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Viewing changes to pyturtle/tdemo_chaos.py

  • Committer: Jono Bacon
  • Date: 2010-04-24 18:14:20 UTC
  • mfrom: (93.3.2 python-snippets-bzr)
  • Revision ID: jono@system76-pc-20100424181420-hup208wuekhvr1qc
A bunch of PyTurtle snippets. Thanks, Grant!

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pyturtle/tdemo_chaos.py
 
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#!/usr/bin/env python
 
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#
 
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# [SNIPPET_NAME: Chaos]
 
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# [SNIPPET_CATEGORIES: PyTurtle]
 
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# [SNIPPET_DESCRIPTION: Use turtle to graph chaos.]
 
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# [SNIPPET_DOCS: http://docs.python.org/library/turtle.html]
 
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# [SNIPPET_AUTHOR: Grant Bowman <grantbow@ubuntu.com>]
 
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# [SNIPPET_LICENSE: PSF]
 
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# Code authorship from http://python.org/download/releases/2.6.4/
 
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# File: tdemo_chaos.py
 
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# Author: Gregor Lingl
 
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# Date: 2009-06-24
 
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# A demonstration of chaos
 
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from turtle import *
 
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N = 80
 
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def f(x):
 
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    return 3.9*x*(1-x)
 
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def g(x):
 
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    return 3.9*(x-x**2)
 
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def h(x):
 
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    return 3.9*x-3.9*x*x
 
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def jumpto(x, y):
 
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    penup(); goto(x,y)
 
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def line(x1, y1, x2, y2):
 
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    jumpto(x1, y1)
 
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    pendown()
 
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    goto(x2, y2)
 
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def coosys():
 
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    line(-1, 0, N+1, 0)
 
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    line(0, -0.1, 0, 1.1)
 
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def plot(fun, start, colour):
 
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    pencolor(colour)
 
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    x = start
 
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    jumpto(0, x)
 
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    pendown()
 
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    dot(5)
 
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    for i in range(N):
 
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        x=fun(x)
 
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        goto(i+1,x)
 
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        dot(5)
 
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def main():
 
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    reset()
 
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    setworldcoordinates(-1.0,-0.1, N+1, 1.1)
 
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    speed(0)
 
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    hideturtle()
 
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    coosys()
 
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    plot(f, 0.35, "blue")
 
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    plot(g, 0.35, "green")
 
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    plot(h, 0.35, "red")
 
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    # Now zoom in:
 
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    for s in range(100):
 
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        setworldcoordinates(0.5*s,-0.1, N+1, 1.1)
 
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    return "Done!"
 
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if __name__ == "__main__":
 
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    main()
 
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    mainloop()