Root Minimizer Configuration

The RootMinimizer uses ROOT to apply numeric minimization to the likelihood and find the best fit point.

Config options

These are the minimizerInterfaceConfig fields that are supported by when the minimizer type is set to RootMinimizer.

minimizerConfig Options	Type	Description	Default
type	string	Must be “RootMinimizer” for this configuration
checkParameterValidity	bool	Turn on parameter validity checks (in physical, in domain, etc)	false
showParametersOnFitMonitor	bool	Display fit parameter parameter values on the monitor	false
enablePostFitErrorFit	bool	Evaluate the Hessian after the fit	true
maxNbParametersPerLineOnMonitor	int	Number of parameters on a monitor line	15
useNormalizedFitSpace	bool	use fit parameter interface to provide prior mean at 0 and stddev at 1	true
writeLlhHistory	bool	write a ttree registering all the llh evaluations	false
Root Minimizer Specific	Type	Description	Default
minimizer	string	engine name	Minuit2
algorithm	string	algorithm name	default from engine
errors	string	algorithm to run after the fit (HESSE or MINOS)	Hesse
tolerance	double	defines the required Estimated Distance from the Minimum stopping the fit	1E-4
maxFcnCalls	int	maximum number of function calls before stopping fit	1E9
maxIterations	int	maximum number of minimizer iterations before stopping fit	500
strategy	int	fitter strategy (sec. 1.3)	1
print_level	int	minimizer verbose level (p.23)	1
enableSimplexBeforeMinimize	bool	run SIMPLEX before the real fit (can help to find the minimum)	false
enablePostFitErrorFit	bool	Evaluate the Hessian after the fit	true
simplexMaxFcnCalls	int	stop SIMPLEX after N calls	1000
simplexToleranceLoose	int	loosen the minimizer tolerance by this factor during SIMPLEX	1000
simplexStrategy	int	strategy for SIMPLEX	1
generatedPostFitParBreakdown	bool	Generate figures showing hessian eigen decomp breakdown by parameter	false
generatedPostFitEigenBreakdown	bool	Generate figures showing parameter breakdown by hessian eigen	false
monitorRefreshRateInMs	int	Max refresh rate for the fit monitor in milliseconds	5000
monitorGradientDescent	bool
tolerancePerDegreeOfFreedome	int