[ROOT-3452] Suggestions for Minimizer documentation

[vepadulano]

Explain what you would like to see improved and how.

From https://its.cern.ch/jira/browse/ROOT-3452

I have some specific suggestions on improving the documentation for the minimizer classes:

• TFitterMinuit should have a deprecation warning and point to the new style classes

• It would be useful to have the ROOT::Math::Minimizer page give a simple example of its use, or at least point to the tutorial NumericalMinimization.C

• ROOT::Math::Minimizer::SetLimitedVariable is undocumented, and the arguments are unnamed. Just putting names on the arguments would help.

• The page for ROOT::Math::IBaseFunctionMultiDim could specifically mention ROOT::Math::Functor, since that seems the most appropriate way to use one's own function with the fitting framework.

I hope these can be added - they would make the documentation a lot easier for users new to the whole fitting framework.

ROOT version

Any

Installation method

Any

Operating system

Any

Additional context

No response

[ferdymercury]

• TFitterMinuit should have a deprecation warning

Does it refer to etc/plugins/TVirtualFitter/P030_TFitterMinuit.C or to what class exactly?