In article <cja### [at] netplexaussieorg> , 
Christopher James Huff <cja### [at] earthlinknet>  wrote:

> Still? Meaning they've used it before?

Yes, since August.  I had pointed out to them in detail that using
optics.pov is problematic (and got a response), but of course only after
they published first results in the print issue.  So it was too late for
them to change.  I suppose this is one reason why they now report results
for POV-Ray 3.1 as well as POV-Ray 3.5 again (in August they only reported
3.5 results).  As you know, the problem with optics.pov is that is spends a
lot of time in photon code, which is more searching than FPU usage.

> It is definitely not a good general benchmark scene, its purpose is to

Very true.

> demonstrate media photons. How could they miss the new benchmark scene,
> and what could make them choose optics.pov?

I don't know.  I guess they were afraid POV-Ray was specially optimized for
benchmark.pov, which to some extend is true (also not for specific
processors per-se), but it is still a better choice.  And optics.pov takes
reasonably long, so to someone who does not know the implementation details
it may seem like a good benchmark scene :-(

However, I have to admit that even when putting all the optimisation aside,
the raw benchmark.pov isn't a perfect benchmark as I found after doing some
extensive profiling.  It turns out a very few object types dominate the
tracing process, which creates a bias  and only evaluates a small amount of
code.  It can be fixed*, but then the scene looks really terrible...

    Thorsten

* I will post details elsewhere.

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message