Hi everyone,

Sorry I have to ask this question which may seems basic to you.

My question concern the histograms! So, I know there is TH1,TH2,TH3

1/

But if I would like to add a signal into an histogram (for example (t,y) ) then, should I use :

-TH1 : hisot->Fill(t,y) (FFT.C example)

-TH2 :histo->Fill(t,y)

Ps:My signal is not a math expression to evaluate, but a set of data points I read from an ASCII file.

I think that the 2 solutions are right, but if so! what’s the difference then between TH2 and TH1

2/

When I create a TH2D histogram, with:

for(expression)

{

for(i=0,i<N;i++)

{

histo->fill(index,t[i],y[i]);

}

index++;

}

I’m using this solution when I have millions of data lines in y, so I take sub signals of y with the length N.

What should then number of xbins and ybins at that case?

Thank you in advance!