The components that define a partial differential equation problem are: the partial differential equation, the domain, and boundary conditions. In //ELLPACK there is an equation and a domain editor which allow you to specify each of these components.
The equation editor is shown at the left of the session window. This editor allows you to enter the PDE equation that will be solved. It uses MAXIMA as it's symbolic language processor. An experienced MAXIMA user can use the equation tool's interface to MAXIMA to manipulate equations. Other functionality that this editor provides are specifying the forcing solution, linearizing PDEs, specifying initial guesses, and generating a default ELLPACK program.
The two-dimensional domain builder is to the right of the session window in the figure above. Here you define the domain on which the PDE equation will be solved. The domain is defined by a boundary and any subsequent holes removed from the boundary. //ELLPACK defines a boundary as a parameterized piecewise-linear curve. The outer boundary should always be defined in a clockwise manner and holes should be defined in a counter-clockwise manner. The domain editor also allows boundary conditions to be specified on each piece of each boundary of the domain.
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