范德萨发而为
全部博文(392)
发布时间:2013-06-18 16:22:53
结合下面两篇文章的描述:Lucene只用一个字节来表示一个float数据,所以这个数据相对于使用32bit来表示float,精度损失更大,这个是保存norm数据时需要严重考虑的问题Norms (.f[0-9]*) –> SegSize 在Lucene 2.1.........【阅读全文】
发布时间:2013-06-18 15:50:28
Apache Lucene turned 10 last year with a limitation that bugged many many users from day one. You may know Lucene’s core scoring model is based on TF/IDF (Vector Space Model). Lucene encapsulates all related calculations in a class called Similarity. Among pure TF/IDF factors Simil.........【阅读全文】
发布时间:2013-06-18 12:44:16
Lucene's default similarity functionLucene's scoring Function is defined by the function where tf(t in d) denotes the term's frequency, defined as the number of times the term t appears in the currently scored document d. Documents that have more occ.........【阅读全文】
发布时间:2013-06-17 22:48:30
1. 同步概念Xapian没有显示的支持多线程,为了避免不必要的线程死锁,Xapian没有使用任何全局变量,所以你可以你的多线程应用中放心的使用Xapain对象,但是一些Xapian对象内部是有关联的,如Xapian::Database::get_document(),返回的对象Xapian::Document对象内部保存了一个指向DataBase的一个引用,所以它不适合在多.........【阅读全文】
发布时间:2013-06-15 11:01:19
used index statistics per index segment, and make them available at search time. To understand the new statistics, let's pretend we've indexed the following two example documents, each with only one field "title":document 1: The Lion, the Witch, and the Wardrobedocument 2: The Da.........【阅读全文】
CU博客助理2013-01-08 14:27
chinaunix网友2010-04-18 14:30
你好,可以麻烦你加我的qq么:852476785 看了你hadoop那篇编程,Sogo日志分析那个,想请教一下。。。。非常非常非常非常非常非常感性吖