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29 Sep 2024 19:21:41 EDT (-0400)
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From: scott
Subject: Re: Random stuff
Date: 30 Apr 2009 10:48:37
Message: <49f9ba45@news.povray.org>
> But yes, I'm pretty sure this system possesses such a property. 

It might depend on how much damping you give it.


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From: Invisible
Subject: Re: Random stuff
Date: 30 Apr 2009 10:54:28
Message: <49f9bba4@news.povray.org>
scott wrote:
>> But yes, I'm pretty sure this system possesses such a property. 
> 
> It might depend on how much damping you give it.

Doubt it.

Consider a point exactly between two attractors. A particle at this 
point experiences zero resultant force. Purturbing the point by any 
finite amount to either side will make the resultant force non-zero. 
This will cause a different path to be traced, regardless of how much 
damping is applied.

In general, applying more damping makes the system *less* unstable, but 
does not remove areas of chaotic behavious; it just makes them smaller.


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From: Invisible
Subject: Re: Random stuff
Date: 30 Apr 2009 10:55:28
Message: <49f9bbe0@news.povray.org>
Invisible wrote:

>> Now, if you add more than one attractor.....
> 
> ...it goes completely scatty! o_O

Twisted and tangled, baby! :-D


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Attachments:
Download 'test_drawmany.jpg' (48 KB)

Preview of image 'test_drawmany.jpg'
test_drawmany.jpg


 

From: Invisible
Subject: Re: Random stuff
Date: 30 Apr 2009 11:15:20
Message: <49f9c088$1@news.povray.org>
As an aside, I tried to implement this on my laptop at the weekend, but 
it was hopelessly unstable. Today it seems very stable indeed. I can 
only assume this is to do with replacing Euler with 4th-order 
Runge-Kutta. I'm surprised it makes quite this much of a difference 
though...


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From: Kevin Wampler
Subject: Re: Random stuff
Date: 30 Apr 2009 14:29:00
Message: <49f9edec@news.povray.org>
Invisible wrote:
> Consider a point exactly between two attractors. A particle at this 
> point experiences zero resultant force. Purturbing the point by any 
> finite amount to either side will make the resultant force non-zero. 
> This will cause a different path to be traced, regardless of how much 
> damping is applied.
> 
> In general, applying more damping makes the system *less* unstable, but 
> does not remove areas of chaotic behavious; it just makes them smaller.

I think you may have some misconceptions about what chaos is.  First 
off, sensitivity to initial conditions is a necessary but *not 
sufficient* condition for chaotic behavior.  Secondly your example of a 
point between the two attractors only argues for this sensitivity at a 
manifold of points, and many many non-chaotic systems have such a 
feature (for example a simple pendulum).

Thirdly, although it's possible I'm wrong here, if you have *any* 
dampening I don't think the system can be counted as chaotic because all 
paths will eventually converge to a point.  If the system would be 
chaotic without dampening it's sort of a minor point since it can still 
look a lot like chaos, but technically I think it's incorrect to call it 
chaotic.

Finally, I'm not sure that your system is chaotic.  For inverse-square 
springs it's known as Euler's three-body problem and appears to have a 
(rather complicated) analytic solution.


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From: Kevin Wampler
Subject: Re: Random stuff
Date: 30 Apr 2009 14:32:18
Message: <49f9eeb2$1@news.povray.org>
Kevin Wampler wrote:
> Finally, I'm not sure that your system is chaotic.  For inverse-square 
> springs it's known as Euler's three-body problem and appears to have a 
> (rather complicated) analytic solution.

This is for just two attractors of course with three or more I'd be 
pretty surprised if it weren't chaotic (and I wouldn't be too surprised 
to find out I'm wrong about the two attractor system).

Also, neat pictures!  You should color-plot the basins of attraction 
when you have a dampening factor.


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From: Orchid XP v8
Subject: Re: Random stuff
Date: 30 Apr 2009 15:12:24
Message: <49f9f818@news.povray.org>
Kevin Wampler wrote:

> Also, neat pictures!  You should color-plot the basins of attraction 
> when you have a dampening factor.

This is my goal. Unfortunately, the GTK+ subsystem is giving me some 
spurious error message about a missing DLL or some such stupidity... *sigh*

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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From: andrel
Subject: Re: Random stuff
Date: 30 Apr 2009 15:21:18
Message: <49F9FA2C.2030803@hotmail.com>
On 30-4-2009 21:12, Orchid XP v8 wrote:
> Kevin Wampler wrote:
> 
>> Also, neat pictures!  You should color-plot the basins of attraction 
>> when you have a dampening factor.
> 
> This is my goal. Unfortunately, the GTK+ subsystem is giving me some 
> spurious error message about a missing DLL or some such stupidity... *sigh*
> 
You could use something like POV to do that for you...


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From: Orchid XP v8
Subject: Re: Random stuff
Date: 30 Apr 2009 15:26:48
Message: <49f9fb78$1@news.povray.org>
>>> Also, neat pictures!  You should color-plot the basins of attraction 
>>> when you have a dampening factor.
>>
>> This is my goal. Unfortunately, the GTK+ subsystem is giving me some 
>> spurious error message about a missing DLL or some such stupidity... 
>> *sigh*
>>
> You could use something like POV to do that for you...

I could use PPM too. It's just irritating that GTK+ has decided to stop 
working today. :-/

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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From: andrel
Subject: Re: Random stuff
Date: 30 Apr 2009 15:43:27
Message: <49F9FF5D.7070208@hotmail.com>
On 30-4-2009 21:26, Orchid XP v8 wrote:
>>>> Also, neat pictures!  You should color-plot the basins of attraction 
>>>> when you have a dampening factor.
>>>
>>> This is my goal. Unfortunately, the GTK+ subsystem is giving me some 
>>> spurious error message about a missing DLL or some such stupidity... 
>>> *sigh*
>>>
>> You could use something like POV to do that for you...
> 
> I could use PPM too. It's just irritating that GTK+ has decided to stop 
> working today. :-/
> 
I am sure you didn't change anything


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