Problem with ProjectionX/Y Function

ROOT
1

Hi,

I have a two dimensional histogram that I create using the ratio funtion (using 2 2D hists as arguments). The values in the 2D ratio hist are always < or =1 (they are efficiencies). I then get a ID profile by doing:

TH1D * proj_1 = h_Ratio1->ProjectionY(“proj_1”, 1,max," ");

This gives me the right shape but the values on the Y axis are no longer less than 1, it seems that the projection funtion is summing all the values in my bins 1 to max but not then dividing by the number of bins. Is this a bug? How can I get a 1D projection of a 2D hist and it gives me the average values of the bins rather than the totals?

Thanks, Claire

2

Hello,

if you want the average values and not the global sum, you have to project on a TProfile, by using TH2::ProfileY

Cheers

Lorenzo