Abstract

Abstract We propose a multi-level type operator that can be used in the framework of operator (or Caldéron) preconditioning to construct uniform preconditioners for negative order operators discretized by piecewise polynomials on a family of possibly locally refined partitions. The cost of applying this multi-level operator scales linearly in the number of mesh cells. Therefore, it provides a uniform preconditioner that can be applied in linear complexity when used within the preconditioning framework from our earlier work [Uniform preconditioners for problems of negative order, Math. Comp. 89 (2020), 645–674].

Highlights

  • In this work, we construct a multi-level type preconditioner for operators of negative orders −2s ∈ [−2, 0] that can be applied in linear time and yields uniformly bounded condition numbers

  • We propose a multi-level type operator that can be used in the framework of operator preconditioning to construct uniform preconditioners for negative order operators discretized by piecewise polynomials on a family of possibly locally refined partitions

  • It provides a uniform preconditioner that can be applied in linear complexity when used within the preconditioning framework from our earlier work [Uniform preconditioners for problems of negative order, Math

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Summary

Introduction

We construct a multi-level type preconditioner for operators of negative orders −2s ∈ [−2, 0] that can be applied in linear time and yields uniformly bounded condition numbers. We construct a suitable multi-level type operator BST that can be applied in linear complexity. For this construction, we require T to be a family of conforming partitions created by newest vertex bisection [7, 13]. In the aforementioned setting of having an arbitrary s ∈ [0, 1], this multi-level operator BST induces a uniform preconditioner GT, i.e., GT AT is uniformly well-conditioned, where the cost of applying GT scales linearly in dim VT.

Outline
Notation
Preconditioning
Construction of Optimal Preconditioners
Implementation of GT
Piecewise Constant Trial Space VT
Higher Order Case
An Operator BST of Multi-level Type
Definition and Analysis of BST
Implementation of BST
Manifold Case
Numerical Experiments
Uniform Refinements
Local Refinements
Full Text
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