SPICE: Scaling-Aware Prediction Correction Methods with a Free Convergence Rate for Nonlinear Convex Optimization

Abstract: Recently, the prediction-correction method has been developed to solve nonlinear convex optimization problems. However, its convergence rate is often poor since large regularization parameters are set to ensure convergence conditions. In this paper, the scaling-aware prediction correction (\textsf{Spice}) method is proposed to achieve a free convergence rate. This method adopts a novel scaling technique that adjusts the weight of the objective and constraint functions. The theoretical analysis demonstrates that increasing the scaling factor for the objective function or decreasing the scaling factor for constraint functions significantly enhances the convergence rate of the prediction correction method. In addition, the \textsf{Spice} method is further extended to solve separable variable nonlinear convex optimization. By employing different scaling factors as functions of the iterations, the \textsf{Spice} method achieves convergence rates of $\mathcal{O}(1/(t+1))$, $\mathcal{O}(1/[e^{t}(t+1)])$, and $\mathcal{O}(1/(t+1)^{t+1})$. Numerical experiments further validate the theoretical findings, demonstrating the effectiveness of the \textsf{Spice} method in practice.