# Divide TH1F histogram: Weird Results

Hi Rooters
I am declaring four histograms with same number of bins:

[color=#FF0000] TH1F *TotalEventssumPT_EF_j100_a4tc_EFFS_ht400 = new TH1F(“TotalEventssumPT_EF_j100_a4tc_EFFS_ht400”,“sumPT for events”, 200, 0.0, 2000.0);
TH1F *TotalEvents_T27_sumPT = new TH1F(“TotalEvents_T27_sumPT”,"",200, 0.0, 2000.0);
TH1F *Efficiency_T27_by_T7 = new TH1F(“Efficiency_T27_by_T7”,"",200, 0.0, 2000.0);
TH1F *Efficiency_T7_by_T7 = new TH1F(“Efficiency_T7_by_T7”,"",200, 0.0, 2000.0);
[/color]
Then I am filling the first three histograms in a loop. Now, I am dividing 2nd histogram by 1st histogram and saving it as 3rd histogram. As cross-check, I am dividing 1st histogram by itself (hoping that it should be exactly 1.0) and saving it as 4th histogram.

``````    [color=#FF0000]Efficiency_T27_by_T7 -> Divide(TotalEvents_T27_sumPT , TotalEventssumPT_EF_j100_a4tc_EFFS_ht400 , 1.0 , 1.0 );
Efficiency_T27_by_T7 -> Write();
Efficiency_T7_by_T7 -> Divide( TotalEventssumPT_EF_j100_a4tc_EFFS_ht400 , TotalEventssumPT_EF_j100_a4tc_EFFS_ht400 , 1.0 , 1.0 );
Efficiency_T7_by_T7 -> Write();[/color]
``````

However, I am not getting 1 which means that division is not being carried out correctly. Can someone point out the bug in it.
Cheers
Aatif

Solved it. Many thanks.