[Radiance-general] Deterministic calculations with Radiance

[Christopher Kings-Lynne]

Hmmm, I guess I still don't quite get it...

You are using many calls to random() or something.  If you srandom a 
certain seed, why is it not possible to get the same output every time?

Sorry...

Chris


Gregory J. Ward wrote:
> I didn't really explain this right.  The problem is not just different 
> implementations -- but what I said earlier about thresholded values 
> causing the random number sequence to get off track.  There's no easy 
> fix for this, and trying to reproduce exact pixel values will always be 
> a problem with any Monte Carlo renderer.  If you don't believe me, try 
> it yourself.
> 
> -G
> 
>> From: Randolph Fritz <randolph at panix.com>
>> Date: February 2, 2005 9:16:58 AM PST
>>
>> On Wed, Feb 02, 2005 at 06:21:18AM -0800, Gregory J. Ward wrote:
>>
>>>
>>> The ideal approach would be to use a pseudo-random number generator
>>> that is repeatable.  In principle, Radiance does this, but due to
>>> differences between machines and implementations, in practice it does
>>> not work out that way.
>>>
>>
>> Why not incorporate some random number generators with Radiance,
>> instead of relying on whatever the system happens to provide?
>>
>> Randolph
> 
> 
> 
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