Handle ntuple leaves

ROOT
1

Hey there,

I’m working with these ntuples produces by COOL_IO (for those who what it is), and since I want to plot the data (current and voltage vs time), I’d like to know a few things.
My problem is that, in this root file, a “since” leaf is produced (which basically represents the time), but the thing is it contains time in nanoseconds since Jan 1st 1970 (!).
I thought about a few things :

  • is it possible to duplicate the ntuple, and divide all the values in this leaf by 1billion (I could then work with seconds) ?
  • should I read the ntuple, divide each value by 1billion, and rewrite it in another file
    -or si there a way to activate the time axis with time in nanoseconds (but i think im dreaming on this one…)

Anyway you can take a look at the file, which is in my public area :

/afs/cern.ch/user/a/arfaoui/public/306000.root

this is typically the structure I’d like to handle.

Thanks.

2

Hi,

To duplicate the file see the CloneTree example in $ROOTSYS/tutorials/tree

Philippe

3

Thank you, again I haven’t dug deep enough before asking.
Cheers.