Unbinned fit in 2 dimensions

ROOT
1

Hi,

I`m having a problem with the Tree::UnbinnedFit() function. What i have is an tntuple with several branches of data, and I would like to find the fit parameters that match one column to the next (i.e. I expect frequency to be proportional to temp + temp^2). Is UnbinnedFit() the correct way to do this?

If it is, could someone give me the function call to UnbinnedFit() that will give me the 2-d fit? I would expect it would be something like
tree.UnbinnedFit(“pol2”,“x:y”), but I`m not at all sure.

Thanks, Andy

2

Andy,

With a “pol2” you can fit only a 1-D distribution, ie something like
tree.UnbinnedFit(“pol2”,“x”);
or using “y” as a weight
tree.UnbinnedFit(“pol2”,“x”,“y”);

If you want to fit “x:y” you must give a 2-d function

Rene