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1990-10-10
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Plotter V3.71
© by Rüdiger Dreier 1988/9/90
Plotter is FREEWARE.
THE AUTHOR UNDERTAKES NO LIABILITY FOR ANY DAMAGE CAUSED BY THE
APPROPRIATE OR NOT APPROPRIATE USE OF THIS PROGRAM !
THE AUTHOR UNDERTAKES NO LIABILITY FOR THE FAULTLESSNESS OF THIS
PROGRAM !
USE IT AT YOUR OWN RISK !
The Plotter is a little program to plot twodimensional functions. You
can enter up to 10 functions and plot them all. In addition, you can
plot the first and second differentiation of the functions (numerical
and symbolic).
What you need:
- An Amiga with at least 512kB (more is better)
- Kickstart 1.2 or 1.3
- A stack of at least 20000
- in LIBS: - mathieeedoubbas.library
- mathieeedoubtrans.library
- tool.library (should be also on this disk)
The menus:
C-Plot
Precision
You get a submenu with three items (low, med and high). If you
select med or high, the program needs more time to plot and the plot
becomes better.
Intervall
Here you can enter the intervall, the function is plotted for. You
are asked for x-min, x-max, y-min and y-max.
Clear
The screen is cleared. This is also done after intervall.
Print
Prints the screen on your preferences printer (as big as possible).
Zoom
You get a rubberbanding and can select the part of the intervall
which will be plottet next. Using the big screen (see below) you can
scroll through the screen using the cursour-keys and ESC.
Const
Here you can enter values for the constants a, b, c and d.
About
You get some pice of information about this program. Click in the
window to close it.
QUIT
A requester appears and asks you whether to quit or not.
Function
Change
A submenu with the ten functions appears (only the first 14
characters are displayed). Here you can select one of the functions
and change it (A window appears). The function can consist of
()+-*/^, sin, cos, tan, log, int, sgn, abs, sqr, asin, acos, atan,
ln and the constants a, b, c and d and the variable x. e (2.7...)
and pi (3.14...) are already set. Numbers must be in a usual format
(1; 1.1; .1; 3e5; 5d-7...). All characters must be lower case
!!!!!!!!
Valid function:
sin(x^2)
cos(x^-2)*tan(x+2+3+4)
x^(2+345)
If you enter something like sin((x), the window appears again as
long as there is one bracket too much.
Funcion, 1st/2nd Diff num/symb
Each of this five items has the same submenu as Change. Selecting
one of the functions plots it (or its 1st or 2nd differentiation).
Numerical differentiations are calculated using the secant method.
Symbolic differentiations are calculated first and then the new
function is plotted (e.g. for sin(x): first cos(x) is calculated as
the differentiation of sin(x) and then it is plotted).
Symbolic differentiations are more precise but there are problems
with some function (abs, sgn, ln). E.g. for ln you get the function
1/x plotted even for negativ x.
When an error was found during plotting (division by zero for
example) a requester appears with the message "There was an error".
To stop plotting, click in the window. A requester appears and you
can select whether to continue or stop.
Discussion
Here you can get some pice of information about the function:
The intervall is displayed as well as the first and second
differentiation. Also the points where the function is zero, has a
min or max or a turning point.
For some functions, the differentiation is not correct for all
values. The following differentiations are used:
+-*/ : The usual ones
x^a : a*x^(a-1)
a^x : a^x*ln(a)
f(x)^g(x) : (g(x)*ln(f(x)))'*f(x)^g(x)
(Do you know a better solution ?)
trigonometr. functionen : The usual ones
abs(x) : sgn(x) (for x=0 not correct)
int(x) : 0 (Well.....)
sgn(x) : 0 (Well.....)
So for abs(x^3) you get 3*x^2*sgn(x^3). That's correct for all x<>0.
THE AUTHOR UNDERTAKES NO LIABILITY FOR THE CORRECTNESS OF THE
DIFFERENTIATION !!
Dimens.
Here you can select whether you want to have only a 640x200 screen
or a 1000x300 superbitmap-screen. If you select the big-screen, you
can scroll through it with the cursour keys and ESC (return to the
upper left corner).
Some more things:
At the end of BerechnungsRoutinen.c are two stub-routines used for the
Lattice-Compiler. Users of any other compiler may delete this lines.
Known bugs:
- The value of a function is sometimes calculated to zero (even when
it is not). This bug is not reproducible.
- Sometimes I get a TrapV-exeption. Also not reproducible.
If you have hints, questions (please add postage for the answer),
bug-reports (wrong differentiation) or money for me, here is my
address:
Rüdiger Dreier
Gustav-Winkler Str. 40
D-4800 Bielefeld 18
West Germany
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