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Sampling from Non-Log-Concave Distributions via Variance-Reduced Gradient Langevin Dynamics
Proceedings of the Twenty-Second International Conference on Artificial Intelligence and Statistics, PMLR 89:2936-2945, 2019.
Abstract
We study stochastic variance reduction-based Langevin dynamic algorithms, SVRG-LD and SAGA-LD \citep{dubey2016variance}, for sampling from non-log-concave distributions. Under certain assumptions on the log density function, we establish the convergence guarantees of SVRG-LD and SAGA-LD in 2-Wasserstein distance. More specifically, we show that both SVRG-LD and SAGA-LD require ˜O(n+n3/4/ϵ2+n1/2/ϵ4)⋅exp(˜O(d+γ)) stochastic gradient evaluations to achieve ϵ-accuracy in 2-Wasserstein distance, which outperforms the ˜O(n/ϵ4)⋅exp(˜O(d+γ)) gradient complexity achieved by Langevin Monte Carlo Method \citep{raginsky2017non}. Experiments on synthetic data and real data back up our theory.