[Radiance-general] Deterministic calculations with Radiance

[Greg Ward]

Perhaps.  If the pixel sampling rate were high enough (e.g. pfilt -x 
/10 -y /10), you might get some stability.  At that point, you 
shouldn't have to worry about the random number generator.  However, 
the MC ray tracing literature is full of examples where even 200+ 
samples/pixel is not enough to avoid large variance in some regions, 
and the same can be true for Radiance, especially with specular 
samples.

-G

> From: Randolph Fritz <randolph at panix.com>
> Date: February 4, 2005 9:48:23 AM PST
>
> On Thu, Feb 03, 2005 at 11:09:33PM -0800, Greg Ward wrote:
>> Yes, but what's the point?  A change in the compiler or a minor
>> alteration of the code that makes no difference to the results but
>> affects the order in which rays are traced will completely defeat such
>> a test.  How can we do regression testing with something that 
>> unstable?
>
> Could we perhaps "blur" the two light maps before comparing them?
>
> Randolph