[Radiance-general] multiprocessor systems, Radiance, and you

[Rob Guglielmetti]

Hi Schorsch:

Georg Mischler wrote:

> What this means is that you *can* use a dual CPU machine to its
> full potential, without any further tools necessary. The only
> thing that you need to do is split up your vector sets into two,
> and start a seperate rtrace process with each half. If all
> preprocessing (mkillum etc) is already done, then they will
> happily share their ambient file, which accelerates both of them.
> As long as you stay on the same box, you'll also definitively
> have no locking problems.

OK, thanks.  Your info suggests that I could just build a dual box, 
install Linux and Radiance, and continue doing things the way I am doing 
them (multiple shell scripts calling rtrace), and both cpus would be 
fully utilized.  Maybe I'll still go that route, I don't know.  A single 
Athlon 2400XP goes for less than $200 US though, and I like the 
redundancy of having my processors in two separate machines.

I was hoping for the ability to make both cpus appear as one, 
transparently to Radiance.  PAB says this is not doable at the kernel 
level.  I'm running shell scripts that simulate a series of days for 
daylighting analysis.  The whole thing is fairly linear, and even the 
sharing of the ambient file is not necessary because when the script 
advances to the next hour, the octree is different, and thus the 
previous calculation's ambient cache is not valid for the next one.  I 
already have separate scripts/rtrace processes for each day, but was 
hoping to make all the days run off one command, hence my desire for 
"one" fast box.  I guess I was looking for one terminal window to run 
everything from, in order, with one command.  I'm lazy.

> I didn't check: Is PVM also available for Windows?

Yes (http://www.csm.ornl.gov/pvm/pvm_home.html).  Maybe the beginnings 
of the next feature of Rayfront?  =8-)

----

      Rob Guglielmetti

e. rpg@rumblestrip.org
w. www.rumblestrip.org