LOG10E mystery constant

John Cowan cowan at mercury.ccil.org
Sun Feb 20 21:26:40 PST 2011


Mark S. Miller scripsit:

> This is the only constant whose actual value differs across browsers:
> 
> 0.43429448190325176   v8 version 2.3.9 [console: dumb]
> 0.4342944819032518     Chrome 11.0.672.2 dev

[etc.]

The two values are really the same value when represented as an IEEE
double.  The difference is in the printing routine, not the internal
representation.  Specifically, the "...2518" browsers are rounding, the
"...25176" browsers are not.

"Floating-point numbers are a little like sandpiles; every time you pick
one up, you get a little less sand and a little more dirt."  (But this
is not true of integers up to 2^53, slightly less than 10^16.

-- 
John Cowan                                <cowan at ccil.org>
Yakka foob mog.  Grug pubbawup zink wattoom gazork.  Chumble spuzz.
    --Calvin, giving Newton's First Law "in his own words"


More information about the test262-discuss mailing list