Stochastic interior-point methods for smooth conic optimization with applications
Chuan He, Zhanwang Deng
TL;DR
The paper develops a general stochastic interior-point framework for smooth conic optimization, addressing problems of the form $\min_x f(x)$ s.t. $Ax=b$ and $x\in\mathcal{K}$ with accessible stochastic gradients. It introduces four SIPM variants—mini-batch estimators, Polyak momentum, extrapolated Polyak momentum, and recursive momentum—and proves iteration complexities matching the best known stochastic unconstrained results up to polylog factors: $\tilde{O}(\epsilon^{-2})$, $\tilde{O}(\epsilon^{-4})$, $\tilde{O}(\epsilon^{-7/2})$, and $\tilde{O}(\epsilon^{-3})$ respectively. The analysis relies on a logarithmically homogeneous self-concordant barrier, local-norm Lipschitz properties, and barrier-based approximate optimality, yielding convergence to an $\epsilon$-stochastic stationary point under mild assumptions. Numerical experiments on robust linear regression, multi-task relationship learning, and clustering data streams demonstrate the practical effectiveness and efficiency of SIPMs, achieving competitive or superior performance compared with full-batch IPMs and specialized baselines. This framework enables scalable, theory-grounded conic optimization in ML with large datasets and general conic constraints.
Abstract
Conic optimization plays a crucial role in many machine learning (ML) problems. However, practical algorithms for conic constrained ML problems with large datasets are often limited to specific use cases, as stochastic algorithms for general conic optimization remain underdeveloped. To fill this gap, we introduce a stochastic interior-point method (SIPM) framework for general conic optimization, along with four novel SIPM variants leveraging distinct stochastic gradient estimators. Under mild assumptions, we establish the iteration complexity of our proposed SIPMs, which, up to a polylogarithmic factor, match the best-known {results} in stochastic unconstrained optimization. Finally, our numerical experiments on robust linear regression, multi-task relationship learning, and clustering data streams demonstrate the effectiveness and efficiency of our approach.
