making fractals in python

[evil_daffid]

hi,
Im reseaching fractals, and how to make them in python using recursion.
I've written a bit of code to make the koch isalnd but something isn't
right, I have the basic shape but there's something wrong with the
recursion i've used, could someone help me.

Here is the code im using:

import turtle
turtle.clear

def koch_line(line_ length, smallest):
third = line_length/3
if (third <= smallest):
turtle.forward( line_length)
else:
koch_line(third ,smallest)
turtle.right(90 )
if(third<=small est):
turtle.forward( line_length/2)
else:
koch_line(line_ length/2, smallest)
turtle.right(90 )
if (third <= smallest):
turtle.forward( third)
else:
koch_line(line_ length/2, smallest)
turtle.left(90)
if (third <= smallest):
turtle.forward( third)
else:
koch_line(line_ length,smallest )
if (third <= smallest):
turtle.forward( line_length)
else:
koch_line(third ,smallest)
turtle.right(90 )
if(third<=small est):
turtle.forward( line_length/2)
else:
koch_line(line_ length/2, smallest)
turtle.right(90 )
if (third <= smallest):
turtle.forward( third)
else:
koch_line(line_ length/2, smallest)
turtle.left(90)
if (third <= smallest):
turtle.forward( third)
else:
koch_line(line_ length,smallest )
return

def koch(line_lengt h, smallest):
koch_line(line_ length, smallest)
turtle.left(90)
koch_line(line_ length, smallest)
turtle.left(90)
koch_line(line_ length, smallest)
return

koch(500,10)

Thank you for your help

[evil_daffid]

Re: making fractals in python

Heres a link to the koch island:

http://mathworld.wolfram.com/LindenmayerSystem.html

[Ernst Noch]

Re: making fractals in python

evil_daffid wrote:[color=blue]
> hi,
> Im reseaching fractals, and how to make them in python using recursion.
> I've written a bit of code to make the koch isalnd but something isn't
> right, I have the basic shape but there's something wrong with the
> recursion i've used, could someone help me.
>
> Here is the code im using:
>[/color]
[Code snipped]

Is this a homework assignment or something?

Anyway, this is a little bit more pythonic and flexible, though my
python has gotten a little bit rusty. It uses L-Systems for state storage.
Recursion is only left in because you asked for it.
Iterate() should get more sophisticated for more complex string
substitutions.

import turtle
turtle.clear

class fractal(object) :

def __init__(self, lstring, rule, line_length, angle,
shrink_factor):
self.lstring = lstring
self.rule = rule
self.line_lengt h = line_length
self.angle = angle
self.shrink_fac tor=shrink_fact or

def draw(self):
drawingdict = {'F': lambda: turtle.forward( self.line_lengt h),
'-':lambda: turtle.right(se lf.angle),
'+':lambda: turtle.left(sel f.angle),}
for rule in self.lstring:
drawingdict[rule]()

def iterate(self):
self.lstring = self.lstring.re place(rule[0],rule[1])
self.line_lengt h=self.line_len gth/self.shrink_fac tor

def recurse(f,small est):
if f.line_length>= smallest:
turtle.reset()
f.iterate()
f.draw()
recurse(f,small est)

if __name__=='__ma in__':
start = 'F+F+F+F'
rule = ('F','F+F-F-FF+F+F-F')
f = fractal(start,r ule,50,90,2)
recurse(f,10)