For: Instructions for my C++ Elliptic PDE Solver Programs using Mixed
Methods on General Geometrices.  P.T. Keenan.


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This manual describes the four elliptic solver programs
\verb+elliptic_m2d_X+, where X is the name of the numerical method
used in that variant. The four programs are otherwise identical and
build on a substantial C++ library of tools for general geometry and
linear algebra. The four methods are defined in detail in "Mixed
Finite Element Methods as Finite Difference Methods for Solving
Elliptic Equations on Triangular Elements", by T. Arbogast, C. Dawson,
and P. T. Keenan. In particular, X is \verb+saddlepoint+ for the MFEM,
\verb+hybrid+ for the MHFEM, \verb+stencil+ for the CCSM, and
\verb+enhanced+ for the ECCSM. These C++ programs all solve the
elliptic partial differential equation

$$ -\nabla\cdot(K\nabla p) = f, $$ 

on some two dimensional polygonal region $\Omega$ defined by triangles
and rectangles, where $K$ is a symmetric tensor function of position.
All the programs can handle general domain shapes, which are specified
in an input file by means of a simple geometry description language.