You enter points graphically and then the program draws a smooth 
curve through them, a uniform cubic spline. v1.1 for TI-82.



    SPLINE is Freeware
    Commercial Distribution Restricted
    Copyright (C) 1994 by Mikael Bonnier, Lund, Sweden.


1. System and Memory Requirements
This program is for the TI-82. It consists of one main program,
that uses 1078 bytes. It requires an additional 635 bytes for data
to execute (for 5 vertices).

SPLINE alters these variables:
Real:   A,B,C,D,E,F,G,H,I,K,L,M,N,S,T,V,W,X,Y
List:   L1,L2,L3,L4
Y-Vars: Y1,Y2,Y3,Y4,Y5,Y6,Y0,X1t,Y1t,X2t,Y2t (deleted by SPLINE)


2. Installation
If you have TI-GRAPH LINK UUDecode this file, and send the resulting
SPLINE.82P program to the calculator. If you don't have the 
link you will have to enter the ASCII82P listing below.

The reason why the UUE portion of this file in v1.0 didn't work was
because of bugs in ASCII82P.EXE, this was cured by editing the program
on a Macintosh. The ASCII82P listing was correct though.


4. User Instructions
Start the program by entering: prgmSPLINE
You will be prompted for the number of vertices (or nodes, or 
points). Begin with say eight (max 99).

Move the cross-hairs using the arrow keys and press enter. The 
cross-hairs returns to the origin. Repeat this for the remaining
vertices.

Wait while the program calculates the slope at each vertice.
Then watch how the program plots the spline (uniform cubic).
The program then pauses, press enter to continue.

Now you can enter the frequency, that is the number of 
subintervals the curve divided into, one less than the number of 
strokes. The frequency is 100 initially. You can also quit here by 
entering 0. 

You can view the data lists using [STAT] 1 (Edit...), X and Y
coordinates in L1 and L2, and the X slope and Y slope in L3 and L4.
You can write a simple program to view the slope at each vertice:
:For(I,1,dim L1)
:Line(L1(I),L2(I),L1(I)+.1L3(I),L2(I)+.1L4(I))
:End


5. References      
If you are not hooked by the special offer below you can always 
check out these:

A. K. Dewdney.
"The (New) Turing Omnibus".
Computer Science Press and W. H. Freeman and Company, New York, 1993.

William H. Press, Brian P. Flannery, Saul A. Teukolsky, and William 
T. Vetterling.
"Numerical Recipes: The Art of Scientific Computing".
Cambridge University Press, Cambridge, 1986.

Bruce A. Artwick.
"Microcomputer Displays, Graphics, and Animation".
Prentice-Hall, Englewood Cliffs, N.J., 1985.


6. Special Offer (for Internet users only)
If you want I can send you a clearly written explanation of the 
SPLINE program and the special techniques I used when I developed it.
You get this by sending me US$10 to the address below. This offer 
expires in August 1994. This explanation will be sent to you only via
internet e-mail, so you must include your internet address with your
order.


Money, suggestions, bug and bad-English-in-doc reports
are always welcome to:
                 Mikael Bonnier
                 Osten Undens gata 88
                 S-227 62  LUND
                 SWEDEN
                             
Or use my internet address:
                 mikaelb@df.lth.se

// Mikael Bonnier
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