Abstract:The FETI-DP domain decomposition method (DDM) is extended to address the iterative solution of a class of indefinite problems of the form (A − σM)x = b, where A and M are two real symmetric positive semi-definite matrices arising from the finite element discretization of second-order elastodynamic problems, and σ is a positive number. A key component of this extension is a new coarse problem based on the free-space solutions of Navier's homogeneous displacement equations of motion. These solutions are waves, a… Show more
“…Cai and Widlund [5; 6; 7] studied overlapping Schwarz methods for such problems, using a perturbation approach in their analysis, and established that the convergence rates of the two-level overlapping Schwarz methods are independent of the mesh size if the coarse mesh is fine enough. Motivated by the FETI-DPH method proposed by Farhat and Li [16] for solving symmetric indefinite problems, the authors [23] studied a BDDC algorithm for solving Helmholtz equations and estimated its convergence rate using a similar perturbation approach. For some other results using the perturbation approach for domain decomposition methods, see [40; 38; 19].…”
The balancing domain decomposition methods by constraints are extended to solving nonsymmetric, positive definite linear systems resulting from the finite element discretization of advection-diffusion equations. A preconditioned GM-RES iteration is used to solve a Schur complement system of equations for the subdomain interface variables. In the preconditioning step of each iteration, a partially subassembled interface problem is solved. A convergence rate estimate for the GMRES iteration is established for the cases where the advection is not strong, under the condition that the mesh size is small enough. The estimate deteriorates with a decrease of the viscosity and for fixed viscosity it is independent of the number of subdomains and depends only slightly on the subdomain problem size. Numerical experiments for several two-dimensional advectiondiffusion problems illustrate the fast convergence of the proposed algorithm for both diffusion-dominated and advection-dominated cases.
“…Cai and Widlund [5; 6; 7] studied overlapping Schwarz methods for such problems, using a perturbation approach in their analysis, and established that the convergence rates of the two-level overlapping Schwarz methods are independent of the mesh size if the coarse mesh is fine enough. Motivated by the FETI-DPH method proposed by Farhat and Li [16] for solving symmetric indefinite problems, the authors [23] studied a BDDC algorithm for solving Helmholtz equations and estimated its convergence rate using a similar perturbation approach. For some other results using the perturbation approach for domain decomposition methods, see [40; 38; 19].…”
The balancing domain decomposition methods by constraints are extended to solving nonsymmetric, positive definite linear systems resulting from the finite element discretization of advection-diffusion equations. A preconditioned GM-RES iteration is used to solve a Schur complement system of equations for the subdomain interface variables. In the preconditioning step of each iteration, a partially subassembled interface problem is solved. A convergence rate estimate for the GMRES iteration is established for the cases where the advection is not strong, under the condition that the mesh size is small enough. The estimate deteriorates with a decrease of the viscosity and for fixed viscosity it is independent of the number of subdomains and depends only slightly on the subdomain problem size. Numerical experiments for several two-dimensional advectiondiffusion problems illustrate the fast convergence of the proposed algorithm for both diffusion-dominated and advection-dominated cases.
“…Solving these problems by the FETI-DP method requires first transforming them into the interface problems (for example, see [8][9][10][11][12][13])…”
Section: Acceleration Of Convergence For Problems With Multiple Rightmentioning
confidence: 99%
“…In this paper, the scalable domain decomposition (DD)-based finite element tearing and interconnecting dual-primal (FETI-DP) method [8][9][10][11][12][13], which is an enhanced variant of the ubiquitous iterative FETI solver [10,[14][15][16][17][18][19][20][21][22][23][24][25][26][27], is proposed as an incomplete block-diagonal preconditioning solver for Equation (1). It is equipped with the Krylov reusage technique first proposed in [15,16] for accelerating its convergence for systems with multiple and repeated right-hand sides.…”
SUMMARYIn the spectral stochastic finite element method for analyzing an uncertain system, the uncertainty is represented by a set of random variables, and a quantity of interest such as the system response is considered as a function of these random variables. Consequently, the underlying Galerkin projection yields a block system of deterministic equations where the blocks are sparse but coupled. The solution of this algebraic system of equations becomes rapidly challenging when the size of the physical system and/or the level of uncertainty is increased. This paper addresses this challenge by presenting a preconditioned conjugate gradient method for such block systems where the preconditioning step is based on the dual-primal finite element tearing and interconnecting method equipped with a Krylov subspace reusage technique for accelerating the iterative solution of systems with multiple and repeated right-hand sides. Preliminary performance results on a Linux Cluster suggest that the proposed solution method is numerically scalable and demonstrate its potential for making the uncertainty quantification of realistic systems tractable.
“…Domain decomposition methods have been proposed for Helmholtz problems in [7,8,9,10,11,12], and for elastic problems in [13,14,15,16]. Controllability methods have been proposed for both Helmholtz and Navier problems in [17,18].…”
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