Turning Stale Gradients into Stable Gradients: Coherent Coordinate Descent with Implicit Landscape Smoothing for Lightweight Zeroth-Order Optimization
Researchers propose Coherent Coordinate Descent (CoCD), a deterministic zeroth-order optimization method that improves sample efficiency for scenarios where backpropagation is unavailable. The approach reframes stale gradients as computational assets and demonstrates that larger finite-difference step sizes create implicit landscape smoothing, achieving superior convergence stability compared to existing randomized methods across neural network architectures.