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logistic map #26

Open jiegenghua opened 5 years ago

jiegenghua commented 5 years ago

Some study of the logistic map: image

I want to find if I give an initial value, what value it will converge to after iterating a lot of time.

(1) I set r<1, here r=0.5, iterate_num=1000, we only consider interval [0, 1]:

image

This image means no matter where I begin my initial value, it will converge to 0 after iterating a lot of time. This also means 0 is the only fixed point and is globally stable. (Here globally means [0,1]).

(2) I set r=1: image In this case, 0 is still the globally stable fixed point even though it does not satisfy the theorem we always use.

(3) r=2, image

Two fixed points, 0 and 1/2. 0 is the unstable one while 1/2 is the stable one. If the initial value is 0 and 1, it will converge to 0, otherwise 1/2.

(4)r=3 image

Two fixed points 0 and 2/3, both unstable.

(5)r=3.2 image

Two corresponding period-2 orbit, stable.

(6) r=4 image chaotic