                           Description of Files

* ellCoaxMesh.m: Meshing for the cross section of a coaxial cable
                 with elliptic conductors.
* rectMesh.m:    Meshing for a rectangle.

                These are mesh generation routines.
                The return values are:
                        [elems, nodes, fvIdx, pvIdx, pvals]

                        elems: Each row of this nElems x 3
                               matrix contains the node numbers
                               of a triangle. The node location for
                               node "k" will be in the k-th row
                               of the "nodes" matrix. 
                        nodes: nNodes x 2 matrix. Each row contains
                               the x coordinate first and then the
                               y coordinate of a node.

                        fvIdx: one dimensional array of node numbers
                               at which the potential is free to vary,
                               that is not prescribed.

                        pvIdx: one dimensional array of node numbers
                               at which the potential is prescribed.

                        pvals: One dimensional array of prescribed
                               potentials. The k-th entry of this
                               array is the potential prescribed at
                               the node number given by the k-th
                               entry of the pvIdx array. For most
                               example problems a prescribed value
                               is either a 0 or a 1.

* findST.m
           Given the elems and the nodes array this routine computes
           the S and T matrices. See my notes in fem.pdf file for the
           meaning of these two matrices. For solving the Laplace equation
           only the S matrix is needed.


* findUW.m
           Solves for the potential array U, and stored energy U'SU/2.

* ldemo.m
           Demo for the solution of the 2D Laplace equation in a rectangle
           in which three walls are at potential 0 and one wall is at
           potential 1. (This is usually the first problem discussed
           in demonstrating the method of "separation of variables".)

* ellCaps.m
           Used for finding the capacitance per unit length (normalized
           to epsilon_0) of a cable with elliptical conductors.

* meshplot.m
           Generates a Postscript file showing the meshing.

* writeSurface.m
           Generates a file suitable for viewing by "glsurf.exe".
           

* glsurf.c: A program for surface plotting using OpenGL, downloaded
            from a software repository. I did not write this.
* Makefile: Makefile for maintaining glsurf.exe

Note: When these examples were written, Octave (a free software replacement
for MATLAB) did not have very good surface plotting facilities. So I used
glsurf. I believe today Octave has very good surface plotting routines.
