Inexact IETI-DP for Conforming Isogeometric Multi-Patch Discretizations

Abstract

In this paper, we investigate Dual-Primal Isogeometric Tearing and Interconnecting (IETI-DP) methods for conforming Galerkin discretizations on multi-patch computational domains with inexact subdomain solvers. Recently, the authors have proven a condition number estimate for a IETI-DP solver that is explicit, among other parameters, in the grid size and the spline degree. The analysis assumes that the local subproblems are solved exactly, e.g., using a direct solver. In the present paper, we change the method in order to allow inexact solvers for the local subproblems, namely solvers based on the fast diagonalization method. This gives a faster overall solver, maintaining the same explicit condition number bound.