Title
FAST SOLUTION OF FULLY IMPLICIT RUNGE--KUTTA AND DISCONTINUOUS GALERKIN IN TIME FOR NUMERICAL PDEs, PART I: THE LINEAR SETTING
Abstract
Fully implicit Runge--Kutta (IRK) methods have many desirable properties as time integration schemes in terms of accuracy and stability, but high-order IRK methods are not commonly used in practice with numerical PDEs due to the difficulty of solving the stage equations. This paper introduces a theoretical and algorithmic preconditioning framework for solving the systems of equations that arise from IRK methods applied to linear numerical PDEs (without algebraic constraints). This framework also naturally applies to discontinuous Galerkin discretizations in time. Under quite general assumptions on the spatial discretization that yield stable time integration, the preconditioned operator is proven to have condition number bounded by a small, order-one constant, independent of the spatial mesh and time-step size, and with only weak dependence on number of stages/polynomial order; for example, the preconditioned operator for 10th-order Gauss IRK has condition number less than two, independent of the spatial discretization and time step. The new method can be used with arbitrary existing preconditioners for backward Euler-type time-stepping schemes and is amenable to the use of three-term recursion Krylov methods when the underlying spatial discretization is symmetric. The new method is demonstrated to be effective on various high -order finite-difference and finite element discretizations of linear parabolic and hyperbolic problems, demonstrating fast, scalable solution of up to 10th-order accuracy. The new method consistently outperforms existing block preconditioning approaches, and in several cases, the new method can achieve 4th-order accuracy using Gauss integration with roughly half the number of preconditioner applications and wallclock time as required using standard diagonally IRK methods.
Year
DOI
Venue
2022
10.1137/21M1389742
SIAM JOURNAL ON SCIENTIFIC COMPUTING
Keywords
DocType
Volume
Runge-Kutta, implicit, precondition, PDEs
Journal
44
Issue
ISSN
Citations 
1
1064-8275
0
PageRank 
References 
Authors
0.34
0
4
Name
Order
Citations
PageRank
Ben S. Southworth100.34
Oliver Krzysik200.34
Will Pazner341.90
Hans De Sterck420426.14