arXiv Machine Learning

AdamNX: An Adam improvement algorithm based on a novel exponential decay mechanism for the second-order moment estimate

arXiv:2511. 13465v5 Announce Type: replace Abstract: This paper studies the exponential decay mechanism of the second-moment estimate in Adam.

arXiv Machine Learning
Sep 11

AdamX: Cosine similarity meets gradient descent

AdamX is a new first‑order optimizer that uses cosine similarity to adaptively control update magnitudes, making it scalable, model‑agnostic, and easy to add to existing training pipelines. It also includes a variance rectification scheme that smooths optimization early in training. Empirical results show AdamX achieves competitive convergence rates across various benchmark datasets and architectures, measured by the number of epochs needed to hit predefined performance thresholds under a fixed hyperparameter budget.

By Francisco Caldas, Ruben Belo, Cl\'audia Soares
arXiv Machine Learning
1d ago

How Far is Adam from Natural Gradient Descent?

The paper investigates how Adam’s update rule relates to natural gradient descent (NGD) by treating Adam as a diagonal empirical Fisher approximation with additional factors such as diagonal truncation, empirical label substitution, and temporal lag. Using a scale‑invariant metric, the authors quantify Adam’s geometric deviation from true NGD across four loss landscapes—well‑conditioned and ill‑conditioned linear regression, logistic regression, and a small neural network—finding that deviation is low in well‑conditioned settings but can reach about 10³ in ill‑conditioned or non‑convex scenarios. Despite higher geometric drift correlating with slower early optimization, Adam still achieves low final loss, and the improved empirical Fisher (iEF) yields more stable trajectories than the standard empirical Fisher (EF).

By Vihaan Paka-Hegde
arXiv Machine Learning
Aug 18

Adaptive Optimization via Momentum on Variance-Normalized Gradients

arXiv:2602. 10204v2 Announce Type: replace Abstract: We introduce MVN-Grad (Momentum on Variance-Normalized Gradients), an Adam-style optimizer that improves stability and performance by combining two complementary ideas: variance-based normalization and momentum applied after normalization.

By Francisco Patitucci, Aryan Mokhtari
arXiv Machine Learning
Sep 2

Uniform a priori bounds and error analysis for the Adam stochastic gradient descent optimization method

The paper establishes uniform a priori bounds for the Adam optimizer, enabling an unconditional error analysis for a broad class of strongly convex stochastic optimization problems. Prior analyses were conditional, assuming Adam remained bounded, whereas this work removes that assumption. The results provide a rigorous foundation for Adam’s performance in training deep neural networks and other convex optimization tasks.

By Steffen Dereich, Thang Do, Arnulf Jentzen
arXiv AI
Sep 18

Why $\beta_1 = \beta_2$ Is Dynamically Special in Adam

The paper investigates why setting the two momentum parameters of Adam equal (β1=β2) has a special dynamic effect. By analysing Adam in continuous time, the authors show that the update decomposes into a sign component, a magnitude‑lag term proportional to the difference between the two memory times, and other terms. This lag term disappears exactly when β1=β2, making the diagonal the only regime where the mismatch‑induced response is structurally absent. Experiments on six vision and language tasks confirm that tied configurations are sign‑dominated, have smaller lag contributions, and exhibit smoother update‑norm trajectories.

By Alberto Fern\'andez-Hern\'andez, Cristian P\'erez-Corral, Jose I. Mestre, Manuel F. Dolz, Enrique S. Quintana-Ort\'i
arXiv Machine Learning
Jun 15

Beyond a Single Explanation of the Adam--SGD Gap

arXiv:2606. 14259v1 Announce Type: new Abstract: Prior work has identified several factors that can contribute to the performance gap between Adam and SGD, spanning data aspects, architecture design, and optimization properties.

By Chenxiang Zhang, Rustem Islamov, Enea Monzio Compagnoni, Jun Pang, Aurelien Lucchi, Antonio Orvieto