I do not see why when I run my TMVAMulticlass (1) in the output I (2) see 4 background instead of 3 and it calls tha last one “Background” and it does not have any entries? Do you see what is wrong?
Try changing the name
Signal to something else.
it does not change anything.
It’s because of
SetBackgroundWeightExpression. In multiclass, this function should only be called with
AnalysisType=Classification. (This could be made more clear). Because of this, the function assumes a class named “Background” will exist.
If you want to have the same weight expression for a number of classes, you have to specify it several times.
dataloader->SetWeightExpression("expr", "bg0"); dataloader->SetWeightExpression("expr", "bg1"); dataloader->SetWeightExpression("expr", "bg2");