TF1 evaluate error based on user-fed covariance matrix

Hello all,

     I understand how to get the integral error of a TF1 that I manually give the covariance matrix to along with the parameter values. I want to do this with specific values. For example, I use Eval(double x) and I want it to also give me the errors on that functional value. Thank you


There is not a generic method to do that for a TF1 (i.e. to get the error on the evaluate x, given the parameters and their covariance matrix).
However, after a fit you can use the GetConfidenceInterval function of the Fitter or FitResult class. An example of this is the tutorial fit/ConfidenceIntervals.C
see … als.C.html

Best Regards