This distribution contains code which implements the "perfect"total-field/scattered-field boundary condition as described in apaper submitted to the IEEE Transactions on Antennas andPropagation.  You should read that paper before using this code(even though that paper provides no explanation of how to use thiscode).The code assumes a two-dimensional computational domain with TMzpolarization (i.e., non-zero field Ez, Hx, and Hy).  The program iscurrently written so that the incident field always strikes thelower-left corner of the total-field region first.  (If you want adifferent corner, that should be a fairly simple tweak to the code,but for now you'll have to make that tweak yourself.)  I haveattempted to provide copious comments in the code and hope that aknowledgeable C programmer can quickly map the approach as describedin the paper to what is in the program.The following files are provided:  ptfsf.c   -- heart of the perfect TFSF code  ptfsf.h   -- header file for same  ptfsf-demo.c -- FDTD code which demonstrates use of perfect TFSF code.                       essentially this program used to generate                       results shown in the paper (output written for                       four observations points)  ptfsf-file-maker.c -- code to generate an incident-field file                       using the "perfect" incident fields  ptfsf-demo-file.c  -- FDTD code which uses the perfect incident                       fields stored in a file  fdtdgen.h -- defines macros used in much of my code  Makefile  -- simple makefile to compile programs.  this make file                       should work on "reasonable" UNIX-based systems                       with the GNU compiler installed (known to work                       on a Mac running OS X 10.3).  You may add the                       -DTIMING directive if you want timing output.  README    -- this file  runit-demo   -- script to run the demo with reasonable input  runit-file-gen -- script to run file maker with reasonable input  runit-file-use -- script to use previously generated incident-field fileThere is no reason you would have to use these scripts.  The programsare designed to be run interactively, but the scripts are there ifwant them.  Edit them for you particular needs.You must have the FFTw routines installed to use the code aswritten.  See www.fftw.org for details.  Alternatively, you couldmodify the code and use your own FFT's, but I would discourage that.If you have questions, comments, suggestions, or especiallyimprovements or bug fixes, please let me know!  However, please keepin mind that this code is provided "as is" and I may not be able toincorporate edits, make modifications, or fully address any questionsyou have.Enjoy,  John Schneider  January, 2004  schneidj@eecs.wsu.edu