2021/09/06 by Sanz-Alonso, Daniel, Yang, Ruiyi · 2 citations
#Computation (stat.CO) #FOS: Computer and information sciences #FOS: Mathematics #Numerical Analysis (math.NA)
paper · doi:10.48550/arxiv.2109.02777
The stochastic partial differential equation approach to Gaussian processes (GPs) represents Matérn GP priors in terms of n finite element basis functions and Gaussian coefficients with sparse precision matrix. Such representations enhance the scalability of GP regression and classification to datasets of large size N by setting n≈ N and exploiting sparsity. In this paper we reconsider the standard choice n ≈ N through an analysis of the estimation performance. Our theory implies that, under certain smoothness assumptions, one can reduce the computation and memory cost without hindering the estimation accuracy by setting n ≪ N in the large N asymptotics. Numerical experiments illustrate the applicability of our theory and the effect of the prior lengthscale in the pre-asymptotic regime.