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Query Model Evaluation Application

This application (QueryModelEval.cpp) loads an expanded query model (e.g., one computed by GenerateQueryModel), and evaluates it with the KL-divergence retrieval model.

Parameters:

1. index: The complete name of the index table-of-content file for the database index.

2. smoothSupportFile: The name of the smoothing support file (e.g., one generated by GenerateSmoothSupport).

3. queryModel: the file of the query model to be evaluted

4. resultFile: the result file

5. resultFormat: whether the result format should be of the TREC format (i.e., six-column) or just a simple three-column format <queryID, docID, score>. Integer value, zero for non-TREC format, and non-zero for TREC format. Default: 1 (i.e., TREC format)

6. resultCount: the number of documents to return as result for each query

   The following are document model smoothing parameters:

7. smoothMethod: One of the three: Jelinek-Mercer (0), Dirichlet prior (1), and Absolute discounting (2)

8. smoothStrategy: Either interpolate (0) or backoff (1)

9. adjustedScoreMethod: Which type of score to output, one of:
   • "querylikelihood" or "ql" for query likelihood.
   • "crossentropy" or "ce" for cross entropy.
   • "negativekld" or "-d" for negative KL divergence.
10. JelinekMercerLambda: The collection model weight in the JM interpolation method. Default: 0.5

11. DirichletPrior: The prior parameter in the Dirichlet prior smoothing method. Default: 1000

12. discountDelta: The delta (discounting constant) in the absolute discounting method. Default 0.7.

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