Emittance calculation

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Thank you @eguiraud

  1. hemitxxpsp is a TH2F in which on x axis I plot the position (i.e. the branch PositionDirection.x ) and on y axis I plot the angle (i.e. the branch SecondaryParticleAng.x ). In my formula I need the mean value both of PositionDirection.x and SecondaryParticleAng.x (i.e. < x > and < x’>). For erro I wrote GetRMS() but I need GetMean().
    Given that I need both the means of x and y axis, here Mean from a 2d histogram found that I must use GetMean(1) for the x axis and GetMean(2) for the y one! Did I understand right?

  2. I wrote


float x;	
			float xp;
			float xm;
			float xpm;
			float xxpmN;
			float xxpm;
			int jentry;
			int nentries = ts->GetEntries();
			xm= hemitxxpsp->GetMean(1);
			xpm= hemitxxpsp->GetMean(2);
			ts->SetBranchAdress("PositionDirection.x",PositionDirection.x,"x/I");
			ts->SetBranchAdress("SecondaryParticleAng.x",SecondaryParticleAng.x,"xp/I");
		    for(jentry=0; jentry<nentries;jentry++) {
			ts->GetEntry(jentry);
				xxpmN+= (x-xm)*(xp-xpm);
			}
			xxpm=xxpmN/nentries;

but I get these errors

image
image1021×324 17.9 KB

anyway, I wrote a very short macro (just 52 lines), please, can you check it? I think it’s easier for you to help me looking this very shor macro

simlemmared.cpp (1.6 KB)