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Loop Attribute Subsets

Synopsis​

This operator iterates over its subprocess for all possible combinations of regular attributes in the input ExampleSet. Optionally, the minimum and maximum number of attributes in a combination can be specified by the user.

Description​

The Loop Attribute Subsets operator is a nested operator i.e. it has a subprocess. The subprocess of the Loop Attribute Subsets operator executes n number of times, where n is the number of possible combinations of the regular attributes in the given ExampleSet. The user can specify the minimum and maximum number of attributes in a combination through the respective parameters; in this case the value of n will change accordingly. So, if an ExampleSet has three regular attributes say a, b and c. Then this operator will execute 7 times; once for each attribute combination. The combinations will be {a},{b},{c},{a,b},{a,c},{b,c} and {a,b,c}. Please study the attached Example Process for more information.

This operator can be useful in combination with the Log operator and, for example, a performance evaluation operator. In contrast to the brute force feature selection, which performs a similar task, this iterative approach needs much less memory and can be performed on larger data sets.

Input​

example 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​

example set​

The ExampleSet that was given as input is delivered through this port without any modifications.

Parameters​

Use exact number​

If this parameter is set to true, then the subprocess will be executed only for combinations of a specified length i.e. specified number of attributes. The length of combinations is specified by the exact number of attributes parameter.

Exact number of attributes​

This parameter determines the exact number of attributes to be used for the combinations.

Min number of attributes​

This parameter determines the minimum number of attributes to be used for the combinations.

Limit max number​

If this parameter is set to true, then the subprocess will be executed only for combinations that have less than or equal to m number of attributes; where m is specified by the max number of attributes parameter.

Max number of attributes​

This parameter determines the maximum number of attributes to be used for the combinations.