I got rid of my previous problem of PAR archive and custom library.
At this moment, I am really running PROOF to understand the idea of running parallel workers.
So this question is more theoretical.
I have a tree with 5 quantities:
- a “run” number ( a running number currently I am between 250000 and 260000)
- a “spill” number (from 1 to 200)
- a “counter” (from 1 to … the infinite or whatever, it’s usually millions)
- a “timeinspill” value (from 1 to 15 secondes)
I would like to plot run:spill for example. Nevertheless, I noticed that TSelector::Init() is called each time a new TTree is cached.
Basically you have :
Begin() BeginSlave() Init() Process() Init() Init() EndSlave() [.. repeat ..] Terminate()
- I create my histogram when I use BeginSlave();
- Usually I set my tree pointer at the Init() function.
Here is the problem… If I want to draw “timeinspill:spill” that’s work because it’s a well known range.
But when I want to display “timeinspill:counter” or “run:spill”, I don’t know how to initialize my histogram !! Since I don’t know the upper limit of my histogram.
I am working with ROOT 5.34.36, I tried many things… But is there a easy solution to correctly draw this ?
I already tried to Input a value before using TChain::Process(), but that doesn’t make sense… because I have to read all my tree…
Any comment is very welcome