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Article #392

Need to find variance of a fractal

#392
From: Gerry Roston
Date: Thu, 24 Mar 1994 22:55
37 lines
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I have implemented the routine AdditionsFM1D from page 86 of the book
_The Science of Fractal Images_. This routine used midpoint
displacements with successive random additions. At each step, a
variance is calculated and points are placed using this variance. My
question is this: Can the variance for the fractal as a whole be
determined analytically from the variances at each step? For example,
assuming a fractal dimension of H, the variance at each step is
given by:

          1               1        1
 del ^2 = - sig^2 (1 - -------) (-----)
    n     2               2-2H     2Hn
                         2        2

where sig is the initial standard deviation and n is the level of the
recursion. What I want is a formula:

 s.d. = sigma * f(n, H)

where s.d. is the standard deviation of the generated fractal. I know
that I can simply collect statistical data from the fractal and
calculate the s.d. in that manner, but I need a solution in this form.

Please respond by email as I do not follow all of these groups. Thanks
in advance for your help.

--
Gerry Roston (gerry@cmu.edu)    | [the most perfect form of popular
Field Robotics Center,          | government is that] where the least injury
Carnegie Mellon University      | done to meanest individual, is considered
Pittsburgh, PA, 15213           | as an insult on the whole constitution.
(412) 268-3856                  | Solon
                                |
The opinions expressed are mine |
and do not reflect the official |
position of CMU, FRC, RedZone,  |
or any other organization.      |
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From: gerry@cmu.edu (Gerry Roston)
Subject: Need to find variance of a fractal
Message-ID: <GERRY.94Mar24175525@onion.cmu.edu>
Roureply-To: gerry@cmu.edu (Gerry Roston)
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Organization: Field Robotics Center, CMU
Date: Thu, 24 Mar 1994 22:55:25 GMT
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