| The Logistic Map [message #1835] |
Thu, 03 March 1994 13:00 |
darren
Messages: 5
Registered: March 1994
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Junior Member |
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Keywords:
Greetings.
I am trying to plot out the evolution of the logistic equation,
iterating x(i+1)=r*x(i)(1-x(i)), for r in [0,4). I'd like IDL to plot a
point for each value through the iteration. The problems are that I keep
getting floating underflows, and I can't generate the right results. The
code is just this simple bit:
Function Map, r, x
return, r*x*(1.0-x)
END
Pro Logistic
y = intarr(100) & y(*) = 0
plot, y, xrange = [0, 4], yrange = [0, 1]
for i = 0,799 do begin
r = i/200.0
x = 0.5
for j = 0, 299 do begin
x = Map(r,x)
endfor ; to get rid of transients
for j = 0, 1999 do begin
x = Map(r,x)
k = fix(x * 600) ; plot the nearest integer
; to x*600
plots, r, k
endfor
END
In addition to this particular example, is there a much more optimal way of
doing recursive calculations in IDL about which I'm simply not aware?
Thanks in advance.
-Darren Orbach
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