Thanks for your answer. I checked what explain() says about my queries, and:
MatchAllDocsQuery:
1.0 = (MATCH) MatchAllDocsQuery, product of:
1.0 = queryNorm
FieldScoreQuery:
0.5 = (MATCH) float(ratio), product of:
0.5 = float(ratio)=0.5
1.0 = boost
1.0 = queryNorm
CustomScoreQuery:
0.24999999 = (MATCH) custom(*:*, float(ratio)), product of:
0.24999999 = custom score: product of:
0.70710677 = (MATCH) MatchAllDocsQuery, product of:
0.70710677 = queryNorm
0.35355338 = (MATCH) float(ratio), product of:
0.5 = float(ratio)=0.5
1.0 = boost
0.70710677 = queryNorm
1.0 = queryBoost
so the reason is queryNorm.
I've done this test, because I wanted to write my own CustomScoreQuery
and I was trying to understand what's happening in customScore(int doc,
float subQueryScore, float valSrcScore) method of CustomScoreProvider. I
assumed, that if I use FieldScoreQuery as valueSourceQuery, valSrcScore
parameter will be equal to field value, but it's not true. So now I'm
using FieldCache to obtain field value from index and use it in my own
score function (there is one value per document in this field in my
index). It looks something like this:
public float customScore(int doc, float subQueryScore, float valSrcScore)
throws IOException {
float fieldValue = FieldCache.DEFAULT.getFloats(reader, "ratio")[doc];
float newValSrcScore = someFunction(someQueryTimeVariable, fieldValue);
return super.customScore(doc, subQueryScore, newValSrcScore);
}
Am I right, or is there a better way to get field value?
--
Dominika
On 20.02.2012 18:38, Ian Lea wrote:
I can't explain this. Can you get at an oal.search.Explanation? You
could write your own CustomScoreProvider - that might help you to
double check what is being passed to it, and/or allow you to provide
your own calculation.
--
Ian.
On Thu, Feb 16, 2012 at 8:32 PM, Dominika Puzio
<dominika.pu...@gmail.com> wrote:
Hello,
I'm trying to understand the behavior of CustomScoreQuery. It seemed to me,
that default
CustomScoreQuery(Query subQuery, ValueSourceQuery valSrcQuery)
should return a score that is a product of subQuery score
and valSrcQuery score. So I wrote a simple test case given below:
@Test
public void createAndQueryIndex() throws CorruptIndexException,
LockObtainFailedException, IOException {
RAMDirectory dir = new RAMDirectory();
IndexWriter writer = new IndexWriter(dir,
new IndexWriterConfig(Version.LUCENE_35,
new StandardAnalyzer(
Version.LUCENE_35)));
Document doc = new Document();
doc.add(new Field("name", "name", Store.YES, Index.NOT_ANALYZED));
doc.add(new Field("ratio", "0.5", Store.YES, Index.NOT_ANALYZED));
writer.addDocument(doc);
writer.close();
IndexSearcher searcher = new IndexSearcher(IndexReader.open(dir));
Query matchAllDocs = new MatchAllDocsQuery();
float score1 = searcher.search(matchAllDocs,
1).scoreDocs[0].score;
Assert.assertEquals(1.0f, score1, 0);
ValueSourceQuery fieldScoreQuery = new FieldScoreQuery("ratio",
FieldScoreQuery.Type.FLOAT);
float score2 = searcher.search(fieldScoreQuery,
1).scoreDocs[0].score;
Assert.assertEquals(0.5f, score2, 0);
CustomScoreQuery csq = new CustomScoreQuery(matchAllDocs,
fieldScoreQuery);
float score3 = searcher.search(csq, 1).scoreDocs[0].score;
Assert.assertEquals(score1*score2, score3, 0);
searcher.close();
}
But this test fails in third assertion - score3 is 0.249. Can someone
explain why? How the score3 is computed in this case?
--
Regards
Dominika Puzio
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