Default Model

Synopsis

This operator generates a model that provides the specified default value as prediction.

Description

The Default Model operator generates a model that predicts the specified default value for the label in all examples. The method to use for generating a default value can be selected through themethodparameter. For a numeric label, the default value can be median or average of the label values or a constant default value can be specified through the常数parameter. For nominal values the mode of the labels can be used. Values of an attribute can be used as predictions; the attribute can be selected through theattributeparameter. This operator should not be used for 'actual' prediction tasks, but it can be used for comparing the results of 'actual' learning schemes with guessing.

Input

training set

This input port expects an ExampleSet. It is the output of the Retrieve operator in the attached Example Process. The output of other operators can also be used as input.

Output

model

The default model is delivered from this output port. This model can now be applied on unseen data sets for the prediction of thelabelattribute. This model should not be used for 'actual' prediction tasks, but it can be used for comparing the results of 'actual' learning schemes with guessing.

example set

The ExampleSet that was given as input is passed without changing to the output through this port. This is usually used to reuse the same ExampleSet in further operators or to view the ExampleSet in the Results Workspace.

Parameters

Method

This parameter specifies the method for computing the default values. For a numeric label, the default value can be median or average of the label values or a constant default value can be specified through the常数parameter. For nominal values the mode of the labels can be used. Values of an attribute can be used as predictions; the attribute can be selected through theattributeparameter.

Constant

This parameter is only available when themethodparameter is set to 'constant'. This parameter specifies a constant default value for a numeric label.

Attribute

This parameter is only available when themethodparameter is set to 'attribute'. This parameter specifies the attribute to get the predicted values from. If applied on a nominal label, it should be made sure that the selected attribute has the same set of possible values as the label.