IndexOrderSearcher: sort data before indexing and use
1/docID instead of score as sort field
--------------------------------------------------------------------------------
From: Che Dong
Subject: IndexOrderSearcher: sort data before indexing
and use 1/docID instead of score as sort field
Date: Tue, 05 Mar 2002 01:52:29 -0800
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Hi all:
I think many lucene user want sort lucene results on
some certain field. but
just like Doug said: The problem is that a call to
getField() makes searches
an order of magnitude slower.
for example: many lucene apps base on database, just
sort data by date, rank
... even some complex: rank * price....
and dump into lucene index with sorted order.
when searching, with same lucene index, you can choose
return search results
with two sort method:
use IndexSearcher: return results with default sort
method by score
use IndexOrderSearcher: return results with doc added
sequence.
I tested with (float) doc and (float) 1/doc and find
1/doc more similar to
range of score.
Che Dong
beside class name, the only difference between
IndexOrderSearcher.java and
IndexSearch.java is IndexOrderSearcher use
(float) 1/docID as score field while just use score
filter results with
minScore in search() method.
diff IndexOrderSearcher.java IndexSearch.java
66,67c66,67
< /** Implements search over a single IndexReader. and
sort by document id*/
< public final class IndexOrderSearcher extends
Searcher {
---
> /** Implements search over a single IndexReader. */
> public final class IndexSearcher extends Searcher {
71c71
< public IndexOrderSearcher(String path) throws
IOException {
---
> public IndexSearcher(String path) throws
IOException {
76c76
< public IndexOrderSearcher(Directory directory)
throws IOException {
---
> public IndexSearcher(Directory directory) throws
IOException {
81c81
< public IndexOrderSearcher(IndexReader r) {
---
> public IndexSearcher(IndexReader r) {
119,120c119
< //use 1/doc instead of score as sort
field
< hq.put(new ScoreDoc(doc, (float)
1/doc)); // update
hit queue
---
> hq.put(new ScoreDoc(doc, score)); //
update hit queue
159,160c158
< //use 1/doc instead of score as sort
field
< results.collect(doc, (float) 1/doc);
---
> results.collect(doc, score);
--- Clemens Marschner <cmad@lanlab.de> µÄÕýÎÄ£º> Hi,
>
> I'd like to have an extra field added to each
> document where I can put some
> custom "document ranks" in, i.e. PageRank or some
> preference how current the
> document is, so that more current documents are
> preferred (i.e. in a course
> list). Any ideas?
>
> Clemens
>
>
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