[alt.fractals] iterated functions plotter

callahan@mimsy.umd.edu (Jack Callahan) (10/06/90)

I'm looking for a plotting package that will draw orbit
diagrams for iterated functions for viewing things like
bifurcations.  I heard of something called MAPPER, but
haven't be able to locate it.

Something else that would nice is a plotting package that
displays the function and then shows the behavior of the
iterated of a particular point (specified by the user).
It might even draw the lines from f(x) to the line x=y
back to f(x), etc. used to illustrate the effects of
attracting and repelling fixed points and their basins.

Thanks for any feedback.

BCNU,

-- jack



-- 
Jack Callahan - callahan@brillig.umd.edu
Computer Science Department
University of Maryland, College Park
<insert a cute and witty disclaimer here>

scavo@cs.uoregon.edu (Tom Scavo) (10/06/90)

In article <26866@mimsy.umd.edu> callahan@mimsy.umd.edu (Jack Callahan) writes:
>I'm looking for a plotting package that will draw orbit
>diagrams for iterated functions for viewing things like
>bifurcations.  I heard of something called MAPPER, but
>haven't be able to locate it.

Fractint ver. 14 includes a few routines that draw orbit
diagrams for the logistic function and a trigonometric
mapping (type = bifurcation, biflambda, bif+sinpi, bif=sinpi).
That's the only noncommercial package that I know of
(anybody else know of others?).  Although I haven't seen it,
I understand that the program Chaos in the Classroom by
Dynamical Systems, Inc. will do bifurcation diagrams for
eight different mappings.  If you care to program yourself,
see chapter 4 of _Chaos,_Fractals,_and_Dynamics_ by R.L.
Devaney for an elegant algorithm in Basic.  The basic idea
of an orbit diagram is incredibly simple.

>Something else that would nice is a plotting package that
>displays the function and then shows the behavior of the
>iterated of a particular point (specified by the user).
>It might even draw the lines from f(x) to the line x=y
>back to f(x), etc. used to illustrate the effects of
>attracting and repelling fixed points and their basins.

Chaos in the Classroom claims to be able to do this for
its menu of eight mappings, and so will Phaser for just
about any function you can think of.  Also, there's an
algorithm (again in Basic) in Barnsley's _Fractals_
_Everywhere_ (and again in chapter 4) that will draw the
"stair step" or "web" diagram that you ask for.

Hope this helps.
-- 

Tom Scavo  <scavo@cs.uoregon.edu>
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