RL / C51 Loss (2017) — Models full return distribution using categorical projection over fixed atoms.
📄 A Distributional Perspective on Reinforcement Learning — Bellemare et al.

PPO Clipped Surrogate Loss (2017) — Clips probability ratio to prevent destructively large policy updates.
📄 Proximal Policy Optimization Algorithms — Schulman et al.
💻 DLR-RM/stable-baselines3

HER Loss (2017) — Relabels failed trajectories with achieved goals for sample-efficient sparse-reward learning.
📄 Hindsight Experience Replay — Andrychowicz et al.

QR-DQN Loss (2018) — Quantile regression approximating the return distribution with learnable quantile locations.
📄 Distributional Reinforcement Learning with Quantile Regression — Dabney et al.

SAC Loss (2018) — Maximum entropy actor-critic balancing exploration and exploitation automatically.
📄 Soft Actor-Critic — Haarnoja et al.

TD3 Loss (2018) — Clipped double-Q learning + delayed policy updates + target policy smoothing.
📄 Addressing Function Approximation Error in Actor-Critic Methods — Fujimoto et al.

V-trace Loss (2018) — Importance-weighted off-policy correction for scalable distributed RL (IMPALA).
📄 IMPALA: Scalable Distributed Deep-RL — Espeholt et al.

Decision Transformer Loss (2021) — RL as sequence modeling; autoregressive transformer conditioned on returns, trained with supervised loss.
📄 Decision Transformer: Reinforcement Learning via Sequence Modeling — Chen et al.
💻 kzl/decision-transformer

Knowledge Distillation

Knowledge Distillation / KD Loss (2015) — Student matches softened output distribution of teacher via KL divergence at elevated temperature.
📄 Distilling the Knowledge in a Neural Network — Hinton, Vinyals, Dean

FitNets / Hint Loss (2015) — Student mimics intermediate feature representations of teacher.
📄 FitNets: Hints for Thin Deep Nets — Romero et al.

Attention Transfer Loss (2017) — Forces student to mimic spatial attention maps of teacher's intermediate layers.
📄 Paying More Attention to Attention — Zagoruyko & Komodakis
💻 szagoruyko/attention-transfer

Born-Again Networks (2018) — Self-distillation where identical-architecture student outperforms teacher.
📄 Born Again Neural Networks — Furlanello et al.

PKT / Probabilistic KD (2018) — Matches probability distributions in feature space rather than raw representations.
📄 Learning Deep Representations with Probabilistic Knowledge Transfer — Passalis & Tefas

Relational KD / RKD (2019) — Transfers mutual relations (distances and angles) between examples.
📄 Relational Knowledge Distillation — Park et al.

Self-Distillation Loss (2019) — Deeper layers supervise shallower classifiers within the same network.
📄 Be Your Own Teacher — Zhang et al.

CRD / Contrastive Representation Distillation (2020) — Maximizes mutual information between teacher and student via contrastive objective.
📄 Contrastive Representation Distillation — Tian et al.
💻 HobbitLong/RepDistiller

ReviewKD (2021) — Student's lower-level features guided by teacher's higher-level features through attention-based fusion.
📄 Distilling Knowledge via Knowledge Review — Chen et al.
💻 dvlab-research/ReviewKD

DKD / Decoupled KD (2022) — Decouples KD into target-class and non-target-class components for independent weighting.
📄 Decoupled Knowledge Distillation — Zhao et al.
💻 megvii-research/mdistiller

DIST Loss (2022) — Preserves inter-class relations and intra-class ranking rather than exact probability matching.
📄 Knowledge Distillation from A Stronger Teacher — Huang et al.
💻 hunto/DIST_KD

Regularization

KL Divergence (1951) — Measures information lost when approximating one distribution with another.
📄 On Information and Sufficiency — Kullback & Leibler

L2 Regularization / Weight Decay (1970) — Penalizes sum of squared weights to prevent overfitting.
📄 Ridge Regression — Hoerl & Kennard

L1 Regularization / Lasso (1996) — Penalizes sum of absolute weights, inducing sparsity.
📄 Regression Shrinkage and Selection via the Lasso — Tibshirani, R.

Elastic Net (2005) — Combines L1 and L2 for sparsity + grouping of correlated features.
📄 Regularization and Variable Selection via the Elastic Net — Zou & Hastie

Dropout (2014) — Randomly zeroes activations; implicit ensemble of exponentially many sub-networks.
📄 Dropout: A Simple Way to Prevent Neural Networks from Overfitting — Srivastava et al.

Confidence Penalty (2017) — Penalizes low-entropy (overconfident) output distributions.
📄 Regularizing Neural Networks by Penalizing Confident Output Distributions — Pereyra et al.

Mixup Loss (2018) — Trains on convex combinations of example pairs and their labels.
📄 mixup: Beyond Empirical Risk Minimization — Zhang et al.
💻 facebookresearch/mixup-cifar10

Manifold Mixup (2019) — Extends Mixup to hidden representations at random intermediate layers.
📄 Manifold Mixup: Better Representations by Interpolating Hidden States — Verma et al.

CutMix Loss (2019) — Cuts and pastes rectangular patches between images while mixing labels proportionally.
📄 CutMix: Regularization Strategy to Train Strong Classifiers with Localizable Features — Yun et al.

3D Vision & Point Clouds

Chamfer Distance (2017) — Average nearest-neighbor distance between two point sets; fast and widely used.
📄 A Point Set Generation Network for 3D Object Reconstruction from a Single Image — Fan et al.
💻 facebookresearch/pytorch3d

Earth Mover's Distance (EMD) (2017) — Optimal transport distance with bijective matching; higher quality but more expensive than CD.
📄 A Point Set Generation Network for 3D Object Reconstruction from a Single Image — Fan et al.

