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Smoothers for Matrix-Free Algebraic Multigrid Preconditioning of High-Order Finite Elements

Technical Report ·
DOI:https://doi.org/10.2172/1660522· OSTI ID:1660522
 [1];  [2];  [2]
  1. California Institute of Technology (CalTech), Pasadena, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

We investigate smoothers for use in matrix-free algebraic multigrid (AMG) preconditioning of high-order finite element problems. These AMG preconditioners are matrix-free in the sense that they are built from a related low-order refined finite element problem whose system matrix can be much more rapidly assembled than the high-order problem. Our proposed smoother, which we call distributive relaxation, is more robust to the anisotropy present in many low-order refined meshes which feature a clustering of nodes near the boundaries between high-order finite elements. For solving the low-order refined problem, we show that this new distributive relaxation smoother possesses significantly improved performance compared to more traditional smoothers.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); California Institute of Technology (CalTech), Pasadena, CA (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
DOE Contract Number:
AC52-07NA27344
OSTI ID:
1660522
Report Number(s):
LLNL-TR-814531; 1023036
Country of Publication:
United States
Language:
English