Recent Improvements of the ROOT Fitting and Minimization Classes

Advanced mathematical and statistical computational methods are required by the LHC experi- ments for analyzing their data. Some of these methods are provided by the Math work package of the ROOT project, a C++ Object Oriented framework for large scale data handling appli- cations. We present in detail the recent developments of this work package, in particular the recent improvements in the fitting and minimization classes, which have been re-designed and re- implemented with an object-oriented approach. New minimization algorithms have been added recently in ROOT and they can be used consistently for fitting via a common interface. These al- gorithms include Minuit2, the new object-oriented version of Minuit, various minimization meth- ods from the GNU Scientific libraries, stochastic and genetic algorithms. Furthermore, a new graphical user interface has been also developed for performing and monitoring fits on ROOT data objects such as histograms, graphs and threes in both one or multi-dimensions. We will de- scribe in detail the new capabilities provided by the new fitting and minimization classes and the functionality of the new user interface.