2020/07/21 by Aku Kammonen, Jonas Kiessling, Kammonen, Aku +7 · 3 citations
Computer Science · Mathematics · #65C05 (Secondary) #65D15 (Primary) 65D40 #FOS: Mathematics #Numerical Analysis (math.NA) #cs.NA #math.NA #msc:65C05 #msc:65D15 #msc:65D40
paper · pdf · doi:10.48550/arxiv.2007.10683
arxiv created 2020/11/26 · arxiv updated 2020/11/30
The supervised learning problem to determine a neural network approximation ℝd\ni x↦∑k=1Kβk eiωk⋅ x with one hidden layer is studied as a random Fourier features algorithm. The Fourier features, i.e., the frequencies ωk∈ℝd, are sampled using an adaptive Metropolis sampler. The Metropolis test accepts proposal frequencies ωk', having corresponding amplitudes βk', with the probability min\1, (|βk'|/|βk|)γ\, for a certain positive parameter γ, determined by minimizing the approximation error for given computational work. This adaptive, non-parametric stochastic method leads asymptotically, as K→∞, to equidistributed amplitudes |βk|, analogous to deterministic adaptive algorithms for differential equations. The equidistributed amplitudes are shown to asymptotically correspond to the optimal density for independent samples in random Fourier features methods. Numerical evidence is provided in order to demonstrate the approximation properties and efficiency of the proposed algorithm. The algorithm is tested both on synthetic data and a real-world high-dimensional benchmark.