class RooTreeDataStore: public RooAbsDataStore

 Constructor to facilitate reading of legacy RooDataSets

 Protected constructor for internal use only

 Initialize cache of dataset: attach variables of cache ArgSet
 to the corresponding TTree branches

 Destructor

 One-time initialization common to all constructor forms.  Attach
 variables of internal ArgSet to the corresponding TTree branches

 Create TTree object that lives in memory, independent of current
 location of gDirectory

 Load values from tree 't' into this data collection, optionally
 selecting events using 'select' RooFormulaVar

 The source tree 't' is first clone as not disturb its branch
 structure when retrieving information from it.

 Load values from dataset 't' into this data collection, optionally
 selecting events using 'select' RooFormulaVar

 Return true if currently loaded coordinate is considered valid within
 the current range definitions of all observables

 Interface function to TTree::Fill

 Load the n-th data point (n='index') in memory
 and return a pointer to the internal RooArgSet
 holding its coordinates.

 Change name of internal observable named 'from' into 'to'

 Add a new column to the data set which holds the pre-calculated values
 of 'newVar'. This operation is only meaningful if 'newVar' is a derived
 value.

 The return value points to the added element holding 'newVar's value
 in the data collection. The element is always the corresponding fundamental
 type of 'newVar' (e.g. a RooRealVar if 'newVar' is a RooFormulaVar)

 Note: This function is explicitly NOT intended as a speed optimization
       opportunity for the user. Components of complex PDFs that can be
       precalculated with the dataset are automatically identified as such
       and will be precalculated when fitting to a dataset

       By forcibly precalculating functions with non-trivial Jacobians,
       or functions of multiple variables occurring in the data set,
       using addColumn(), you may alter the outcome of the fit.

       Only in cases where such a modification of fit behaviour is intentional,
       this function should be used.

 Utility function to add multiple columns in one call
 See addColumn() for details

 Merge columns of supplied data set(s) with this data set.  All
 data sets must have equal number of entries.  In case of
 duplicate columns the column of the last dataset in the list
 prevails

 Cache given RooAbsArgs with this tree: The tree is
 given direct write access of the args internal cache
 the args values is pre-calculated for all data points
 in this data collection. Upon a get() call, the
 internal cache of 'newVar' will be loaded with the
 precalculated value and it's dirty flag will be cleared.

 Activate or deactivate the branch status of the TTree branch associated
 with the given set of dataset observables

 Remove tree with values of cached observables
 and clear list of cached observables

 Interface function to TTree::GetEntries

 Interface function to TTree::Reset

 Interface function to TTree::Fill

 Interface function to TTree::GetEntry

 Tree access

 TTree Branch buffer size control