Problem with MINOS when the derivative around the minimum is discontinuous (TMinuit)

Hi,

I am having troubles with MINOS when I am minimising a likelihood which has a discontinuous derivative at the minimum for a given parameter. I call MIGRAD twice followed by MINOS. Strangely, Minuit does not generate any warning and MIGRAD convergence is successful (although the step size goes down to 7e-14 for that parameter and the first derivative to 1e4 while the fitted value is 2.5e-7), but MINOS returns a "PROBLEMS" status and returns only the parabolic error for that parameter.

I have tried the strategies 0, 1 and 2 but they all produce the same status at the end. Is there some kind of trick with Minuit to avoid that kind of problem?

Thanks! Received on Sat Jul 17 2010 - 06:58:30 CEST