Background for Elliptic Equations
As examples of
elliptic partial differential equations,
we consider the
Laplace equation,
Poisson equation,
and
Helmholtz equation.
Recall that the Laplacian of the functionu(x,y)is
.
With this notation, we can write the Laplace, Poisson, and Helmholtz
equations in the following forms:
It is often the case that the boundary values for the functionu(x,y)are
known at all points on the sides of a rectangular regionRin
the plane. In this case, each of these equations can be solved by the numerical
technique known as the finite-difference method.
Program Dirichlet Method for Laplace's equation)
To approximate the solution of the Laplace's equation
over
the rectangle
with
,
,for
,and
,for
.It
is assumed that
and
integersnandmexist so that
.
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