Maximum number of parameters in a user defined fit

ROOT
1

hi
i have a problem conserning the maximum number of parameters possible in a fit with a user defined function. I m trying to fit many gaussian functions heaped on top of each other in this way

Double_t fitf2g(Double_t *x, Double_t *p)
{
return p[0]*TMath::Gaus(*x,p[1],SIGMA)+p[2]*TMath::Gaus(*x,p[3],SIGMA)+p[4]*TMath::Gaus(*x,p[5],SIGMA)+
p[6]*TMath::Gaus(*x,p[7],SIGMA)+p[8]*TMath::Gaus(*x,p[9],SIGMA);
}

As i understand there is a maximum of 10 parameters possible in this kind of fit.the same applies if you combine functions. Is there any way to increase this number?

thanks in advance

2

see an example for ftting multiple gaussians in $ROOTSYS/tutorials/spectrum/peaks.C

Rene

3

thank you for your anwser Rene it was very helpfull. I have one question about the peaks c. example. I don t see where the noise is coming from. Is it the FillRandom line?

Primoz

4

As indicated in the comments at the top of the script:

// This script generates a random number of gaussian peaks // on top of a linear background.
Rene