MinuitMinimizer¶

class minkit.MinuitMinimizer(evaluator, **minimizer_config)[source]¶

Bases: minkit.Minimizer

Interface with the iminuit.Minuit class. In the calls to the different methods of this class it is ensured that the parameters of the PDF(s) from the evaluator instance have their value set to that of the minimum after a minimization process.

Parameters: evaluator (UnbinnedEvaluator, BinnedEvaluator or SimultaneousEvaluator) – evaluator to be used in the minimization.

Attributes Summary

`evaluator`	Evaluator of the minimizer.
`minuit`	Underlying `iminuit.Minuit` object.

Methods Summary

`asymmetric_errors`(name[, cov, sigma, atol, …])	Calculate the asymmetric errors for the given parameter.
`fcn_profile`(wa, values)	Evaluate the profile of an FCN for a set of parameters and values.
`hesse`(args, *kwargs)	Arguments are forwarded to the `iminuit.Minuit.hesse()` function, and the values of the parameters are set to those from the minimization result.
`migrad`(args, *kwargs)	Arguments are forwarded to the `iminuit.Minuit.migrad()` function, and the values of the parameters are set to those from the minimization result.
`minimization_profile`(wa, values[, …])	Minimize a PDF an calculate the FCN for each set of parameters and values.
`minimize`(args, *kwargs)	Same as `MinuitMinimizer.migrad()`, but offering a common interface for all the `Minimizer` objects.
`minos`(args, *kwargs)	Arguments are forwarded to the `iminuit.Minuit.minos()` function, and the values of the parameters are set to those of the MINOS result.
`restoring_state`()	Method to ensure that modifications of parameters within a minimizer context are reset properly.
`set_parameter_state`(name[, value, error, fixed])	Method to ensure that a modification of a parameter within a minimizer context is treated properly.

Attributes Documentation

evaluator¶: Evaluator of the minimizer.

minuit¶: Underlying iminuit.Minuit object.

Methods Documentation

asymmetric_errors(name, cov=None, sigma=1, atol=1e-08, rtol=1e-05, maxcall=None)¶

Calculate the asymmetric errors for the given parameter. This is done by subdividing the bounds of the parameter into two till the variation of the FCN is one. Unlike MINOS, this method does not treat new minima.

Parameters

name (str) – name of the parameter.
cov (numpy.ndarray) – covariance matrix. If provided, the initial values of the parameters will be obtained from them.
sigma (float) – number of standard deviations to compute.
atol (float) – absolute tolerance for the error.
rtol (float) – relative tolerance for the error.
maxcall (int or None) – maximum number of calls to calculate each error bound.

fcn_profile(wa, values)¶

Evaluate the profile of an FCN for a set of parameters and values.

Parameters

wa (str or list(str)) – single variable or set of variables.
values (numpy.ndarray) – values for each parameter specified in wa.

Returns

Profile of the FCN for the given values.

Return type

numpy.ndarray

hesse(*args, **kwargs)[source]¶

Arguments are forwarded to the iminuit.Minuit.hesse() function, and the values of the parameters are set to those from the minimization result.

Returns: Output from iminuit.Minuit.hesse().

migrad(*args, **kwargs)[source]¶

Arguments are forwarded to the iminuit.Minuit.migrad() function, and the values of the parameters are set to those from the minimization result.

Returns: output from iminuit.Minuit.migrad().

minimization_profile(wa, values, minimizer_config=None)¶

Minimize a PDF an calculate the FCN for each set of parameters and values.

Parameters

wa (str or list(str)) – single variable or set of variables.
values (numpy.ndarray) – values for each parameter specified in wa.
minimizer_config (dict or None) – arguments passed to Minimizer.minimize().

Returns

Profile of the FCN for the given values.

Return type

numpy.ndarray

minimize(*args, **kwargs)[source]¶: Same as MinuitMinimizer.migrad(), but offering a common interface for all the Minimizer objects. It returns a tuple with the information whether the minimization succeded and the covariance matrix.

See also

MinuitMinimizer.migrad

minos(*args, **kwargs)[source]¶

Arguments are forwarded to the iminuit.Minuit.minos() function, and the values of the parameters are set to those of the MINOS result. If a new minimum is found, the value of the parameter is set accordingly.

Returns: output from iminuit.Minuit.minos().

restoring_state()[source]¶: Method to ensure that modifications of parameters within a minimizer context are reset properly. Sadly, the iminuit.Minuit class is not stateless, so each time a parameter is modified it must be notified of the change.

Warning

This does not preserve the minimization state of MIGRAD.

set_parameter_state(name, value=None, error=None, fixed=None)¶

Method to ensure that a modification of a parameter within a minimizer context is treated properly. Sadly, the iminuit.Minuit class is not stateless, so each time a parameter is modified it must be notified of the change.

Parameters

name (str) – name of the parameter.
value (float or None) – new value of a parameter.
error (float or None) – error of the parameter.
fixed (bool or None) – whether to fix the parameter.