TF1 GetMinimumX()

Hi
I’m having a problem with TF1 GetMinimumX(). The class documentation states:
// First, the grid search is used to bracket the maximum
// with the step size = (xmax-xmin)/fNpx. This way, the step size
// can be controlled via the SetNpx() function.

When I change fnpx from the default 100 to a larger number (say 1000) I do not see any change in how the program runs (eg. it still only runs over 100x). Looking at 5.28.00 I see that the source has changed in a way that sets fnpx properly.
I’m running v5.26.00, and it is not simple for me to change versions currently. Is there no way to set fnpx? a possible workaround?

Trevor

HI,

Yes a grid search of 100 is hard-coded in the code (by mistake) in 5.26 and it is fixed now in versions >= 5.28.
If you cannot upgrade, the only work around is to do a grid search yourself, for example calling the MinimStep and MinimBrent functions (defined in Math/BrentMethods.h ) yourself as it is done in BrentMinimizer1D::Minimize
(see root.cern.ch/viewvc/trunk/math/m … iew=markup )

Lorenzo