[LUCENE-6982] throw IAE on illegal bm25 parameter values

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 5.5, 6.0
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Robert Muir
• Created: 18/Jan/16 12:15
• Updated: 28/Aug/22 14:48
• Resolved: 18/Jan/16 21:32

Description

Rather than strange behavior, we should throw an exception if these values are wrong.

This can often detect if the two values got "mixed up", because typical values of k1 are > 1 (e.g. 1.2, 2.0), but b is only defined between 0 and 1.