Fitting Fails to Return Fit Results

ROOT
1

Hello PyROOT Experts,

First off, PyROOT is great, however I have run into an odd quark…

I am trying to use the “S” option with the Fit method to have it return a TFitResultPtr from which I can get a Covariance Matrix as shown at root.cern.ch/root/html/TH1.html#TH1:Fit under “Access to the fit result”

Here are the two relevant lines of code:
fitResults = plot.Fit(“Fit_”+name,“SQr”)
fitResults.GetCovarianceMatrix()

And get the following error:

    AttributeError: 'int' object has no attribute 'GetCovarianceMatrix'

I have done a type of fitResults both with and without the S option and in both cases I get int.

I am using ROOT 5.22/00d (branches/v5-22-00-patches@29532, May 26 2010, 20:34:00 on macosx) which is distributed with CMS’s reconstruction software.

Thanks,
Michael

2

TFitResult is only implemented in 5.26 or newer

Rene

3

Alright that is good to know! Thanks, now hopefully someone will reply to my install issue question in 5.27. =)

Thanks,
Michael