How to check "Math::Mnimizer" status?

Hello all,

I have a question regarding the ROOT::Math::Minimizer.

I had performed the Log-likelihood on my energy reconstruction algorithm.
But sometimes, error(i think it was failed case) has occurred even though same events & same data.

Error message is below,

FUNCTION VALUE DOES NOT SEEM TO DEPEND ON ANY OF THE 4 VARIABLE PARAMETERS.
VERIFY THAT STEP SIZES ARE BIG ENOUGH AND CHECK FCN LOGIC.

According to my personal investigation, all input parameter for minimization was all ‘-nan’.

I think there are some randomized thing in the minimizing process.
So i want to check the status of minimizing process.
I already checked the item like,
–> minimizer->Status()
–> minimizer->MinValue()

Is there any recommendation or tips to check the condition of my minimization process?

Thank you


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_ROOT Version:6.16.00
_Platform: CentOS Linux
_Compiler:g++ 4.8.5


Hi,

The error message is quite clear. The function seems not to depend on the parameters, so there is an error in the function you passed to the minimiser.
Also , what is a nan ? Probably the computed function value. This is another indication of a mistake in the function. In case you have regions where the function is not defined, you should protect it by setting bounds on the parameters.

Lorenzo

1 Like

Hi Lorenzo,
Oh… thanks it clear to me.
i think that nan is a giving parameter for minimization due to my mistake.
Now i founded one solution to fix this and check this as well.
Thank you for your comments.

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