Need a working example of Find Threshold (Meta) operator in RapidMiner
I've been working with text classification processes in RapidMiner and I can't figure out the proper way to use Find Threshold (Meta) operator for multiclass classification which seems to be the closest one to implement Threshold family operators used for binary classification.
I am using k-NN models and have 11 different classes and a corpus of about 300-500 text documents as test dataset.
Specifically, I don't see any impact of putting a learner inside the operator since performance values are always the same, whether I do assign any weights to the classes or not. Moreover, there's no explanation what are the weights of classes are. And moreover, I don't see any way to extract (possibly) generated thresholds as the output of this operator in order to apply them to the model. And there's no RapidMiner documentation entry for this operator at all.
Does anyone have a working example of Find Threshold (Meta) operator so far?
I am using k-NN models and have 11 different classes and a corpus of about 300-500 text documents as test dataset.
Specifically, I don't see any impact of putting a learner inside the operator since performance values are always the same, whether I do assign any weights to the classes or not. Moreover, there's no explanation what are the weights of classes are. And moreover, I don't see any way to extract (possibly) generated thresholds as the output of this operator in order to apply them to the model. And there's no RapidMiner documentation entry for this operator at all.
Does anyone have a working example of Find Threshold (Meta) operator so far?