changelog

TOYFDTD1 is a stripped-down minimalist, 3D FDTD code demonstrating the basic tasks in implementing a

changelog file for ToyFDTD1 

1 December, 1999  Laurie E. Miller  [e-mail]

	* ToyFDTD1-v1.03.  Updating contact and web information.  Also note
	the name has changed from ToyFDTD to ToyFDTD1.  ToyFDTD is now the 
	name of this family of codes: ToyFDTD1, ToyFDTD2, ToyFDTD3...

	* Tarball contains ToyFDTD1.c, ToyFDTD1.f90, README, Makefile, 
	chengGbry.cmap, changelog, gpl.txt
	
12 August, 1999  Laurie E. Miller  [e-mail]
	
	* ToyFDTD-1.02.  Addition of F90 source code, and some tweaks to the C.
	
	* Tarball contains ToyFDTD.c, ToyFDTD.f90, README, Makefile, 
	chengGbry.cmap, changelog, gpl.txt

	* Changes to C source code from version 1.0: The changes here are not
 	huge, consisting of: 
	1. Corrections to bloopers resulting from sleep 
	   deprivation, and 
	2. Tweaks that help the C and FORTRAN versions to be as identical
	   as possible.  Here is a listing of the changes to the C code: 

	* There is some change in the naming convention of the files, since
 	there are now C and FORTRAN versions of the 3D code.

	* The URLs and email addresses have changed, though the old ones 
        will still work just fine.

	* The global constants ONE, TWO, etc. have been removed -- archaic 
        holdover on my part.  The constant TWENTY_FIVE is now called
        CELLS_PER_WAVELENGTH, since that's what it's used for.  

	* The global constants MU_0, EPSILON_0, and PI have been defined
        explicitly.  That way, you know what you're getting, and the C
        and FORTRAN versions will match.

	* The variables dtmu and dteps are no longer defined since they are
        not used for anything.  

	* Previously, the 3D scaled output was scaled not from 0 to 255, as 
	the comments said, but from -1 to 255.  On all the volume visualization
        tools I've worked with, the -1 is simply wrapped to the 255 value
        which can be a nice feature since it shows you precisely where the
        most negative value is.  However, it might cause problems on tools
        I haven't worked with, so now the output is scaled from 0 through
        254.  This gives an equal range of values above and below 127,
        which is held to be data zero.  The colormap that is included in the 
        tar file with this code still goes from 0 to 255, but 254 and 255 are 
        assigned the same rgb values.  

	* Making sure that the last data computed gets output is handled
        differently.  In the 1.0 code the comments said that you should set 
        MAXIMUM_ITERATION to some integer multiple of 
        PLOT_MODULUS plus one.  The plus one should have been left off
        -- this would be one of those sleep-deprivation things.  ;>  In this 
        code the last timestep is output whether it's an integer multiple of
        PLOT_MODULUS or not, so you just need to remember the last
        3D output file may come after an interval shorter than the interval
        separating previous output files.  

	* The input stimulus is modified slightly.  Both the 1.0 stimulus 
	function and the 1.02 stimulus function produce a somewhat aphysical
        approximation to a plane wave insertion at one end of the mesh.
        And both produce animations that look the same using the type
        of scaled 3D output implemented here.   But which is closer to truly
        physical depends on what physical setup you imagine you're using
        for inserting the stimulus into the guide.  I changed it because the 
        1.02 version of the stimulus is probably closer to what most people
        are thinking of when they imagine a simplified plane wave inserted
        from the end of the mesh.  

	* "Source" now refers to the C or FORTRAN source code, and "stimulus"
        refers to the input waveform of the simulation.  Previously both
        were referred to as "source".  OK, so that's nitpicky, but I'm trying
 	to be helpful.  :)
	

12 April, 1999  Laurie E. Miller  [e-mail]
	
	* First release. 
	
	* Tarball contains ToyFDTD.c, README, Makefile, chengGbry.cmap