AI & ML Efficiency Breakthrough

Enables model adaptation on edge devices and non-differentiable (quantized) models using a purely backpropagation-free optimization framework.

March 17, 2026

Original Paper

ZOTTA: Test-Time Adaptation with Gradient-Free Zeroth-Order Optimization

Ronghao Zhang, Shuaicheng Niu, Qi Deng, Yanjie Dong, Jian Chen, Runhao Zeng

arXiv · 2603.14254

The Takeaway

Existing test-time adaptation (TTA) requires high-memory backpropagation, which is often impossible on edge hardware or with hard-quantized weights. ZOTTA uses Zeroth-Order Optimization with automated layer selection to achieve adaptation performance comparable to BP-based methods using only forward passes.

From the abstract

Test-time adaptation (TTA) aims to improve model robustness under distribution shifts by adapting to unlabeled test data, but most existing methods rely on backpropagation (BP), which is computationally costly and incompatible with non-differentiable models such as quantized models, limiting practical deployment on numerous edge devices. Recent BP-free approaches alleviate overhead but remain either architecture-specific or limited in optimization capacity to handle high-dimensional models. We p