Bug in floating-point addition: is anyone else seeing this?

[Diez B. Roggisch]

Dave Parker wrote:

> On May 21, 7:01 pm, Carl Banks <pavlovevide... at gmail.com> wrote:
>> The crucial thing is not to slow down the calculations with useless
>> bells and whistles.
> 
> Are you running your simulations on a system that does or does not
> support the "useless bell and whistle" of correct rounding?  If not,
> how do you prevent regression towards 0?
> 
> For example, one of the things that caused the PS3 to be in 3rd place
> behind the Wii and XBox 360 is that to save a cycle or two, the PS3
> cell core does not support rounding of single precision results -- it
> truncates them towards 0.  That led to horrible single-pixel errors in
> the early demos I saw, which in term helped contribute to game release
> delays, which has turned into a major disappointment for Sony.

First of all - calling the PS3 technologically behind the WII (that is on
par with the PS2 wrt to it's computational power) is preposterous.

And that put aside, I don't get why a discussion about single or double
precision floats that SHARE THE SAME ROUNDING BEHAVIOR - just in different
scales - has to do with automatically adapting calculations to higher
precision numbers such as decimals or any other arbitrary precision number
format.

Diez