Re: [ROOT] TH2 histograms and correlation factor.

From: Edmond Offermann (edmondoffermann@yahoo.com)
Date: Tue Aug 26 2003 - 17:35:41 MEST


Hi Sara,

Yes, TProfile is the way to go. Have a look at
TH2::ProfileX and TH2::ProfileY, where the first
one is used when your "controled" variable is x
and the second one for y.

Eddy

--- Sara VECCHIO <vecchio@pi.infn.it> wrote:
> Hi rooters!
> Here's a (maybe stupid) question from a quite new
> user.
> 
> I have a TH2 histogram scatter plot, in which points
> follows quite well an 
> exponential line. I need to check this hypotesis and
> to get the time 
> constant. 
> Using TH1::fit doesn't 
> work as I would (if I defined a TF2
> "y-[0]*exp(x/[1])" all the pad is 
> filled with black points!). 
> I've also tried to use
> TH2::GetCorrelationFactor(1,2) with a log scale 
> along y axis. But I'm not sure of what this function
> really does (ROOT 
> reference guide is sometimes too cryptic for me...),
> and it also look 
> insensitive to the log scale.
> I vaguely know that things should be easier with
> TProfile histograms, but 
> I don't know how to convert a TH2F in a TProfile.
> 
> Could someone help me?
> 
> Thanks in advance,
> Sara
> 
> 



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