# File: tdemo_chaos.py
# Author: Gregor Lingl
# Date: 2009-06-24
# A demonstration of chaos
from turtle import *
N = 80
def f(x):
return 3.9*x*(1-x)
def g(x):
return 3.9*(x-x**2)
def h(x):
return 3.9*x-3.9*x*x
def jumpto(x, y):
penup(); goto(x,y)
def line(x1, y1, x2, y2):
jumpto(x1, y1)
pendown()
goto(x2, y2)
def coosys():
line(-1, 0, N+1, 0)
line(0, -0.1, 0, 1.1)
def plot(fun, start, color):
pencolor(color)
x = start
jumpto(0, x)
pendown()
dot(5)
for i in range(N):
x=fun(x)
goto(i+1,x)
dot(5)
def main():
reset()
setworldcoordinates(-1.0,-0.1, N+1, 1.1)
speed(0)
hideturtle()
coosys()
plot(f, 0.35, "blue")
plot(g, 0.35, "green")
plot(h, 0.35, "red")
# Now zoom in:
for s in range(100):
setworldcoordinates(0.5*s,-0.1, N+1, 1.1)
return "Done!"
if __name__ == "__main__":
main()
mainloop()
