Title

Eigenvalue bounds for Laplacian

Author

xfliu

Description

The explicit lower bound and upper bound for the Laplace differential operator are obtained by using the conforming and non-conforming finite element method.

Properties

Public

  • README
  • DIRECTORY
  • DEMO

Bounding eigenvalue for the Laplacian by using the finite element method

Abstract of the project

This project shows how to apply the conforming and non-conforming FEMs to obtain explicit lower and upper bounds for the eigenvalues of the Laplacian.

Code structure

There are two cases of numerical computation. In each case folder, there are pre-prepared meshes.

  • Unit square domain. The eigenvalue problem on this domain has a closed-form expression and the estimated eigenvalue bounds are compared with the exact ones directly.
  • L-shaped domain. For this domain, there is no closed-form expression for the eigenvalues and there are eigenfunctions missing the $H^2$-regularity. For this case, the conforming FEM and the Crouzeix-Raviart FEM are used to obtain upper and lower bounds, respectively.

How to run the code

Open file EigenvalueBounds.ipynb and run the cells.

Last updated: August 8, 2024

About the directory

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