I'll do you one better; you can turn a negative zero into a positive
zero leaving other values unchanged like this:
d = d + 0.0;
In IEEE 754 under the round-to-nearest-even rounding mode required by Java
-0.0 + 0.0 => (+)0.0
This trick is used in various places in Java's numerical libraries, is
required behavior by our specifications, and even has some tests for it :-)
-Joe
On 6/7/2013 8:43 AM, David Chase wrote:
Wouldn't be more efficient to do the following, assuming that the full Java
compilation chain respects the trickiness of 0 vs -0:
if (d == 0.0) {
d=0.0 // Jam -0 == +0 to +0, per
http://www.w3.org/TR/xpath/#function-string
}
Division's plenty more expensive than assigning a constant, especially on
platforms that lack hardware FP division.
David
On 2013-06-07, at 2:03 AM, huizhe wang <huizhe.w...@oracle.com> wrote:
Hi Aleksej,
According to XPath spec, both positive and negative zero are converted to the
string 0, so it seems doesn't matter. But if you want to detect the negative
zero, you may do the following:
if (d == 0.0 && 1/d < 0.0) {
d=0.0
}
Recognizing that (-0.0 == 0.0), and (1/(-0.0) == -Infinity).
-Joe
