KO: Kinetics-inspired Neural Optimizer with PDE Simulation Approaches
Mingquan Feng, Yixin Huang, Yifan Fu, Shaobo Wang, Junchi Yan

TL;DR
KO is a physics-inspired neural optimizer that models training dynamics as a particle system governed by PDEs, promoting parameter diversity and outperforming traditional optimizers in various tasks.
Contribution
The paper introduces KO, a novel optimizer based on kinetic theory and PDE simulation, offering a physics-driven approach to improve neural network training.
Findings
KO outperforms Adam and SGD on image and text classification tasks.
KO maintains parameter diversity, reducing parameter collapse.
Experimental results show accuracy improvements with comparable computational cost.
Abstract
The design of optimization algorithms for neural networks remains a critical challenge, with most existing methods relying on heuristic adaptations of gradient-based approaches. This paper introduces KO (Kinetics-inspired Optimizer), a novel neural optimizer inspired by kinetic theory and partial differential equation (PDE) simulations. We reimagine the training dynamics of network parameters as the evolution of a particle system governed by kinetic principles, where parameter updates are simulated via a numerical scheme for the Boltzmann transport equation (BTE) that models stochastic particle collisions. This physics-driven approach inherently promotes parameter diversity during optimization, mitigating the phenomenon of parameter condensation, i.e. collapse of network parameters into low-dimensional subspaces, through mechanisms analogous to thermal diffusion in physical systems. We…
Peer Reviews
Decision·Submitted to ICLR 2026
1. The collision-inspired mechanism is conceptually interesting and plausibly bridges ideas from kinetic theory to practical optimization. 2. The paper includes both proofs and experiments, which helps substantiate the method’s validity.
There are shortcomings in the manuscript’s writing standards and in the completeness of the experiments. See the following questions.
1. The idea of using particle collision dynamics to reduce weight condensation is interesting and might be impactful. 2. Since the idea only modifies the gradients, it could be used with existing optimizers. 3. The results on classification tasks show marginal but consistent improvements on both validation accuracy and weight condensation.
1. The method is proposed as a way to reduce neuron condensation; however, the modification is only applied to the gradients and not the updated weights. This is important as weights are initialized randomly, so they are all different, and just using gradient similarity to modify them does not make sense to me. Please clarify this. 2. Weight condensation and neuron condensation are used interchangeably; however, they might mean different things. Please clarify. Also, please clarify how cosine si
- The paper introduces a new training method that adjusts the gradients during updates, using ideas inspired from physics - particle collisions. The method is quite agnostic to the rest of the training process and can be employed in many training frameworks and optimizers. - Numerically, the results are very convincing in improving the performance of other optimizers. - Theory justifies these results - reducing the layer weight correlation. - Computationally the method is not heavy.
- In terms of comparisons, I would have expected that the authors compare more clearly with regularization based approaches. In the introduction, the latter are described as post-hoc, but I am not convinced about this. In principle, regularization addresses the same issue, poor generalization. - Convergence is proven, but it is not clear what is the impact of the proposed approach. I expect that the introduced 'collisions' cause the gradient directions to change randomly, and as a result, creat
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Taxonomy
TopicsNeural Networks and Applications
MethodsDiffusion · Adam
