[Rivet] Fwd: FourMomentum mass

[Sercan Sen]

It seems that it's looking for mass2() > 0 to return mass value,  
however, it does not work, I guess.

Ok, that's good to learn, I can remove those values by putting a cut.

Cheers
Sercan






On Nov 11, 2010, at 1:32 AM, Hendrik Hoeth wrote:

> Thus spake Sercan Sen (Sercan.Sen at cern.ch):
>
>> And, please can somebody explain why we have those values (NaN) ?
>
> Photons tend to have a fairly low rest mass, both in nature and in  
> Monte
> Carlo. Combine this with the fact that computer have a limited  
> numerical
> accuracy, and you get sqrt(small_negative_number_instead_of_zero). At
> least from time to time. Guess we should catch that. In fact I thought
> we had already fixed this several months ago.
>
> Cheers,
>
>    Hendrik
>
> -- 
> One doesn't discover new lands without consenting to lose
> sight of the shore for a very long time.    -- André Gide

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