This is a very simple question I suspect but I just cannot seem to nail it...
I have values for $X,Y,Z $, where $X =\log (x)$, $Y = \log (y)$ and $Z = \log (z)$ and I need to calculate $x + y + z$, well actually $\log(x + y + z)$ would suffice. Is there a clever way of doing this other than simply doing $e^X+e^Y+e^Z$?
Its for an algorithm where I am trying to avoid underrun - $x=e^X,y=e^Y,z=e^Z$ likely to be very small.
Any pointers much appreciated.
With answer given by @response I ended up using $\log(x+y+z)=\log(e^R+e^S+e^T)-C$ where $R=X+C$, $S=Y+C$, $T=Z+C$