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Directors:
Randolph E. Bank
Philip E. Gill
Michael Holst

Terry Le

Office: AP&M 7431
Phone: (858)534-9813
Fax: (858)534-5273
E-mail: tele@ucsd.edu
A two-grid finite element method for semilinear PDEs with interface

Yunrong Zhu
UCSD

Abstract:

In this talk, we consider solving semilinear PDEs with discontinuous diffusion coefficients by a two-grid algorithm. The algorithm consists of a coarse solver on the original nonlinear problem, and a single linear Newton update. Under the assumption that the nonlinear function is monotone, we derive the a priori $L^{\infty}$ bounds of the continuous solution, and $L^{\infty}$ bounds on the discrete solutions with additional angle condition on the triangulation. With the help of these a priori $L^{\infty}$ bounds, we derive quasi-optimal error estimate. We also derive the $L^2$ error estimate via duality argument. Finally, we give the error estimate on the numerical solution generated by the two-grid algorithm. Numerical results justify our theoretical conclusions.

Tuesday, October 4, 2011
11:00AM AP&M 2402