%iFind.Rank.TFIDF

hidden class %iFind.Rank.TFIDF extends %iFind.Rank.Abstract

This class provides the default ranking algorithm, using a TF component based on term frequency ([frequency] / [word count]) and a smoothed Inverse Document Frequency component ( log(1 + ([total doc count] / [document frequency])) ).

When there are multiple matching words for a search leaf node, the "best" one's score will be used for that node. Wen the search leaf node refers to a multi-word string (positional / entity), the score will be multiplied with the log of the word count + 1 to express the fact that this is a more strict search criterion.

Property Inventory

• GlobalWordWeights
• LeafWords
• RecordWordCount
• RecordWordWeights
• TotalRecordCount

Properties

property GlobalWordWeights [ MultiDimensional ];

GlobalWordWeights([wordid]) = [IDF score] Populated as part of OnInitialize().

Property methods: GlobalWordWeightsDisplayToLogical(), GlobalWordWeightsGet(), GlobalWordWeightsIsValid(), GlobalWordWeightsLogicalToDisplay(), GlobalWordWeightsLogicalToOdbc(), GlobalWordWeightsNormalize(), GlobalWordWeightsSet()

property LeafWords [ MultiDimensional ];

LeafWords([node],[leaf],[position],[WordId]) = "" Populated as part of OnInitialize().

Property methods: LeafWordsDisplayToLogical(), LeafWordsGet(), LeafWordsIsValid(), LeafWordsLogicalToDisplay(), LeafWordsLogicalToOdbc(), LeafWordsNormalize(), LeafWordsSet()

property RecordWordCount as %Integer;

The total number of words in the current document. Populated/updated as part of OnBeforeGetRecordScore().

Property methods: RecordWordCountDisplayToLogical(), RecordWordCountGet(), RecordWordCountIsValid(), RecordWordCountLogicalToDisplay(), RecordWordCountNormalize(), RecordWordCountSet()

property RecordWordWeights [ MultiDimensional ];

RecordWordWeights([wordid]) = [freq in record]/[..RecordWordCount] Populated/updated as part of OnBeforeGetRecordScore().

Property methods: RecordWordWeightsDisplayToLogical(), RecordWordWeightsGet(), RecordWordWeightsIsValid(), RecordWordWeightsLogicalToDisplay(), RecordWordWeightsLogicalToOdbc(), RecordWordWeightsNormalize(), RecordWordWeightsSet()

property TotalRecordCount as %Integer;

The total record count for the index being searched. Populated as part of OnInitialize().

Property methods: TotalRecordCountDisplayToLogical(), TotalRecordCountGet(), TotalRecordCountIsValid(), TotalRecordCountLogicalToDisplay(), TotalRecordCountNormalize(), TotalRecordCountSet()