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From andy <yhl...@sohu.com>
Subject RE: Length of the filed does not affect the doc score accurately for chinese analyzer(SmartChineseAnalyzer)
Date Wed, 12 Feb 2014 09:53:18 GMT
Thanks Uwe,could you please give me a more detail example about how to change
the lucene behavior


Uwe Schindler wrote
> Hi Erick,
> 
> a statement like " Adding &debug=all to the query will show you if this is
> the case" will not help a Lucene user, as it is only available in the Solr
> server. But Andy uses Lucene directly. In his case he should use
> IndexSearcher's explain functionalities to retrieve a structured output of
> how the documents are scored for this query for debugging:
> 
> http://lucene.apache.org/core/4_6_0/core/org/apache/lucene/search/IndexSearcher.html#explain(org.apache.lucene.search.Query,
> int)
> 
> But yes, the length norm is encoded with loss of precsision in Lucene (it
> is a float values encoded to 1 byte only). With Lucene 4 there are ways to
> change that behavior, but that included changing the similarity
> implementation and use a different DocValues type for encoding the norms.
> In most cases this is not needed, because user won't notice.
> 
> Uwe
> 
> -----
> Uwe Schindler
> H.-H.-Meier-Allee 63, D-28213 Bremen
> http://www.thetaphi.de
> eMail: 

> uwe@

> 
> 
>> -----Original Message-----
>> From: Erick Erickson [mailto:

> erickerickson@

> ]
>> Sent: Wednesday, January 15, 2014 1:30 PM
>> To: java-user
>> Subject: Re: Length of the filed does not affect the doc score accurately
>> for
>> chinese analyzer(SmartChineseAnalyzer)
>> 
>> the lengths of fields are encoded and lose some precision. So I suspect
>> the
>> length of the field calculated for the two documents are the same after
>> encoding.
>> 
>> Adding &debug=all to the query will show you if this is the case.
>> 
>> Best
>> Erick
>> 
>> On Wed, Jan 15, 2014 at 3:39 AM, andy &lt;

> yhlweb@

> &gt; wrote:
>> > Hi guys,
>> >
>> > As the topic,it seems that the length of filed does not affect the doc
>> > score accurately for chinese analyzer in my source code
>> >
>> > index source code
>> >
>> >  private static Directory DIRECTORY;
>> >
>> >
>> >     @BeforeClass
>> >     public static void before() throws IOException {
>> >           DIRECTORY = new RAMDirectory();
>> >           Analyzer chineseanalyzer = new
>> > SmartChineseAnalyzer(Version.LUCENE_40);
>> >           IndexWriterConfig indexWriterConfig = new
>> > IndexWriterConfig(Version.LUCENE_40,chineseanalyzer);
>> >           FieldType nameType = new FieldType();
>> >           nameType.setIndexed(true);
>> >           nameType.setStored(true);
>> >           nameType.setOmitNorms(false);
>> >           try {
>> >               IndexWriter indexWriter = new IndexWriter(DIRECTORY,
>> > indexWriterConfig);
>> >
>> >               List
> <String>
>  nameList = new ArrayList
> <String>
> ();
>> >
>> > nameList.add("咨询公司");nameList.add("飞鹰咨询管理咨询公司
>> ");nameList.add("北京中标咨询公司");nameList.add("重庆咨询公司
>> ");nameList.add("商务咨询服务公司");nameList.add("法律咨询公司");
>> >               for (int i = 0; i < nameList.size(); i++) {
>> >                   Document document = new Document();
>> >                   document.add(new Field("name", nameList.get(i),
>> > nameType));
>> >                   document.add(new
>> > Field("id",String.valueOf(i+1),nameType));
>> >                   indexWriter.addDocument(document);
>> >             }
>> >               indexWriter.commit();
>> >           } catch (IOException e) {
>> >               // TODO Auto-generated catch block
>> >               e.printStackTrace();
>> >           }
>> >     }
>> >
>> > search snippet:
>> >  @Test
>> >     public void testChinese() throws IOException, ParseException {
>> >         String keyword = "咨询公司";
>> >         System.out.println("Searching for:" + keyword);
>> >         System.out.println();
>> >         IndexReader indexReader = DirectoryReader.open(DIRECTORY);
>> >         IndexSearcher indexSearcher = new IndexSearcher(indexReader);
>> >         Query query = null;
>> >         query = new QueryParser(Version.LUCENE_40,"name",new
>> > SmartChineseAnalyzer(Version.LUCENE_40)).parse(keyword);
>> >         TopDocs topDocs = indexSearcher.search(query,15);
>> >         System.out.println("Search Result:");
>> >         if (null !=topDocs && 0 < topDocs.totalHits) {
>> >             for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
>> >                 System.out.println("doc id:" +
>> > indexSearcher.doc(scoreDoc.doc).get("id"));
>> >                 String name =
>> indexSearcher.doc(scoreDoc.doc).get("name");
>> >                 System.out.println("content of Field:" + name);
>> >                 dumpCNTokens(name);
>> >                 System.out.println("score:" + scoreDoc.score);
>> >
>> > System.out.println("-------------------------------------------");
>> >             }
>> >         } else {
>> >             System.out.println("no results");
>> >         }
>> >
>> >     }
>> >
>> >
>> > And search result as follows:
>> > Searching for:咨询公司
>> >
>> > Search Result:
>> > doc id:1
>> > content of Field:咨询公司
>> > Terms:咨询        公司
>> > score:0.74763227
>> > -------------------------------------------
>> > doc id:2
>> > content of Field:飞鹰咨询管理咨询公司
>> > Terms:飞鹰        咨询      管理      咨询      公司
>> > score:0.6317303
>> > -------------------------------------------
>> > doc id:3
>> > content of Field:北京中标咨询公司
>> > Terms:北京        中标      咨询      公司
>> > score:0.5981058
>> > -------------------------------------------
>> > doc id:4
>> > content of Field:重庆咨询公司
>> > Terms:重庆        咨询      公司
>> > score:0.5981058
>> > -------------------------------------------
>> > doc id:5
>> > content of Field:商务咨询服务公司
>> > Terms:商务        咨询      服务      公司
>> > score:0.5981058
>> > -------------------------------------------
>> > doc id:6
>> > content of Field:法律咨询公司
>> > Terms:法律        咨询      公司
>> > score:0.5981058
>> > -------------------------------------------
>> >
>> > docs:3,4,5,6 have the same score, but I think the doc 4 and doc 6
>> > should have a higner score than the doc 3,5, becase the doc 4 and doc
>> > 6 have three terms ,doc 3,5 have four terms.
>> > Am I right? who can give me a explanation? And how to get the expected
>> > result?
>> >
>> >
>> >
>> > --
>> > View this message in context:
>> > http://lucene.472066.n3.nabble.com/Length-of-the-filed-does-not-affect
>> > -the-doc-score-accurately-for-chinese-analyzer-SmartChineseAnalyz-tp41
>> > 11390.html Sent from the Lucene - Java Users mailing list archive at
>> > Nabble.com.
>> >
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