[Radiance-general] multi-processing on SGI Onyx

[Rob Guglielmetti]

Roland Schregle wrote:

> WOW!!! A predator rack!!! Somebody around here still uses *REAL*
> hardware! To hell with dual pentium boards! :^)

Yes to hell with them.  Real (financially challenged) men run their 
simulations on Athlon systems.  =8-)

> I'll leave it to Greg to eggs-plain what avlmemi does wrong. Possibly a
> portability bug, but not peculiar to IRIX. Also pops up under Linux.
> Nuthin' wrong with your Onyx, that's for sure.

Sometimes it pays to be an email pack-rat.  Here's a snippet from an old 
email exchange between Greg & I:

" ... I got very annoyed about the avlmemi bug after the workshop, 
thinking about these things that have been dogging me for so many years, 
so I did a little investigation on the OS X version, where to my horror 
the same problem had come up, again.  Fortunately, I had an easily 
reproduced error, so I was able to do a little experimentation.  All 
these years, I thought it was a bug in the qsort(3) library routine, but 
on further testing, I couldn't get it to fail, so I started to look 
elsewhere.  As it turned out, it wasn't the qsort() function itself, 
rather it was the comparison function I was giving it in ambient.c.  I 
was comparing two pointers using pointer arithmetic, using an expression 
that works with most compilers, but apparently not GNU-C!  In the end, 
it was a single word that needed to be changed to rid me of this bug 
that's been hanging on for at least 6 years, since the first Linux 
systems came into widespread use."

There you go.  Maybe I saved Greg some typing.

----

      Rob Guglielmetti

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