TMVA
TMVA version 4.1.1 is included in this root release. The changes with respect
to ROOT 5.28 / TMVA 4.1.0 are are in detail:
Variable transformations
- Variable transformations can now be applied to a user-defined subset
of variables (and regression targets).
- Enable variable transformations for general boosting
- Extended PDEFoam functionality:
- Multiclass classification by training of one discriminator foam for each
variable.
- The cell tree can now be plotted from the macro test/PlotFoams. This makes
it easyer to compare the PDEFoam structure to a decision tree.
- Variable importance ranking by counting the number of cuts made in each
dimension. The variable, for which the most cuts were done is ranked highest.
- Fixed the size of the sampling box in PDEFoam:
In TMVA 4.1.0 the size of the PDEFoam sampling box in each dimension was
2*VolFrac times the foam size. This was contrary to the intention and the
documentation in the UserGuide and is now corrected: In TMVA 4.1.1 the size
of the PDEFoam sampling box in each dimension is now VolFrac times the foam
size. This implies that in TMVA 4.1.1 the VolFrac value for training a PDEFoam
must be doubled in order to give the same results as in TMVA 4.1.0. The default
VolFrac value was also changed from 0.0333 to 0.0666.
- New configuration variable "NbinsMVAoutput" defining the bins of the MVA output
variables in the TMVA training plots produced via the GUI. As always, Config
settings can be modified in the training script via, eg, the command
(TMVA::gConfig().GetVariablePlotting()).fNbinsMVAoutput = 50;
to be called AFTER initialising the TMVA Factory object.
Bug fixes
- Fix for MethodBoost which ensures that the method options for the boosted
classifier are handled correctly during boosting.
- Fixed problems in classification of some methods when booking background
training tree before signal one.
- Fixed preprocessing transformation bug in HMatrix