"Application Of Fast Poisson Solvers To The Numerical Approzimation Of " by Billy Lewis Buzbee

Publication Date

7-6-1972

Abstract

Let T be a positive constant, let D^n be the interior of the unit hypercube in R^n with boundary ∂D^n, let a(t;x1,x2,…,xn) be a strictly positive funtion, and consider the parabolic problem ut= ∇*a ∇u + s(t;x1,x2,…,xn) in D^nx[0,T]

Where

U(t)=0 on ∂D^nx[0,T]

And

U(0)=f

This report compares three A-stable marching procedures for approximating this problem by finite differences. The procedures considered are the pure explicit procedure (APX) with 6t sufficiently restricted to insure A-stability, the pure implicit procedure (PM) or backwards difference equation, and a recently developed pure implicit procedure (SOC) which is second order correct in time and space. The implementation of PM and SOC in D^n requires the solution of large linear systems at each time step, and fast Poisson solvers provide efficient techniques for solving similar systems. Thus we show that the Buneman Poisson solver can be “truncated” when it is applied to PM with a(t;x1,x2,…,xn)=costant.

Degree Name

Mathematics

Level of Degree

Doctoral

Department Name

Mathematics & Statistics

First Committee Member (Chair)

Alfred Samuel Carasso

Second Committee Member

Reuben Hersh

Third Committee Member

George Milton Wing

Language

English

Document Type

Dissertation

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