Wasn't it stbenge who wrote:
>Mike Williams wrote:
>> Wasn't it stbenge who wrote:
>>> Hi,
>>>
>>> I was wondering how POV is able to render coherent noise. Is it 
>>>truly  infinite, or just nearly? I've never seen a repeat, but 
>>>perhaps it  occurs just past the limit of observation.
>>>
>>> I'm coding a simple demo of randomly generated topography, with the 
>>>ability to scroll around the landscape. The only noise generators 
>>>I've  found reluctantly admit that the noise is "nearly infinite". I 
>>>want an  absolutely infinite landscape, but I don't know if it's even >>>possible.
>>  It's actually worse than that. Any finite computing system has a 
>>maximum  number that its arithmetic system can represent. That places 
>>an absolute  limit on the size of any landscape that the computer can 
>>represent,  whether it involves random elements or not.
>
>Well, I just made a random landscape generator, and it's huge. I'm sure 
>it repeats eventually, but I haven't seen it happen.

Well that's what you'd expect with "nearly infinite". I wouldn't expect 
to see any repetition in a landscape the size of the Earth.

>> It's possible to create hardware random number generators that are 
>>truly  random, using quantum effects, but they'd be useless for 
>>generating  randomly generated topology because they wouldn't produce 
>>the same  random numbers when you re-render the scene.
>
>I think we are still a ways off from seeing a commercial quantum 
>computer. Is there a way to achieve quantum effects apart from the 
>corresponding hardware?

Well you certainly can't write software that's sensitive to quantum 
fluctuations on a deterministic digital computer, so you either need 
some hardware that is sensitive to quantum fluctuations, or an external 
feed of data that is generated by such hardware. Such external data 
feeds include things like UK Premium Bond winning numbers and Lottery 
winning numbers.

[UK Premium Bond numbers use the signal noise in transistors. Each 
impact of the balls in a lottery machine doubles the angle of 
reflection, so after a few hundred impacts a difference in initial 
conditions at the quantum level would be amplified sufficiently to cause 
a different ball to be selected.]

We're not talking "quantum computers" here. That's something completely 
different.

-- 
Mike Williams
Gentleman of Leisure

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