Problem constructing TH2F

ROOT
6

(Number of bins = array_dimension) gives:

root [0] Double_t b_f[9]={0.,0.1,0.16,0.2,0.25,0.3,0.35,0.4,0.6};
root [1] TH2F*h=new TH2F("a","a",10,0,1,9,b_f)
Error in <TAxis::TAxis::Set>: bins must be in increasing order
root [2]

(Number of bins = array_dimension-1) gives:

root [0] Double_t b_f[9]={0.,0.1,0.16,0.2,0.25,0.3,0.35,0.4,0.6};
root [1] TH2F*h=new TH2F("a","a",10,0,1,8,b_f)
root [2]

That’s logic, the array defines the bins’ boundaries.