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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