This is a program to simulate temperature distribution of a
thin plate, the thin plate is thermally isolated in the way
that heat can not flow through the two faces parellel to the
screen, there is neither heat source nor sink in the plate
and heat can only flow in and out through the four edges of
the thin plate.

Immediately after we put a thin plate of a certain initial
temperature into an envornement which fixes the temperatures
of the four edges of the thin plate to some values, the
temperatures within the thin plate shall change spatially
and temporally. Finally the temperatures shall reach a
steady-state condition when they no longer change in terms
of time and space. 

This program shows the temperature distribution in
equilibrium condition and a very special case how the
equilibrium condition is reached in terms of time and space.

Features of the program


There are five temperature sliders to enable users to set
four fixed edge temperatures and one initial plate

lefttemp	Left edge temperature
toptemp		Top edge temperature
rightte		Right edge temperature
bottomt		Bottom edge temperature
inplate		Initial plate temperature

There is one slider used to set the length of the thin
plate, the number of the slider is the percentage of the
thin plate of the screen-size.

scale		Percentage of plate to screen-size

The last slider is used together with man-go button, it
varies the speed to reach equilibrium condition and the
resulotion of the result:

step		Increment size


There are three buttons with the following functions:

setup		Initializing all conditions
auto-go		To execute automatically
man-go		To execute manually
show-heat-flow	To show heat flow lines
hide-heat-flow	To hide heat flow lines after
		"show-heat-flow" button is pressed


Three monitors are used to give user some important

timer		A clock
maxvariation	The maximum temperature variation of all
		patches for the latest two calculations
temp-at 0 0	The temperature at the center, a rule is 
		that the value of it should be the average 
		of the four edge temperatures, this gives 
		users a rough idea on how close the condition 
		is to the steady-state condition.



	1. Set the five temperatures by temperature sliders;
	2. Set the size of the plate by the scale slider;
	3. Press "setup" button and then "man-go" button and
	   adjust "step" slider to speed up or slow down the 
	   simulation process;
	4. Press "man-go" button to stop simulation process
	   whenever desired results are got;
	5. Press "show-heat-flow" button to see heat flow lines.


	1. Set the five temperatures by temperature sliders;
	2. Set the size of the plate by the scale slider;	
	3. Press "setup" button and then "auto-go" button;
	4. Press "auto-go" button to stop simualtion whenever
	   desired results are got;
	5. Press "show-heat-flow" button to show heat flow lines.

	1. The equilibrium temperature distribution for different
	   edge temperature settings.
	2. The process how the equilibrium is reached.


There are three units used in this simulation, time,
temperature and length, users are supposed to keep track of
the units they input and calibrations can be made to show
real units with similirity rules.


   1		100		0		0		0
   2		0		100		100		100
   3		0		33		66		99
   4		25		0		25		100

To avoid singularity and infinite loop, please do not set
all the five temperatures at one single value.


Now, the model this program simulates is the most
typical classic problem with a square thin plate being the
most common shape, and the boundary conditions are the
simplest. When users are familier with this model, they can
try some more complex ones in terms of shape and boundary
conditions, such as rectangular, circle, ovel and any shape
other than primative shapes mentioned above, as boundary
conditions are concerned, they can try derivative and
combined conditions.