# Chaos, Fractals

Some references...:

"A fractal is a rough or fragmented geometric shape that can be subdivided in parts, each of which is (at least approximately) a reduced-size copy of the whole. Fractals are generally self-similar and independent of scale".

"Chaos is apparently unpredictable behavior arising in a deterministic system because of great sensitivity to initial conditions."

Here's logistic.lisp, the file I was working on during the class, it contains functions you can evaluate and examples you can run. You'll also need to compile and load the plot.lisp (plot routines) and the v.ins (the fm violin)...

WARNING: close the plot before executing a with-sound (by doing a "(close-plot)"), execution of both will result in hanging the with-sound

From the Fractal FAQs

Q9: What is the logistic equation?
A9: It models animal populations. The equation is x -> c*x*(1-x), where x is the population (between 0 and 1) and c is a growth constant. Iteration of this equation yields the period doubling route to chaos. For c between 1 and 3, the population will settle to a fixed value. At 3, the period doubles to 2; one year the population is very high, causing a low population the next year, causing a high population the following year. At 3.45, the period doubles again to 4, meaning the population has a four year cycle. The period keeps doubling, faster and faster, at 3.54, 3.564, 3.569, and so forth. At 3.57, chaos occurs; the population never settles to a fixed period. For most c values between 3.57 and 4, the population is chaotic, but there are also periodic regions. For any fixed period, there is some c value that will yield that period. See "An Introduction to Chaotic Dynamical Systems" for more information.

lorenz.lisp has the Lorenz equation parser and note generator and some examples on its use.

The "lorenz" program that's being used in the previous examples is part of the source code for the book The Computational Beauty of Nature. There's source code available for all examples in the book (look in here for details on programs available and how they work). They have all been downloaded to this directory. The "bin/" subdirectory holds the compiled ready-to-run binaries for linux.