[ROOT] bitted word: strange results

From: Luiz Martins Mundim Filho (Luiz.Mundim@cern.ch)
Date: Tue Aug 21 2001 - 19:17:24 MEST


Hi everybody

I got a strange results when ploting a ntuple variable with a bitted 
word cut. My ntuple has a multiplicity variable, called "Ncmul", and I 
want to plot it when the Igen bit number 1 and 3 are set and then, 
another plot with  Igen bit number 2 set. So I have executed the 
commands below:

root [61] h1->Draw("Ncmul","Igen&1<<2")
(Int_t)65845
root [62] cout << htemp->Integral()   
263380(class ostream)727080704
root [63] h1->Draw("Ncmul","Igen&1<<3")
(Int_t)71445
root [64] cout << htemp->Integral()   
571560(class ostream)727080704
root [65] h1->Draw("Ncmul","(Igen&1<<1)||(Igen&1<<3)")
(Int_t)71578
root [66] cout << htemp->Integral()                  
71578(class ostream)727080704

You can see that the output from root[62] doen't agree with the  one 
from 61, the same thing happens for the commands  63 and 64, but then, 
it worked for the command 65 and 66. I have tried a lot of other 
combinations, but the result is not coherent.

I realized this problem when doing:

root>h1->Draw("Ncmul","Igen&1<<2")
then
root>h1->Draw("Ncmul","Igen&1<<1 || Igen&<<3")

The scales was not correc, in despite of the number of eventos being 
similar.

Can someone tell me what is going wrong or what I am doing wrong????

Thanks a lot.

Luiz



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