atlas G5 upgrade issue?

[vincent habchi]

Hi Ivan,

> When I went to upgrade atlas, I found it claiming it would be compiling for the G4 architecture (ppc) on a G5 (ppc64) machine, and that it would lead to inferior performance.  I do not recall seeing this on previous install/upgrades of atlas.  Does atlas have support for the G5 architecture?  If it does, what is preventing it from compiling for a G5?  Does anyone know of a workaround?  I'm on a G5, obviously, with MacPorts 1.9.2, and gcc 4.4.6.

I wrote a G5 support (ppc64) for Atlas, but it was difficult to debug. At a certain point in time, somebody pointed out that G5 floating point performance was not so different from G4, and that 64-bit instructions would fill the cache more quickly and maybe result in inferior performance. That's why I quit the ppc64 idea and fused both into a single ppc option. But if somebody is able to settle the G4/G5 dispute with definitive data about FP computing, I'll be happy to try to raise the ppc64 options from the deads.

Vincent