(Get your freeware here - we're dealin'!)
The following educational programs are available here.
None is claimed as an example of excellence in programming,
nor should they be used for any serious purpose other
than the fun of learning. Enjoy!
Partial Differential Equation solvers
These programs are intended for beginning students of PDE's,
say sophomore engineering students.
No prior knowledge required. Point, click,
and learn. The object is to develop some feeling for what
these equations are about. You'll like these. Trust me.
They are called Heat Equation 1D, Heat Equation 2D,
Wave Equation 1D, and Wave Equation 2D.
The originals were Macintosh programs:
(265kBytes)
PDE Programs
Now available: java versions 
Also source code
for these applets.
Ordinary Differential Equation solvers
There are two de solvers, for systems of up to 3 first order
differential equations. They are handy but not sophisticated,
using the fourth order Runge-Kutta method. One is a java applet,
and one is an equivalent unix-style C program. The java applet
is educational and easy to use, and the C program is fast.
There is also a java applet which solves the forced pendulum
equation x''+(1/q)x'+sin(x) = g cos(wt).
- DE:
- run java applet de
- download C source code
here
for de
- download java source code
here
for de
- Both sources contain equation parsers in their
respective languages, which you might need independently of any
interest in differential equations.
- The C parser source also contains a small handy scientific
calculator using a text interface rather than graphics, which allows
user-defined functions. If you just want that executable, here are a few:
scalc.exe for dos or windows,
scalc.lin for linux,
scalc.sol for solaris (why not?)
- Pendulum:
- run
Pendulum applet
- download java source
here
for the Pendulum applet.
Miscellaneous programs
- scalc
- A small scientific calculator which allows you to define your
own functions. See above under DE.
- map applet
- A java applet in which you can experiment with mappings of the
plane. It isn't set up for iteration, but rather for
seeing the image of sets you draw in the domain.
- run the map applet
- linear algebra applet:
-
A java applet which allows you to
experiment with 2 by 2 matrices
as linear transformations. Try it out!
- run the linear transformation applet
- View the source code.
Mac3D Art:
Make your own stereograms! The scene may be specified
using either a grayscale picture, a function defined in the plane,
or parametric equations of a space curve. The sea (self-extracting archive)
contains the program as well as an article explaining how stereograms
work. (140 kBytes)
download Mac3D Art for Macintosh
- RO: a Roman numeral translator
- I know you won't believe this, but ro is a fairly
popular program, judging from comments received.
- Information about RO
- download RO.EXE for dos
- Roman Numerals for Macintosh
- view C source code for ro
- PT: Polynomial Teacher, a tiny numeric and symbolic
algebra program
- Factor your polynomials here! Intended for use by algebra
students from about 8th grade to college.
- Information about Polynomial Teacher
- download PT.EXE for dos
- Polynomial Teacher for Macintosh
- download C source for pt
- download pt for linux
- new port to java-enabled cellphones
jarfile by A. Carvalho
- devIFS and New IFS applet
- Create Iterated Function Systems! Experiment with ferns, galaxies,
etc. THis allows you to enter several affine
transformations of the plane by just clicking the mouse, 3 clicks for
each frame.
Run the new IFS Applet
Also the original macintosh program.
- download devIFS for Macintosh
Most of these programs are available at the Mathematics Archives,
which contains many other good things too. archives.math.utk.edu
Last Update: January 24, 2006
bterrell@math.cornell.edu