NaN comparison

ROOT
1

Dear Expert,

When I compare two double numbers, if they are NaN, the result is false.

root [0] double a = 0./0;
root [1] double b = 0./0;
root [2] a
(double)nan
root [3] b
(double)nan
root [4] a == b
(int)0

So, is this expected?

Thanks

2

Hi,

I don’t know if CINT makes exception, but it seems to be the expected behaviour:

stackoverflow.com/questions/1526 … alues-in-c

3

Yes, it is expected, see: en.wikipedia.org/wiki/NaN

4

To check if a number is a NaN you can do:

root [3] TMath::IsNaN(a)
(Int_t)1

Knowing that you can adapt your code and make a more appropriate testing procedure.

1 Like