[quote=“Wile E. Coyote”]I guess you meet something like this:
[root.cern.ch/phpBB3/viewtopic.p … ors#p65423](Reading Histogram, Histogram drawing Empty
Try with (though, I do not know if your x-errros are properly considered in this case):
gre->Fit(“fpol”,“W”);[/quote]
Hi, Wile E. Coyote
Thank you for your reply.
I don’t know how ROOT deal with the error when fitting TGraph, it seems if I use the X error I provided, and the Y error which is the same to the TGraph fit, my problem should be solved.
I tried to set ye[i]=-1 in my code, it does not work. (if I set both xe and ye to -1, TGraphErrors fit is the same as TGraph fit) .
Hua