Hello ROOT forum, good evening
I (am still beginner in TMVA he) want to use classification methods (ANN and BDT), so I already have generated the correspondent file .root, and I have ROOT 6.12.04 and I am trying to modify the code of the macro TMVAClassification.C, but I don’t understand this part:
line 210…
// Define the input variables that shall be used for the MVA training
// note that you may also use variable expressions, such as: “3var1/var2abs(var3)”
// [all types of expressions that can also be parsed by TTree::Draw( “expression” )]
dataloader->AddVariable( “myvar1 := var1+var2”, ‘F’ );
dataloader->AddVariable( “myvar2 := var1-var2”, “Expression 2”, “”, ‘F’ );
dataloader->AddVariable( “var3”, “Variable 3”, “units”, ‘F’ );
dataloader->AddVariable( “var4”, “Variable 4”, “units”, ‘F’ );
// You can add so-called “Spectator variables”, which are not used in the MVA training,
// but will appear in the final “TestTree” produced by TMVA. This TestTree will contain the
// input variables, the response values of all trained MVAs, and the spectator variables
dataloader->AddSpectator( “spec1 := var12", “Spectator 1”, “units”, ‘F’ );
dataloader->AddSpectator( "spec2 := var13”, “Spectator 2”, “units”, ‘F’ );
I suppose that var1, var2, var3, var4, are the physical input parameters. It is correct? What mean variables myvar1, myvar 2,spec1, spec2…? Are they really necessary to achieve a classification?
Thanks for your attention,
Sincerely
Karen