Minuit2 Issue with parameter names

I have found that when fitting a TF1 to a TH1 using Minuit2, the minimiser fails if multiple parameters have the same name.

It seems the parameters with the shared name end up being assigned internally over one another, which also messes up the indexing for any other parameters.

Once I found this was the issue I was able to rename my parameters to solve it, but it took a while to determine. If this is not fundamental to how minuit2 indexes parameters, perhaps it can be corrected, else a clearer note in the TF1 documentation would be good.

ROOT Version: 6.30/02
Platform: linuxx8664gcc
Compiler: c++ (Ubuntu 9.4.0-1ubuntu1~20.04.2) 9.4.0

Dear James,

Thanks for the interesting post.
While we take good note of this observation, let me add @moneta and @jonas, experts of ROOT math infrastructure, in the loop.


This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.