From: Sébastien Gadrat <gadrat_at_clermont.in2p3.fr>

Date: Tue, 15 Feb 2005 18:36:17 +0100

Date: Tue, 15 Feb 2005 18:36:17 +0100

Hi Rooters,

I am fitting some spectra with a functional which is made in several
elementary components (a sum of more simple functions, each of them
representing a given contribution to my spectrum). Each elementary
function has one and only one free parameter (this parameter can be use
to determine the integral of the given component so the number of events
which are in it).

But I would like to constrain some parameters to move only within a
given interval, whose bounds are given by another free parameter (but
fixed at a given moment of the minimization). I would like my interval
to be updated for each new step to take into account previous value
returned by the previous step for the free parameter it depends.
As an example, I am fitting some J/psi and psi prime spectra and I want
that the number of psi prime is let say within 1/30 and 1/70 times the
number of J/psi. I know about TF1::SetParLimits but I do not think I can
use it in my case since I do not know the magnitude of my different
contribution before fitting and my interval will not be updated at all
while minimization...

Is there a way to do that in ROOT ?

Thanks in advance,

Best regards,

Sebastien Received on Tue Feb 15 2005 - 18:36:25 MET

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