Skip to main content

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 the method parameter. 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 constant 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 the attribute parameter. 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 (Deprecated) 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 the label attribute. 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 constant 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 the attribute parameter.

constant​

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

attribute name​

This parameter is only available when the method parameter 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.