Re: [Discuss-gnuradio] accuracy problem?

[Eric Blossom]

On Wed, Jun 01, 2005 at 04:12:16PM -0400, David P. Reed wrote:
> I'm trying to install the gnuradio software from CVS on Fedora Core 3 on 
> an AMD64 (x86_64) laptop (and python 2.3).   Aside from annoying 
> pathname bugs and quirks with FFTW linking, which I will report 
> separately, I get the following error when testing gnuradio-core, where 
> a unittest fails.   Anyone who has a clue why this imprecision might be 
> happening?  If I change this one test to check for 5 digits after the 
> decimal point, it works...
> 
> Also, has anyone gotten gnuradio to run on x86_64?

Hi David,

Some folks have GNU Radio running on x86_64.  I just took delivery on
one the other day, but haven't had a chance to spend any time with it.

I think the difference you're seeing is that GCC for the x86_64 uses
the SSE scalar mode instructions at 32-bits instead of the x87
instructions with 80-bits of precision.

Eric