Weight by PCA

Synopsis

This operator creates attribute weights of the ExampleSet by using a component created by the PCA. This operator behaves exactly the same way as if a PCA model is given to the Weight by Component Model operator.

Description

The Weight by PCA operator generates attribute weights of the given ExampleSet using a component created by the PCA. The component is specified by thecomponent numberparameter. If thenormalize weightsparameter is not set to true, exact values of the selected component are used as attribute weights. Thenormalize weightsparameter is usually set to true to spread the weights between 0 and 1. The attribute weights reflect the relevance of the attributes with respect to the class attribute. The higher the weight of an attribute, the more relevant it is considered.

主成分分析(PCA)是一种数学al procedure that uses an orthogonal transformation to convert a set of observations of possibly correlated attributes into a set of values of uncorrelated attributes called principal components. The number of principal components is less than or equal to the number of original attributes. This transformation is defined in such a way that the first principal component's variance is as high as possible (accounts for as much of the variability in the data as possible), and each succeeding component in turn has the highest variance possible under the constraint that it should be orthogonal to (uncorrelated with) the preceding components.

Input

example set

This input port expects an ExampleSet. It is the output of the Retrieve operator in the attached Example Process.

Output

weights

This port delivers the weights of the attributes with respect to the label attribute. The attributes with higher weight are considered more relevant.

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

Normalize weights

This parameter indicates if the calculated weights should be normalized or not. If set to true, all weights are normalized in the range from 0 to 1.

Sort weights

This parameter indicates if the attributes should be sorted according to their weights in the results. If this parameter is set to true, the order of the sorting is specified using thesort directionparameter.

Sort direction

This parameter is only available when thesort weightsparameter is set to true. This parameter specifies the sorting order of the attributes according to their weights.

Component number

This parameter specifies the number of the component that should be used as attribute weights.