Hi Inkyu, I understood your 6 steps. My question to you was: "How do you compute the error on the function at a point x ?" In case of functions such as "gaus", "expo", I understand how to do it, but not in a general case, except using a MonteCarlo technique by trying all parameter values in the estimated range of errors of the function parameters. May be somebody has a clever idea how to do it. Rene Brun icpark@mail.cern.ch wrote: > > Dear Rene, > > Here is what I am doing: > > 1) create a 1D profile histgram (TProfile) to see the correlation between > variables x and y. > > 2) fill the profile with x and y of an event (inside event loop) > > 3) the result profile histogram is fitted with "pol1" (errors are set) > > 4) save "pol1" into a file (function is saved with error) > > 5) open the file and access the function by > > TF1 *pol1=(TF1*)file.Get("pol1") > > 6) draw by pol1->Draw("e") <-- I'm hoping it pass the option "e" to > TH1::Draw(). > > I found that there is no option "e" in TF1::Draw(). My guess is that it > create/fill a histogram, but not set the error. Am I right? > > Regards, > Inkyu > > On Wed, 14 Nov 2001, Rene Brun wrote: > > > Hi Inkyu, > > > > What is your algorithm to compute the errors on the function ? > > > > Rene Brun > > > > On Wed, 14 Nov 2001 icpark@mail.cern.ch wrote: > > > > > Dear Rooters, > > > > > > Could somebody let me know how to draw a function (pol1 for example) with > > > error bar? > > > > > > Suppose we get a function "pol1" by fitting from a histogram. If I try > > > with TF1::Draw("e"), "e" is just my guess to plot error bars, it gives a > > > correct center line, but error bars are not the one from fit parameter. > > > > > > Ciao, > > > Inkyu > > > > > > > > > >
This archive was generated by hypermail 2b29 : Tue Jan 01 2002 - 17:51:08 MET