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Error Estimates for Generalized Barycentric Interpolation
Andrew Gillette1, Alexander Rand, Chandrajit Bajaj
1Department of Mathematics, University of Texas at Austin, agillette@math.utexas.edu.
This study analyzes three finite element methods for polygonal domains, finding optimal convergence estimates are achievable under specific geometric conditions for Wachspress, Sibson, and Harmonic interpolants.
Area of Science:
- Numerical Analysis
- Computational Geometry
- Finite Element Methods
Background:
- Finite element methods (FEM) rely on accurate interpolants for convergence.
- Generalizing interpolants beyond triangles to polygonal domains is a key challenge.
- Barycentric interpolation functions offer a foundation for such generalizations.
Purpose of the Study:
- To establish optimal convergence estimates for first-order interpolants in FEM for convex planar polygonal domains.
- To compare three distinct approaches: Wachspress, Sibson, and Harmonic.
- To identify geometric conditions influencing the convergence of these interpolants.
Main Methods:
- Investigated Wachspress rational functions for interpolation.
- Analyzed Sibson interpolants utilizing Voronoi diagrams.
- Examined Harmonic interpolants derived from partial differential equations (PDEs).
- Evaluated convergence properties based on polygon geometric characteristics.
Main Results:
- All three methods (Wachspress, Sibson, Harmonic) can achieve optimal convergence estimates.
- The optimal convergence depends on specific geometric conditions of the polygon.
- The maximum interior angle condition, crucial for triangles, is necessary for Wachspress functions but not for Sibson functions.
Conclusions:
- The choice of interpolation method impacts convergence requirements for polygonal domains.
- Sibson interpolants offer greater flexibility regarding polygon geometry compared to Wachspress.
- These findings advance the development of robust finite element methods for complex geometries.
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