Re: [ROOT] TProfile with variable bin sizes

From: Nick van Eijndhoven (Nick@phys.uu.nl)
Date: Tue Feb 25 2003 - 16:17:03 MET


Hi Rene,
Then probably I misunderstood something; as I said it was "my cents".
Having a derived class TProfileX is also fine with me; I only thought
that the procedure I suggested would give less (programming) overhead
and would keep TProfile more general.
But clearly you know the underlying structure best, so I put my
faith in your hands :).

                                                   Cheers,
                                                    Nick. 

Rene Brun wrote:
> 
> Hi Nick,
> 
> I have to disagree with you. The case with derivation is precisely
> to avoid any overhead for users not interested by the new feature.
> 
> Rene Brun
> 
> Nick van Eijndhoven wrote:
> >
> > Hi Rene,
> > Here is my 2 cents.
> > In case of a new class TProfileX deriving from TProfile, one creates
> > an unnecessary overhead to my opinion, since some data arrays are
> > then always unused.
> > Why not introduce a new memberfunction TProfile::SetX()
> > (or whatever name) which acts in a way like TH1::Sumw2().
> > This would mean that in case one calls SetX before one starts filling,
> > the TProfile::Fill will internally interchange the roles of X and Y
> > and the mean and rms of X will be computed etc...
> > As far as I can judge this would be a most direct way of achieving the
> > desired functionality.
> >
> >                                                        Cheers,
> >                                                         Nick.
> >
> > --
> > Dr. Nick van Eijndhoven mailto:nick@phys.uu.nl http://www.phys.uu.nl/~nick
> > --------------------------------------------------------------------------
> > Org.:    Utrecht University, Faculty of Physics and Astronomy
> > Address: Princetonplein 5, NL-3584 CC Utrecht, The Netherlands
> > Phone:   +31-30-2532331(direct) +31-30-2531492(secr.)  Fax: +31-30-2518689
> > CERN:    +41-22-7679751(direct) +41-22-7675857(secr.)  Fax: +41-22-7679480
> > Offices: Buys Ballot laboratory Room 710 (Utrecht)   B23 1-020 (CERN)
> > --------------------------------------------------------------------------
> >
> > Rene Brun wrote:
> > >
> > > Hi Alberto,
> > >
> > > Your analysis is correct. A TProfile does not compute the mean/rms for each bin
> > > along x. I agree that this would be an interesting addition.
> > > This extension could be implemented in two ways
> > >   - new class TProfileX  deriving from TProfile with two additional
> > > arrays           to accumulate sum(w*x) and sum(w*x*x) for each bin
> > >   - extend the existing TProfile with again 2 possibilities
> > >     - by default compute the mean/rms per bin
> > >     - as an option
> > > It would be trivial to extend the Fit functions to take into account the errors
> > > per bin along x.
> > >
> > > Comments are welcome.
> > >
> > > Rene Brun
> > >
> > > Alberto Garcia Raboso wrote:
> > > >
> > > > Hi ROOTers,
> > > >
> > > > I need a variable bin size profile, and so I have had a look on the code
> > > > to see what it makes. The problem is that ROOT takes the mean and the
> > > > standard deviation only along the y axis, but not in the x axis. Later on
> > > > I need to fit the points (x_{m}, y_{m}), where x_{m} is the mean of the
> > > > points alog the x axis, and y_{m} the mean along the y axis, weighted eith
> > > > the error along the y axis.
> > > >
> > > > Does anybody know a way to do it, without having to use a TGraphErrors and
> > > > to calculate all the errors manually?
> > > >
> > > > Thanks in advance,
> > > >
> > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > Alberto Garcia Raboso
> > > > Universidad Autónoma de Madrid (Spain)
> > > > E-Mail: Alberto.Garcia.Raboso@cern.ch
> > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > > Well, farewell, my hobbits! You should come safe to your own
> > > > homes now, and I shall not be kept awake for fear of your
> > > > peril. We will send word when we may, and some of us may yet
> > > > meet at times; but I fear that we shall not all be gathered
> > > > together ever again.
> > > >
> > > >                       The return of the King. J.R.R. Tolkien
> > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



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