Problem in fitting: Abnormal termination of minimization

Dear all,

I am trying to fit some points (please find that attached)
with a function of type: p0 + p1/x^{p2}

It is giving me warning:

Warning in <Fit>: Abnormal termination of minimization. FCN=0.36281 FROM MIGRAD STATUS=CALL LIMIT 1345 CALLS 1346 TOTAL EDM=0.00011369 STRATEGY= 1 ERROR MATRIX UNCERTAINTY 26.5 per cent EXT PARAMETER APPROXIMATE STEP FIRST NO. NAME VALUE ERROR SIZE DERIVATIVE 1 Const 2.34916e-01 1.93354e-02 1.59776e-04 -7.12223e-01 2 b 6.79464e+08 2.99201e+09 3.09998e+07 -1.50918e-10 3 power 6.28887e+00 1.29026e+00 1.39157e-02 3.45751e-01

But it fits the points.
Then I try to get the confidence intervals from this fit by doing:

and then it gives me (in addition to above warnings):

Error in <TBackCompFitter::GetConfidenceIntervals>: Cannot compute confidence intervals with an invalide fit result

What would you suggest in this case?


Best Regards,


The minimization exceeded the number of calls. You can try to extend by setting to a larger value (e.g. 10000).


Also you could try to increase the tolerance for convergence:



Hello Lorenzo,

Many thanks.

worked for me.

Best Regards,