First Valid Score Combiner

The First Valid score combiner is used in conjunction with the RLINK score combiner (see TIBCO Patterns Machine Learning Platform and Using a Learn Model in a Search). It is used to select a querylet based on its confidence value. For more information on the use cases for this score combiner, see the section "TIBCO Patterns Learn Features" in the TIBCO® Patterns Concepts Guide that explains handling and finding low confidence pairs.

This combiner takes the standard set of options for query combiners. In addition it takes the following values in the LPAR_LST_QOPTS list:

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LPAR_DBLARR_CONFIDENCE_CUTOFFS is the cutoff value for the confidence value of the querylets. This value is required and must have the same number of elements as there are querylets for this combiner. If the LPAR_BOOL_INVALID_ONLY flag is present and true this value represents a maximum confidence value; if the associated querylet has a confidence value greater than this value it is skipped. If LPAR_BOOL_INVALID_ONLY is not given, or is false, and the associated querylet has a confidence value less than this value, it is skipped. All values must be in the range 0.0 to 1.0 inclusive.

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LPAR_DBLARR_MATCH_CUTOFFS is the cutoff threshold value for the child queries. This value is required and must have the same number of elements as there are querylets for this combiner. This value is used to normalize the scores of the querylets. The intent is to allow each querylet to use the same cutoff point for scores considered a match verses those considered a non-match.

The score for each querylet is normalized so that a score equal to its match cutoff score defined here is set equal to the match cutoff score of the first querylet. Scores greater or less than the match cutoff score are adjusted using linear interpolation. Note this means the score of the first querylet is not changed. A negative score means the absolute cutoff score for the query should be used as the match cutoff score. If no absolute cut off score is defined for this query a negative score is rejected with a DVK_ERR_PARAMVAL error. Match cutoff scores above 1.0 are rejected with a DVK_ERR_PARAMVAL error.

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LPAR_BOOL_INVALID_ONLY indicates whether querylets with confidence values greater than or less than the confidence cutoff score are kept. This value is optional. The default value is false. If this value is true, the first querylet with a confidence value less than or equal to the confidence cutoff score is used. If false or not given, the first querylet with a confidence value greater than or equal to the cutoff score is used.

This combiner scans its querylets in the order given. The first querylet that meets its confidence cutoff test is used to supply the scores and the confidence value returned by this combiner. If no querylet meets its confidence cutoff test the special -1.0 score is returned to reject this record.