clipka <ano### [at] anonymousorg> wrote:
> Am 22.05.2011 14:05, schrieb gregjohn:
>
> > You all may save me the embarrassment of asking someone with a more powerful
> > computer to run the code to compare. (Um, asking a second person).  While I do
> > work in computer hardware, it's on the purely physical side (processing
> > defects), not the system architecture side. But would every computer give the
> > same image for the floating point errors? Any coolness / art/ science in
> > comparing those?
>
> The images are unlikely to differ much: The noise will appear at the
> same level of depth regardless of system architecture. After all, on
> virtually all systems interim results will be stored in IEEE
> double-precision floats, no more and no less.
>
> However, depending on some compiler settings and/or system architecture
> details, the actual noise pattern may differ due to different default
> float rounding mode, differences in the precision for computations (e.g.
> extended double precision on "classic" x86 systems using the x87
> instructions, vs. standard double precision on systems supporting SSE2),
> and maybe other such details.


Interesting. I remember something years ago about how you could do some sort of
repeated calculation with a calculator and get to its floating point error
regime, and supposedly every calculator were different #declare urban_myth=off.
Exploring this concept for fun in povray.

Post a reply to this message