2019/04/11 by Danczul, Tobias, Schöberl, Joachim
#26C15 (Secondary) #35J15 (Primary) 65N25 #35P10 #46B70 #65N12 #65N15 #65N30 #FOS: Mathematics #Numerical Analysis (math.NA)
paper · doi:10.48550/arxiv.1904.05599
We propose and analyze new numerical methods to evaluate fractional norms and apply fractional powers of elliptic operators. By means of a reduced basis method, we project to a small dimensional subspace where explicit diagonalization via the eigensystem is feasible. The method relies on several independent evaluations of (\textrmI-ti2Δ)-1f, which can be computed in parallel. We prove exponential convergence rates for the optimal choice of sampling points ti, provided by the so-called Zolotarëv points. Numerical experiments confirm the analysis and demonstrate the efficiency of our algorithm.