Normal Consistency Loss (2018) — Penalizes inconsistency of surface normals between adjacent mesh faces.
📄 Pixel2Mesh: Generating 3D Mesh Models from Single RGB Images — Wang et al.

Mesh Laplacian Smoothing Loss (2018) — Penalizes vertex deviation from neighbor centroid to prevent self-intersections.
📄 Pixel2Mesh — Wang et al.
💻 facebookresearch/pytorch3d

SDF Loss (DeepSDF) (2019) — Regresses signed distance values; zero level-set defines the 3D surface.
📄 DeepSDF: Learning Continuous Signed Distance Functions for Shape Representation — Park et al.
💻 facebookresearch/DeepSDF

Occupancy Loss (2019) — Binary CE on predicted occupancy probabilities for 3D reconstruction.
📄 Occupancy Networks: Learning 3D Reconstruction in Function Space — Mescheder et al.

NeRF Photometric Loss (2020) — MSE between rendered and observed pixel colors via differentiable volume rendering.
📄 NeRF: Representing Scenes as Neural Radiance Fields for View Synthesis — Mildenhall et al.

3D Gaussian Splatting Loss (2023) — L1 + D-SSIM for optimizing anisotropic 3D Gaussians for real-time radiance field rendering.
📄 3D Gaussian Splatting for Real-Time Radiance Field Rendering — Kerbl et al.
💻 graphdeco-inria/gaussian-splatting

Depth Estimation

Scale-Invariant Loss (2014) — Log-space depth error minus mean shift; invariant to global scale ambiguity.
📄 Depth Map Prediction from a Single Image using a Multi-Scale Deep Network — Eigen et al.

Berhu Loss (Reverse Huber) (2016) — L1 for small residuals, L2 for large; robust depth regression.
📄 Deeper Depth Prediction with Fully Convolutional Residual Networks — Laina et al.

Photometric Consistency Loss (2017) — Self-supervised SSIM + L1 with left-right disparity consistency for monocular depth.
📄 Unsupervised Monocular Depth Estimation with Left-Right Consistency — Godard et al.
💻 nianticlabs/monodepth2

Edge-Aware Smoothness Loss (2017) — Locally smooth depth except at image edges, weighted by image gradients.
📄 Unsupervised Monocular Depth Estimation with Left-Right Consistency — Godard et al.

Medical Imaging

Deep Supervision Loss (2015) — Auxiliary losses at intermediate layers providing direct gradient paths.
📄 Deeply-Supervised Nets — Lee et al.

Dice Loss (2016) — Directly optimizes Dice coefficient for volumetric medical image segmentation.
📄 V-Net — Milletari et al.

Generalized Dice Loss (2017) — Per-class volume weighting for highly imbalanced multi-class segmentation.
📄 Generalised Dice Overlap as a Deep Learning Loss Function — Sudre et al.

Tversky Loss (2017) — Tunable FP/FN trade-off for small lesion segmentation.
📄 Tversky Loss Function for Image Segmentation — Salehi et al.

Attention-Gated Loss (2018) — Learned attention gates suppress irrelevant regions in skip connections.
📄 Attention U-Net: Learning Where to Look for the Pancreas — Oktay et al.

Boundary / Surface Loss (2019) — Distance metric on contour space for highly unbalanced medical segmentation.
📄 Boundary Loss for Highly Unbalanced Segmentation — Kervadec et al.
💻 LIVIAETS/boundary-loss

Distance Map Penalized CE (2019) — Weights CE by distance transform maps to focus on boundary regions.
📄 Distance Map Loss Penalty Term for Semantic Segmentation — Caliva et al.

Graph Neural Networks

Variational Graph Auto-Encoder (VGAE) Loss (2016) — Reconstruction BCE on adjacency matrix + KL divergence for unsupervised graph learning.
📄 Variational Graph Auto-Encoders — Kipf & Welling

Node Classification Loss (2017) — Standard cross-entropy per-node in semi-supervised graph settings.
📄 Semi-Supervised Classification with Graph Convolutional Networks — Kipf & Welling
💻 pyg-team/pytorch_geometric

Deep Graph Infomax (DGI) Loss (2019) — Maximizes mutual information between local node and global graph representations.
📄 Deep Graph Infomax — Veličković et al.
💻 PetarV-/DGI

Graph Matching Loss (2019) — Attention-based cross-graph matching with margin-based pairwise loss.
📄 Graph Matching Networks for Learning the Similarity of Graph Structured Objects — Li et al.

InfoGraph Loss (2020) — Maximizes mutual information between graph-level and substructure-level representations.
📄 InfoGraph: Unsupervised and Semi-supervised Graph-Level Representation Learning — Sun et al.
💻 sunfanyunn/InfoGraph

GraphCL Loss (2020) — NT-Xent contrastive loss on augmented graph views for self-supervised graph learning.
📄 Graph Contrastive Learning with Augmentations — You et al.
💻 Shen-Lab/GraphCL

BGRL Loss (2022) — Negative-sample-free self-supervised loss bootstrapping graph representations (inspired by BYOL).
📄 Large-Scale Representation Learning on Graphs via Bootstrapping — Thakoor et al.
💻 nerdslab/bgrl

Recommendation Systems

ListNet Loss (2007) — Listwise learning-to-rank using top-one probability distributions.
📄 [Learning to Rank: From Pairwise Approach to Listwise Approach](https://www.microsoft.com/en-us/research/wp-content/uploads/2016/0