Document precision requirements of setBoost calls -------------------------------------------------
Key: LUCENE-3957 URL: https://issues.apache.org/jira/browse/LUCENE-3957 Project: Lucene - Java Issue Type: Improvement Components: general/javadocs Affects Versions: 3.5 Reporter: Jordi Salvat i Alabart The behaviour of index-time boosts seems pretty erratic (e.g. a boost of 8.0 produces the exact same score as a boost of 9.0) until you become aware that these factors end up encoded in a single byte, with a three-bit mantissa. This consumed a whole day of research for us, and I still believe we were lucky to spot it, given how deeply dug into the code & documentation this information is. I suggest adding a small note to the JavaDoc of setBoost methods in Document, Fieldable, FieldInvertState, and possibly AbstractField, Field, and NumericField. Suggested text: "Note that all index-time boost values end up encoded using Similarity.encodeNormValue, with a 3-bit mantissa -- so differences in the boost value of less than 25% may easily be rounded away." -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org