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I've been facing a problem with NaN causing exceptions in a project I'm working on. I was wondering if somebody could provide a list of all of the possible ways an NaN might surface in Java, so I could know all of the possible things to look for while tracking it down.

kabb
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  • You can post your code! We can work on the issue and it will be a lot easier for everyone to help you out in the best way. – Blue Ice Feb 28 '14 at 02:28
  • I have a fairly large code base, and I'm honestly not sure what code is relevant. – kabb Feb 28 '14 at 02:29
  • Possible duplicate of [When can Java produce a NaN?](http://stackoverflow.com/questions/2887131/when-can-java-produce-a-nan) – sigy Jan 31 '17 at 08:58

2 Answers2

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Source: https://stackoverflow.com/a/2887161/546060

NaN is triggered by the following occurrences:

  • results that are complex values
    • √x where x is negative
    • log(x) where x is negative
    • tan(x) where x mod 180 is 90
    • asin(x) or acos(x) where x is outside [-1..1]
  • 0/0
  • ∞/∞
  • ∞/−∞
  • −∞/∞
  • −∞/−∞
  • 0×∞
  • 0×−∞
  • 1∞
  • ∞ + (−∞)
  • (−∞) + ∞
Community
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Charles Goodwin
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  • Surprised I couldn't find that thread when I was trying to figure this out earlier. Thanks, that should (hopefully) help locate the problem. – kabb Feb 28 '14 at 02:39
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Here are some:

Double.NaN + Double.NaN  ->  NaN
Float.NaN + 2.0  ->  NaN
Float.NaN * 3.0  ->  NaN
(0.0 / 0.0) * Float.POSITIVE_INFINITY  ->  NaN
Math.abs(0.0 / 0.0) -> NaN

Taken from here.

PlasmaPower
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